llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/fence-noalias-metadata.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -mtriple=amdgpu-amd-amdhsa -aa-pipeline=basic-aa,scoped-noalias-aa -passes=load-store-vectorizer -S -o - %s | FileCheck %s

; Test that getModRefInfo(FenceInst, Loc) uses scoped noalias metadata on the
; fence to prove it cannot affect a given memory location. Without this, the
; load-store vectorizer conservatively treats fences as potential clobbers,
; preventing vectorization of adjacent loads across fences.
;
; This models what happens after AMDGPULowerKernelArguments: noalias kernel
; pointer arguments are replaced with loads from the kernarg segment, losing
; the readonly attribute. The !alias.scope/!noalias metadata partially
; compensates, but getModRefInfo(FenceInst) did not check it.

; Positive: fence declares !noalias for the load's scope -> vectorization.
define void @vectorize_loads_across_fence_with_noalias(ptr addrspace(1) %ptr) {
; CHECK-LABEL: define void @vectorize_loads_across_fence_with_noalias(
; CHECK-SAME: ptr addrspace(1) [[PTR:%.*]]) {
; CHECK-NEXT:    [[TMP1:%.*]] = load <2 x i32>, ptr addrspace(1) [[PTR]], align 8, !alias.scope [[META0:![0-9]+]], !noalias [[META3:![0-9]+]]
; CHECK-NEXT:    [[LOAD01:%.*]] = extractelement <2 x i32> [[TMP1]], i64 0
; CHECK-NEXT:    [[LOAD12:%.*]] = extractelement <2 x i32> [[TMP1]], i64 1
; CHECK-NEXT:    fence syncscope("workgroup") release, !noalias [[META5:![0-9]+]]
; CHECK-NEXT:    fence syncscope("workgroup") acquire, !noalias [[META5]]
; CHECK-NEXT:    [[SUM:%.*]] = add i32 [[LOAD01]], [[LOAD12]]
; CHECK-NEXT:    call void @use(i32 [[SUM]])
; CHECK-NEXT:    ret void
;
  %gep1 = getelementptr i32, ptr addrspace(1) %ptr, i64 1
  %load0 = load i32, ptr addrspace(1) %ptr, align 8, !alias.scope !0, !noalias !3
  fence syncscope("workgroup") release, !noalias !5
  fence syncscope("workgroup") acquire, !noalias !5
  %load1 = load i32, ptr addrspace(1) %gep1, align 4, !alias.scope !0, !noalias !3
  %sum = add i32 %load0, %load1
  call void @use(i32 %sum)
  ret void
}

; Positive: fence declares !alias.scope, load declares !noalias covering that
; scope. Exercises the symmetric branch in ScopedNoAliasAA::getModRefInfo.
define void @vectorize_loads_across_fence_with_alias_scope(ptr addrspace(1) %ptr) {
; CHECK-LABEL: define void @vectorize_loads_across_fence_with_alias_scope(
; CHECK-SAME: ptr addrspace(1) [[PTR:%.*]]) {
; CHECK-NEXT:    [[TMP1:%.*]] = load <2 x i32>, ptr addrspace(1) [[PTR]], align 8, !alias.scope [[META0]], !noalias [[META6:![0-9]+]]
; CHECK-NEXT:    [[LOAD01:%.*]] = extractelement <2 x i32> [[TMP1]], i64 0
; CHECK-NEXT:    [[LOAD12:%.*]] = extractelement <2 x i32> [[TMP1]], i64 1
; CHECK-NEXT:    fence syncscope("workgroup") release, !alias.scope [[META6]]
; CHECK-NEXT:    fence syncscope("workgroup") acquire, !alias.scope [[META6]]
; CHECK-NEXT:    [[SUM:%.*]] = add i32 [[LOAD01]], [[LOAD12]]
; CHECK-NEXT:    call void @use(i32 [[SUM]])
; CHECK-NEXT:    ret void
;
  %gep1 = getelementptr i32, ptr addrspace(1) %ptr, i64 1
  %load0 = load i32, ptr addrspace(1) %ptr, align 8, !alias.scope !0, !noalias !7
  fence syncscope("workgroup") release, !alias.scope !7
  fence syncscope("workgroup") acquire, !alias.scope !7
  %load1 = load i32, ptr addrspace(1) %gep1, align 4, !alias.scope !0, !noalias !7
  %sum = add i32 %load0, %load1
  call void @use(i32 %sum)
  ret void
}

