test/Transforms/InstCombine/fold-bmi.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -passes=instcombine -S < %s | FileCheck %s

; Test folding of ~x | (x - 1) to ~(x & -x)

define i64 @fold_or_not_dec(i64 %x) {
; CHECK-LABEL: define i64 @fold_or_not_dec(
; CHECK-SAME: i64 [[X:%.*]]) {
; CHECK-NEXT:    [[TMP1:%.*]] = sub i64 0, [[X]]
; CHECK-NEXT:    [[AND:%.*]] = and i64 [[X]], [[TMP1]]
; CHECK-NEXT:    [[NOT:%.*]] = xor i64 [[AND]], -1
; CHECK-NEXT:    ret i64 [[NOT]]
;
  %xor = xor i64 %x, -1
  %add = add i64 %x, -1
  %or  = or i64 %xor, %add
  ret i64 %or
}

define i64 @fold_or_dec_not(i64 %x) {
; CHECK-LABEL: define i64 @fold_or_dec_not(
; CHECK-SAME: i64 [[X:%.*]]) {
; CHECK-NEXT:    [[TMP1:%.*]] = sub i64 0, [[X]]
; CHECK-NEXT:    [[TMP2:%.*]] = and i64 [[X]], [[TMP1]]
; CHECK-NEXT:    [[OR:%.*]] = xor i64 [[TMP2]], -1
; CHECK-NEXT:    ret i64 [[OR]]
;
  %xor = xor i64 %x, -1
  %add = add i64 %x, -1
  %or  = or i64 %add, %xor
  ret i64 %or
}


; NEGATIVE TEST: add has multiple uses
define i64 @negative_multiuse_add(i64 %x, ptr %p) {
; CHECK-LABEL: define i64 @negative_multiuse_add(
; CHECK-SAME: i64 [[X:%.*]], ptr [[P:%.*]]) {
; CHECK-NEXT:    [[XOR:%.*]] = xor i64 [[X]], -1
; CHECK-NEXT:    [[ADD:%.*]] = add i64 [[X]], -1
; CHECK-NEXT:    store i64 [[ADD]], ptr [[P]], align 4
; CHECK-NEXT:    [[OR:%.*]] = or i64 [[ADD]], [[XOR]]
; CHECK-NEXT:    ret i64 [[OR]]
;
  %xor = xor i64 %x, -1
  %add = add i64 %x, -1
  store i64 %add, ptr %p     ; second use of %add
  %or  = or i64 %add, %xor
  ret i64 %or
}

; NEGATIVE TEST: xor has multiple uses
define i64 @negative_multiuse_xor(i64 %x, ptr %p) {
; CHECK-LABEL: define i64 @negative_multiuse_xor(
; CHECK-SAME: i64 [[X:%.*]], ptr [[P:%.*]]) {
; CHECK-NEXT:    [[XOR:%.*]] = xor i64 [[X]], -1
; CHECK-NEXT:    [[ADD:%.*]] = add i64 [[X]], -1
; CHECK-NEXT:    store i64 [[XOR]], ptr [[P]], align 4
; CHECK-NEXT:    [[OR:%.*]] = or i64 [[ADD]], [[XOR]]
; CHECK-NEXT:    ret i64 [[OR]]
;
  %xor = xor i64 %x, -1
  %add = add i64 %x, -1
  store i64 %xor, ptr %p     ; second use of %xor
  %or  = or i64 %add, %xor
  ret i64 %or
}