test/Transforms/InstCombine/conditional-variable-length-signext-after-high-bit-extract.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s

; If we extract (via lshr) some high bits, and then perform their sign-extension
; conditionally depending on whether the extracted value is negative or not
; (i.e. interpreting the highest extracted bit, which was the original signbit
; of the value from which we extracted as a signbit), then we should just
; perform extraction via `ashr`.

; Base patterns.

declare void @use1(i1)
declare void @use16(i16)
declare void @use32(i32)
declare void @use64(i64)

define i32 @t0_notrunc_add(i32 %data, i32 %nbits) {
; CHECK-LABEL: @t0_notrunc_add(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @t0_notrunc_or(i32 %data, i32 %nbits) {
; CHECK-LABEL: @t0_notrunc_or(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = or i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @t1_notrunc_sub(i32 %data, i32 %nbits) {
; CHECK-LABEL: @t1_notrunc_sub(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[HIGHER_BIT_AFTER_SIGNBIT:%.*]] = shl nuw i32 1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[HIGHER_BIT_AFTER_SIGNBIT]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[HIGHER_BIT_AFTER_SIGNBIT]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %higher_bit_after_signbit = shl i32 1, %nbits
  %magic = select i1 %should_signext, i32 %higher_bit_after_signbit, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %higher_bit_after_signbit)
  call void @use32(i32 %magic)

  %signextended = sub i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @t2_trunc_add(i64 %data, i32 %nbits) {
; CHECK-LABEL: @t2_trunc_add(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]]
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[LOW_BITS_TO_SKIP]] to i64
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED_WIDE:%.*]] = lshr i64 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED_WIDE]] to i32
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i64 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use64(i64 [[LOW_BITS_TO_SKIP_WIDE]])
; CHECK-NEXT:    call void @use64(i64 [[HIGH_BITS_EXTRACTED_WIDE]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    [[TMP1:%.*]] = ashr i64 [[DATA]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = trunc i64 [[TMP1]] to i32
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 64, %nbits
  %low_bits_to_skip_wide = zext i32 %low_bits_to_skip to i64
  %high_bits_extracted_wide = lshr i64 %data, %low_bits_to_skip_wide
  %high_bits_extracted = trunc i64 %high_bits_extracted_wide to i32
  %should_signext = icmp slt i64 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0 ; one-use

  call void @use32(i32 %low_bits_to_skip)
  call void @use64(i64 %low_bits_to_skip_wide)
  call void @use64(i64 %high_bits_extracted_wide)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)

  %signextended = add i32 %magic, %high_bits_extracted
  ret i32 %signextended
}

define i32 @t2_trunc_or(i64 %data, i32 %nbits) {
; CHECK-LABEL: @t2_trunc_or(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]]
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[LOW_BITS_TO_SKIP]] to i64
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED_WIDE:%.*]] = lshr i64 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED_WIDE]] to i32
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i64 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use64(i64 [[LOW_BITS_TO_SKIP_WIDE]])
; CHECK-NEXT:    call void @use64(i64 [[HIGH_BITS_EXTRACTED_WIDE]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    [[TMP1:%.*]] = ashr i64 [[DATA]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = trunc i64 [[TMP1]] to i32
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 64, %nbits
  %low_bits_to_skip_wide = zext i32 %low_bits_to_skip to i64
  %high_bits_extracted_wide = lshr i64 %data, %low_bits_to_skip_wide
  %high_bits_extracted = trunc i64 %high_bits_extracted_wide to i32
  %should_signext = icmp slt i64 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0 ; one-use

  call void @use32(i32 %low_bits_to_skip)
  call void @use64(i64 %low_bits_to_skip_wide)
  call void @use64(i64 %high_bits_extracted_wide)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)

