llvm/test/Transforms/InstCombine/gep-canonicalize-constant-indices.ll

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

; Constant-indexed GEP instructions in a chain of GEP instructions should be
; swapped to the end whenever such transformation is valid. This allows them to
; be merged.

declare void @use(i1)


; The constant-indexed GEP instruction should be swapped to the end, even
; without merging.
; result = (((ptr) p + a) + b) + 1
define ptr @basic(ptr %p, i64 %a, i64 %b) {
; CHECK-LABEL: @basic(
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 1
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i64 [[A:%.*]]
; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP2]], i64 [[B:%.*]]
; CHECK-NEXT:    ret ptr [[TMP3]]
;
  %1 = getelementptr inbounds i32, ptr %p, i64 1
  %2 = getelementptr inbounds i32, ptr %1, i64 %a
  %3 = getelementptr inbounds i32, ptr %2, i64 %b
  ret ptr %3
}

; GEP with the last index being a constant should also be swapped.
define ptr @partialConstant1(ptr %p, i64 %a, i64 %b) {
; CHECK-LABEL: @partialConstant1(
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 [[B:%.*]]
; CHECK-NEXT:    ret ptr [[TMP1]]
;
  %1 = getelementptr inbounds [4 x i32], ptr %p, i64 %a, i64 1
  %2 = getelementptr inbounds i32, ptr %p, i64 %b
  ret ptr %2
}

; Negative test. GEP should not be swapped if the last index is not a constant.
define ptr @partialConstant2(ptr %p, i64 %a, i64 %b) {
; CHECK-LABEL: @partialConstant2(
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 [[B:%.*]]
; CHECK-NEXT:    ret ptr [[TMP1]]
;
  %1 = getelementptr inbounds [4 x i32], ptr %p, i64 1, i64 %a
  %2 = getelementptr inbounds i32, ptr %p, i64 %b
  ret ptr %2
}

; Constant-indexed GEP are merged after swawpping.
; result = ((ptr) p + a) + 3
define ptr @merge(ptr %p, i64 %a) {
; CHECK-LABEL: @merge(
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 1
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i64 [[A:%.*]]
; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP2]], i64 2
; CHECK-NEXT:    ret ptr [[TMP3]]
;
  %1 = getelementptr inbounds i32, ptr %p, i64 1
  %2 = getelementptr inbounds i32, ptr %1, i64 %a
  %3 = getelementptr inbounds i32, ptr %2, i64 2
  ret ptr %3
}

; Multiple constant-indexed GEP. Note that the first two cannot be merged at
; first, but after the second and third are merged, the result can be merged
; with the first one on the next pass.
; result = (ptr) ((ptr) ((ptr) ptr + a) + (a * b)) + 9
define ptr @nested(ptr %p, i64 %a, i64 %b) {
; CHECK-LABEL: @nested(
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds <3 x i32>, ptr [[P:%.*]], i64 1
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[TMP1]], i64 [[A:%.*]]
; CHECK-NEXT:    [[TMP3:%.*]] = mul i64 [[A]], [[B:%.*]]
; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr inbounds <5 x i32>, ptr [[TMP2]], i64 4
; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i16, ptr [[TMP4]], i64 [[TMP3]]
; CHECK-NEXT:    [[TMP6:%.*]] = getelementptr inbounds <4 x i32>, ptr [[TMP5]], i64 1
; CHECK-NEXT:    ret ptr [[TMP6]]
;
  %1 = getelementptr inbounds <3 x i32>, ptr %p, i64 1
  %2 = getelementptr inbounds i8, ptr %1, i64 %a
  %3 = mul i64 %a, %b
  %4 = getelementptr inbounds <5 x i32>, ptr %2, i64 4
  %5 = getelementptr inbounds i16, ptr %4, i64 %3
  %6 = getelementptr inbounds <4 x i32>, ptr %5, i64 1
  ret ptr %6
}

; It is valid to swap if the source operand of the first GEP has multiple uses.
define ptr @multipleUses1(ptr %p) {
; CHECK-LABEL: @multipleUses1(
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 1
; CHECK-NEXT:    [[TMP2:%.*]] = ptrtoint ptr [[P]] to i64
; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i64 [[TMP2]]
; CHECK-NEXT:    ret ptr [[TMP3]]
;
  %1 = getelementptr inbounds i32, ptr %p, i64 1
  %2 = ptrtoint ptr %p to i64
  %3 = getelementptr inbounds i32, ptr %1, i64 %2
  ret ptr %3
}

; It is valid to swap if the second GEP has multiple uses.
define ptr @multipleUses2(ptr %p, i64 %a) {
; CHECK-LABEL: @multipleUses2(
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 1
; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i64 [[A:%.*]]
; CHECK-NEXT:    call void @use(ptr nonnull [[TMP2]])
; CHECK-NEXT:    ret ptr [[TMP2]]
;
  %1 = getelementptr inbounds i32, ptr %p, i64 1
  %2 = getelementptr inbounds i32, ptr %1, i64 %a
  call void @use(ptr %2)
  ret ptr %2
}

; Negative test. It is not valid to swap if the first GEP has multiple uses.
define ptr @multipleUses3(ptr %p) {
; CHECK-LABEL: @multipleUses3(
; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[P:%.*]], i64 1
; CHECK-NEXT:    [[TMP2:%.*]] = ptrtoint ptr [[TMP1]] to i64
; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i64 [[TMP2]]
; CHECK-NEXT:    ret ptr [[TMP3]]
;
  %1 = getelementptr inbounds i32, ptr %p, i64 1
  %2 = ptrtoint ptr %1 to i64
  %3 = getelementptr inbounds i32, ptr %1, i64 %2
  ret ptr %3
}