  %signextended = or i32 %magic, %high_bits_extracted
  ret i32 %signextended
}

define i32 @t3_trunc_sub(i64 %data, i32 %nbits) {
; CHECK-LABEL: @t3_trunc_sub(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]]
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[LOW_BITS_TO_SKIP]] to i64
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED_WIDE:%.*]] = lshr i64 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED_WIDE]] to i32
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i64 [[DATA]], 0
; CHECK-NEXT:    [[HIGHER_BIT_AFTER_SIGNBIT:%.*]] = shl nuw i32 1, [[NBITS]]
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use64(i64 [[LOW_BITS_TO_SKIP_WIDE]])
; CHECK-NEXT:    call void @use64(i64 [[HIGH_BITS_EXTRACTED_WIDE]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[HIGHER_BIT_AFTER_SIGNBIT]])
; CHECK-NEXT:    [[TMP1:%.*]] = ashr i64 [[DATA]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = trunc i64 [[TMP1]] to i32
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 64, %nbits
  %low_bits_to_skip_wide = zext i32 %low_bits_to_skip to i64
  %high_bits_extracted_wide = lshr i64 %data, %low_bits_to_skip_wide
  %high_bits_extracted = trunc i64 %high_bits_extracted_wide to i32
  %should_signext = icmp slt i64 %data, 0
  %higher_bit_after_signbit = shl i32 1, %nbits
  %magic = select i1 %should_signext, i32 %higher_bit_after_signbit, i32 0 ; one-use

  call void @use32(i32 %low_bits_to_skip)
  call void @use64(i64 %low_bits_to_skip_wide)
  call void @use64(i64 %high_bits_extracted_wide)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %higher_bit_after_signbit)

  %signextended = sub i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

; Commutativity

define i32 @t4_commutativity0(i32 %data, i32 %nbits) {
; CHECK-LABEL: @t4_commutativity0(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}
define i32 @t5_commutativity1(i32 %data, i32 %nbits) {
; CHECK-LABEL: @t5_commutativity1(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp sgt i32 [[DATA]], -1
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 0, i32 [[ALL_BITS_EXCEPT_LOW_NBITS]]
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp sgt i32 %data, -1 ; swapped
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 0, i32 %all_bits_except_low_nbits ; swapped

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}
define i32 @t6_commutativity2(i32 %data, i32 %nbits) {
; CHECK-LABEL: @t6_commutativity2(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %magic, %high_bits_extracted ; swapped
  ret i32 %signextended
}

; Extra uses

define i32 @t7_trunc_extrause0(i64 %data, i32 %nbits) {
; CHECK-LABEL: @t7_trunc_extrause0(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]]
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[LOW_BITS_TO_SKIP]] to i64
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED_WIDE:%.*]] = lshr i64 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED_WIDE]] to i32
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i64 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use64(i64 [[LOW_BITS_TO_SKIP_WIDE]])
; CHECK-NEXT:    call void @use64(i64 [[HIGH_BITS_EXTRACTED_WIDE]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    [[TMP1:%.*]] = ashr i64 [[DATA]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = trunc i64 [[TMP1]] to i32
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 64, %nbits
  %low_bits_to_skip_wide = zext i32 %low_bits_to_skip to i64
  %high_bits_extracted_wide = lshr i64 %data, %low_bits_to_skip_wide
  %high_bits_extracted = trunc i64 %high_bits_extracted_wide to i32 ; has extra use
  %should_signext = icmp slt i64 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0 ; one-use

  call void @use32(i32 %low_bits_to_skip)
  call void @use64(i64 %low_bits_to_skip_wide)
  call void @use64(i64 %high_bits_extracted_wide)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)

  %signextended = add i32 %magic, %high_bits_extracted
  ret i32 %signextended
}
define i32 @t8_trunc_extrause1(i64 %data, i32 %nbits) {
; CHECK-LABEL: @t8_trunc_extrause1(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]]
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[LOW_BITS_TO_SKIP]] to i64
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED_WIDE:%.*]] = lshr i64 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i64 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use64(i64 [[LOW_BITS_TO_SKIP_WIDE]])
; CHECK-NEXT:    call void @use64(i64 [[HIGH_BITS_EXTRACTED_WIDE]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[TMP1:%.*]] = ashr i64 [[DATA]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = trunc i64 [[TMP1]] to i32
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 64, %nbits
  %low_bits_to_skip_wide = zext i32 %low_bits_to_skip to i64
  %high_bits_extracted_wide = lshr i64 %data, %low_bits_to_skip_wide
  %high_bits_extracted = trunc i64 %high_bits_extracted_wide to i32 ; one-use
  %should_signext = icmp slt i64 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0 ; has extra use

  call void @use32(i32 %low_bits_to_skip)
  call void @use64(i64 %low_bits_to_skip_wide)
  call void @use64(i64 %high_bits_extracted_wide)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %magic, %high_bits_extracted
  ret i32 %signextended
}
define i32 @n9_trunc_extrause2(i64 %data, i32 %nbits) {
; CHECK-LABEL: @n9_trunc_extrause2(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]]
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[LOW_BITS_TO_SKIP]] to i64
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED_WIDE:%.*]] = lshr i64 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED_WIDE]] to i32
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i64 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use64(i64 [[LOW_BITS_TO_SKIP_WIDE]])
; CHECK-NEXT:    call void @use64(i64 [[HIGH_BITS_EXTRACTED_WIDE]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[MAGIC]], [[HIGH_BITS_EXTRACTED]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 64, %nbits
  %low_bits_to_skip_wide = zext i32 %low_bits_to_skip to i64
  %high_bits_extracted_wide = lshr i64 %data, %low_bits_to_skip_wide
  %high_bits_extracted = trunc i64 %high_bits_extracted_wide to i32 ; has extra use
  %should_signext = icmp slt i64 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0 ; has extra use

  call void @use32(i32 %low_bits_to_skip)
  call void @use64(i64 %low_bits_to_skip_wide)
  call void @use64(i64 %high_bits_extracted_wide)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %magic, %high_bits_extracted
  ret i32 %signextended
}

define i32 @t10_preserve_exact(i32 %data, i32 %nbits) {
; CHECK-LABEL: @t10_preserve_exact(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr exact i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr exact i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr exact i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @t11_different_zext_of_shamt(i32 %data, i8 %nbits) {
; CHECK-LABEL: @t11_different_zext_of_shamt(
; CHECK-NEXT:    [[NBITS_16BIT:%.*]] = zext i8 [[NBITS:%.*]] to i16
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub nsw i16 32, [[NBITS_16BIT]]
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP_32:%.*]] = zext i16 [[LOW_BITS_TO_SKIP]] to i32
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_32]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[NBITS_32BIT:%.*]] = zext i8 [[NBITS]] to i32
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS_32BIT]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use16(i16 [[NBITS_16BIT]])
; CHECK-NEXT:    call void @use16(i16 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP_32]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[NBITS_32BIT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP_32]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %nbits_16bit = zext i8 %nbits to i16
  %low_bits_to_skip = sub i16 32, %nbits_16bit
  %low_bits_to_skip_32 = zext i16 %low_bits_to_skip to i32
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip_32
  %should_signext = icmp slt i32 %data, 0
  %nbits_32bit = zext i8 %nbits to i32
  %all_bits_except_low_nbits = shl i32 -1, %nbits_32bit
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use16(i16 %nbits_16bit)
  call void @use16(i16 %low_bits_to_skip)
  call void @use32(i32 %low_bits_to_skip_32)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %nbits_32bit)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @t12_add_sext_of_magic(i32 %data, i8 %nbits) {
; CHECK-LABEL: @t12_add_sext_of_magic(
; CHECK-NEXT:    [[NBITS_32BIT:%.*]] = zext i8 [[NBITS:%.*]] to i32
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub nsw i32 32, [[NBITS_32BIT]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[NBITS_16BIT:%.*]] = zext i8 [[NBITS]] to i16
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i16 -1, [[NBITS_16BIT]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i16 [[ALL_BITS_EXCEPT_LOW_NBITS]], i16 0
; CHECK-NEXT:    [[MAGIC_WIDE:%.*]] = sext i16 [[MAGIC]] to i32
; CHECK-NEXT:    call void @use32(i32 [[NBITS_32BIT]])
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use16(i16 [[NBITS_16BIT]])
; CHECK-NEXT:    call void @use16(i16 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use16(i16 [[MAGIC]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC_WIDE]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %nbits_32bit = zext i8 %nbits to i32
  %low_bits_to_skip = sub i32 32, %nbits_32bit
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %nbits_16bit = zext i8 %nbits to i16
  %all_bits_except_low_nbits = shl i16 -1, %nbits_16bit
  %magic = select i1 %should_signext, i16 %all_bits_except_low_nbits, i16 0
  %magic_wide = sext i16 %magic to i32

  call void @use32(i32 %nbits_32bit)
  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use16(i16 %nbits_16bit)
  call void @use16(i16 %all_bits_except_low_nbits)
  call void @use16(i16 %magic)
  call void @use32(i32 %magic_wide)

  %signextended = add i32 %high_bits_extracted, %magic_wide
  ret i32 %signextended
}

define i32 @t13_sub_zext_of_magic(i32 %data, i8 %nbits) {
; CHECK-LABEL: @t13_sub_zext_of_magic(
; CHECK-NEXT:    [[NBITS_32BIT:%.*]] = zext i8 [[NBITS:%.*]] to i32
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub nsw i32 32, [[NBITS_32BIT]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[NBITS_16BIT:%.*]] = zext i8 [[NBITS]] to i16
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl nuw i16 1, [[NBITS_16BIT]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i16 [[ALL_BITS_EXCEPT_LOW_NBITS]], i16 0
; CHECK-NEXT:    [[MAGIC_WIDE:%.*]] = zext i16 [[MAGIC]] to i32
; CHECK-NEXT:    call void @use32(i32 [[NBITS_32BIT]])
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use16(i16 [[NBITS_16BIT]])
; CHECK-NEXT:    call void @use16(i16 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use16(i16 [[MAGIC]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC_WIDE]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %nbits_32bit = zext i8 %nbits to i32
  %low_bits_to_skip = sub i32 32, %nbits_32bit
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %nbits_16bit = zext i8 %nbits to i16
  %all_bits_except_low_nbits = shl i16 1, %nbits_16bit
  %magic = select i1 %should_signext, i16 %all_bits_except_low_nbits, i16 0
  %magic_wide = zext i16 %magic to i32

  call void @use32(i32 %nbits_32bit)
  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use16(i16 %nbits_16bit)
  call void @use16(i16 %all_bits_except_low_nbits)
  call void @use16(i16 %magic)
  call void @use32(i32 %magic_wide)

  %signextended = sub i32 %high_bits_extracted, %magic_wide
  ret i32 %signextended
}

define i32 @t14_add_sext_of_shl(i32 %data, i8 %nbits) {
; CHECK-LABEL: @t14_add_sext_of_shl(
; CHECK-NEXT:    [[NBITS_32BIT:%.*]] = zext i8 [[NBITS:%.*]] to i32
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub nsw i32 32, [[NBITS_32BIT]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[NBITS_16BIT:%.*]] = zext i8 [[NBITS]] to i16
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i16 -1, [[NBITS_16BIT]]
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS_WIDE:%.*]] = sext i16 [[ALL_BITS_EXCEPT_LOW_NBITS]] to i32
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS_WIDE]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[NBITS_32BIT]])
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use16(i16 [[NBITS_16BIT]])
; CHECK-NEXT:    call void @use16(i16 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS_WIDE]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %nbits_32bit = zext i8 %nbits to i32
  %low_bits_to_skip = sub i32 32, %nbits_32bit
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %nbits_16bit = zext i8 %nbits to i16
  %all_bits_except_low_nbits = shl i16 -1, %nbits_16bit
  %all_bits_except_low_nbits_wide = sext i16 %all_bits_except_low_nbits to i32
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits_wide, i32 0

  call void @use32(i32 %nbits_32bit)
  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use16(i16 %nbits_16bit)
  call void @use16(i16 %all_bits_except_low_nbits)
  call void @use32(i32 %all_bits_except_low_nbits_wide)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @t15_sub_zext_of_shl(i32 %data, i8 %nbits) {
; CHECK-LABEL: @t15_sub_zext_of_shl(
; CHECK-NEXT:    [[NBITS_32BIT:%.*]] = zext i8 [[NBITS:%.*]] to i32
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub nsw i32 32, [[NBITS_32BIT]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[NBITS_16BIT:%.*]] = zext i8 [[NBITS]] to i16
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl nuw i16 1, [[NBITS_16BIT]]
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS_WIDE:%.*]] = zext i16 [[ALL_BITS_EXCEPT_LOW_NBITS]] to i32
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS_WIDE]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[NBITS_32BIT]])
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use16(i16 [[NBITS_16BIT]])
; CHECK-NEXT:    call void @use16(i16 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS_WIDE]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = ashr i32 [[DATA]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %nbits_32bit = zext i8 %nbits to i32
  %low_bits_to_skip = sub i32 32, %nbits_32bit
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %nbits_16bit = zext i8 %nbits to i16
  %all_bits_except_low_nbits = shl i16 1, %nbits_16bit
  %all_bits_except_low_nbits_wide = zext i16 %all_bits_except_low_nbits to i32
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits_wide, i32 0

  call void @use32(i32 %nbits_32bit)
  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use16(i16 %nbits_16bit)
  call void @use16(i16 %all_bits_except_low_nbits)
  call void @use32(i32 %all_bits_except_low_nbits_wide)
  call void @use32(i32 %magic)

  %signextended = sub i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

; Negative tests.

define i32 @n16(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n16(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 31, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 31, %nbits ; not 32
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n17_add(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n17_add(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl nuw i32 1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 1, %nbits ; not -1
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n18(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n18(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 0, i32 [[ALL_BITS_EXCEPT_LOW_NBITS]]
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 0, i32 %all_bits_except_low_nbits ; wrong order

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n19(i32 %data1, i32 %data2, i32 %nbits) {
; CHECK-LABEL: @n19(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA1:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA2:%.*]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data1, %low_bits_to_skip ; not %data2
  %should_signext = icmp slt i32 %data2, 0 ; not %data1
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n20(i32 %data, i32 %nbits1, i32 %nbits2) {
; CHECK-LABEL: @n20(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS1:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS2:%.*]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits1 ; not %nbits2
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits2 ; not %nbits1
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n21(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n21(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp sgt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp sgt i32 %data, 0 ; this isn't a sign bit test
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n22(i64 %data, i32 %nbits) {
; CHECK-LABEL: @n22(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 63, [[NBITS:%.*]]
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[LOW_BITS_TO_SKIP]] to i64
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED_WIDE:%.*]] = lshr i64 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_WIDE]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED_WIDE]] to i32
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i64 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use64(i64 [[LOW_BITS_TO_SKIP_WIDE]])
; CHECK-NEXT:    call void @use64(i64 [[HIGH_BITS_EXTRACTED_WIDE]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[MAGIC]], [[HIGH_BITS_EXTRACTED]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 63, %nbits ; not 64
  %low_bits_to_skip_wide = zext i32 %low_bits_to_skip to i64
  %high_bits_extracted_wide = lshr i64 %data, %low_bits_to_skip_wide
  %high_bits_extracted = trunc i64 %high_bits_extracted_wide to i32
  %should_signext = icmp slt i64 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use64(i64 %low_bits_to_skip_wide)
  call void @use64(i64 %high_bits_extracted_wide)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %magic, %high_bits_extracted
  ret i32 %signextended
}

define i32 @n23(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n23(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = ashr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = ashr i32 %data, %low_bits_to_skip ; not `lshr`
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n24(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n24(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[HIGHER_BIT_AFTER_SIGNBIT:%.*]] = shl nuw i32 1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[HIGHER_BIT_AFTER_SIGNBIT]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[HIGHER_BIT_AFTER_SIGNBIT]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = sub i32 [[MAGIC]], [[HIGH_BITS_EXTRACTED]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %higher_bit_after_signbit = shl i32 1, %nbits
  %magic = select i1 %should_signext, i32 %higher_bit_after_signbit, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %higher_bit_after_signbit)
  call void @use32(i32 %magic)

  %signextended = sub i32 %magic, %high_bits_extracted ; wrong order; `sub` is not commutative
  ret i32 %signextended
}

define i32 @n25_sub(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n25_sub(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[HIGHER_BIT_AFTER_SIGNBIT:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[HIGHER_BIT_AFTER_SIGNBIT]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[HIGHER_BIT_AFTER_SIGNBIT]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = sub i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %higher_bit_after_signbit = shl i32 -1, %nbits ; not 1
  %magic = select i1 %should_signext, i32 %higher_bit_after_signbit, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %higher_bit_after_signbit)
  call void @use32(i32 %magic)

  %signextended = sub i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n26(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n26(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 -1
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 -1, %nbits
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 -1 ; not 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = add i32 %high_bits_extracted, %magic
  ret i32 %signextended
}

define i32 @n27_add_zext_of_magic(i32 %data, i8 %nbits) {
; CHECK-LABEL: @n27_add_zext_of_magic(
; CHECK-NEXT:    [[NBITS_32BIT:%.*]] = zext i8 [[NBITS:%.*]] to i32
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub nsw i32 32, [[NBITS_32BIT]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[NBITS_16BIT:%.*]] = zext i8 [[NBITS]] to i16
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i16 -1, [[NBITS_16BIT]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i16 [[ALL_BITS_EXCEPT_LOW_NBITS]], i16 0
; CHECK-NEXT:    [[MAGIC_WIDE:%.*]] = zext i16 [[MAGIC]] to i32
; CHECK-NEXT:    call void @use32(i32 [[NBITS_32BIT]])
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use16(i16 [[NBITS_16BIT]])
; CHECK-NEXT:    call void @use16(i16 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use16(i16 [[MAGIC]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC_WIDE]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = add i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC_WIDE]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %nbits_32bit = zext i8 %nbits to i32
  %low_bits_to_skip = sub i32 32, %nbits_32bit
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %nbits_16bit = zext i8 %nbits to i16
  %all_bits_except_low_nbits = shl i16 -1, %nbits_16bit
  %magic = select i1 %should_signext, i16 %all_bits_except_low_nbits, i16 0
  %magic_wide = zext i16 %magic to i32 ; not sext

  call void @use32(i32 %nbits_32bit)
  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use16(i16 %nbits_16bit)
  call void @use16(i16 %all_bits_except_low_nbits)
  call void @use16(i16 %magic)
  call void @use32(i32 %magic_wide)

  %signextended = add i32 %high_bits_extracted, %magic_wide
  ret i32 %signextended
}

define i32 @n28_sub_sext_of_magic(i32 %data, i8 %nbits) {
; CHECK-LABEL: @n28_sub_sext_of_magic(
; CHECK-NEXT:    [[NBITS_32BIT:%.*]] = zext i8 [[NBITS:%.*]] to i32
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub nsw i32 32, [[NBITS_32BIT]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[NBITS_16BIT:%.*]] = zext i8 [[NBITS]] to i16
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl nuw i16 1, [[NBITS_16BIT]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i16 [[ALL_BITS_EXCEPT_LOW_NBITS]], i16 0
; CHECK-NEXT:    [[MAGIC_WIDE:%.*]] = sext i16 [[MAGIC]] to i32
; CHECK-NEXT:    call void @use32(i32 [[NBITS_32BIT]])
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use16(i16 [[NBITS_16BIT]])
; CHECK-NEXT:    call void @use16(i16 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use16(i16 [[MAGIC]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC_WIDE]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = sub i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC_WIDE]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %nbits_32bit = zext i8 %nbits to i32
  %low_bits_to_skip = sub i32 32, %nbits_32bit
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %nbits_16bit = zext i8 %nbits to i16
  %all_bits_except_low_nbits = shl i16 1, %nbits_16bit
  %magic = select i1 %should_signext, i16 %all_bits_except_low_nbits, i16 0
  %magic_wide = sext i16 %magic to i32 ; not zext

  call void @use32(i32 %nbits_32bit)
  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use16(i16 %nbits_16bit)
  call void @use16(i16 %all_bits_except_low_nbits)
  call void @use16(i16 %magic)
  call void @use32(i32 %magic_wide)

  %signextended = sub i32 %high_bits_extracted, %magic_wide
  ret i32 %signextended
}

define i32 @n290_or_with_wrong_magic(i32 %data, i32 %nbits) {
; CHECK-LABEL: @n290_or_with_wrong_magic(
; CHECK-NEXT:    [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]]
; CHECK-NEXT:    [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]]
; CHECK-NEXT:    [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0
; CHECK-NEXT:    [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl nuw i32 1, [[NBITS]]
; CHECK-NEXT:    [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0
; CHECK-NEXT:    call void @use32(i32 [[LOW_BITS_TO_SKIP]])
; CHECK-NEXT:    call void @use32(i32 [[HIGH_BITS_EXTRACTED]])
; CHECK-NEXT:    call void @use1(i1 [[SHOULD_SIGNEXT]])
; CHECK-NEXT:    call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]])
; CHECK-NEXT:    call void @use32(i32 [[MAGIC]])
; CHECK-NEXT:    [[SIGNEXTENDED:%.*]] = or i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]]
; CHECK-NEXT:    ret i32 [[SIGNEXTENDED]]
;
  %low_bits_to_skip = sub i32 32, %nbits
  %high_bits_extracted = lshr i32 %data, %low_bits_to_skip
  %should_signext = icmp slt i32 %data, 0
  %all_bits_except_low_nbits = shl i32 1, %nbits ; not -1
  %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0

  call void @use32(i32 %low_bits_to_skip)
  call void @use32(i32 %high_bits_extracted)
  call void @use1(i1 %should_signext)
  call void @use32(i32 %all_bits_except_low_nbits)
  call void @use32(i32 %magic)

  %signextended = or i32 %high_bits_extracted, %magic
  ret i32 %signextended
}