; Negative: no metadata on fence at all -> no vectorization.
define void @no_vectorize_loads_across_fence_without_noalias(ptr addrspace(1) %ptr) {
; CHECK-LABEL: define void @no_vectorize_loads_across_fence_without_noalias(
; CHECK-SAME: ptr addrspace(1) [[PTR:%.*]]) {
; CHECK-NEXT:    [[GEP1:%.*]] = getelementptr i32, ptr addrspace(1) [[PTR]], i64 1
; CHECK-NEXT:    [[LOAD0:%.*]] = load i32, ptr addrspace(1) [[PTR]], align 8, !alias.scope [[META0]], !noalias [[META3]]
; CHECK-NEXT:    fence syncscope("workgroup") release
; CHECK-NEXT:    fence syncscope("workgroup") acquire
; CHECK-NEXT:    [[LOAD1:%.*]] = load i32, ptr addrspace(1) [[GEP1]], align 4, !alias.scope [[META0]], !noalias [[META3]]
; CHECK-NEXT:    [[SUM:%.*]] = add i32 [[LOAD0]], [[LOAD1]]
; CHECK-NEXT:    call void @use(i32 [[SUM]])
; CHECK-NEXT:    ret void
;
  %gep1 = getelementptr i32, ptr addrspace(1) %ptr, i64 1
  %load0 = load i32, ptr addrspace(1) %ptr, align 8, !alias.scope !0, !noalias !3
  fence syncscope("workgroup") release
  fence syncscope("workgroup") acquire
  %load1 = load i32, ptr addrspace(1) %gep1, align 4, !alias.scope !0, !noalias !3
  %sum = add i32 %load0, %load1
  call void @use(i32 %sum)
  ret void
}

; Negative: fence has !noalias but only for a different scope (other_arg_scope),
; not the load's scope (arg_scope). Partial coverage does not help.
define void @no_vectorize_loads_across_fence_with_partial_noalias(ptr addrspace(1) %ptr) {
; CHECK-LABEL: define void @no_vectorize_loads_across_fence_with_partial_noalias(
; CHECK-SAME: ptr addrspace(1) [[PTR:%.*]]) {
; CHECK-NEXT:    [[GEP1:%.*]] = getelementptr i32, ptr addrspace(1) [[PTR]], i64 1
; CHECK-NEXT:    [[LOAD0:%.*]] = load i32, ptr addrspace(1) [[PTR]], align 8, !alias.scope [[META0]], !noalias [[META3]]
; CHECK-NEXT:    fence syncscope("workgroup") release, !noalias [[META3]]
; CHECK-NEXT:    fence syncscope("workgroup") acquire, !noalias [[META3]]
; CHECK-NEXT:    [[LOAD1:%.*]] = load i32, ptr addrspace(1) [[GEP1]], align 4, !alias.scope [[META0]], !noalias [[META3]]
; CHECK-NEXT:    [[SUM:%.*]] = add i32 [[LOAD0]], [[LOAD1]]
; CHECK-NEXT:    call void @use(i32 [[SUM]])
; CHECK-NEXT:    ret void
;
  %gep1 = getelementptr i32, ptr addrspace(1) %ptr, i64 1
  %load0 = load i32, ptr addrspace(1) %ptr, align 8, !alias.scope !0, !noalias !3
  fence syncscope("workgroup") release, !noalias !3
  fence syncscope("workgroup") acquire, !noalias !3
  %load1 = load i32, ptr addrspace(1) %gep1, align 4, !alias.scope !0, !noalias !3
  %sum = add i32 %load0, %load1
  call void @use(i32 %sum)
  ret void
}

declare void @use(i32)

; Metadata: three noalias scopes in the same domain.
!0 = !{!1}
!1 = distinct !{!1, !2, !"arg_scope"}
!2 = distinct !{!2, !"kernel_domain"}
!3 = !{!4}
!4 = distinct !{!4, !2, !"other_arg_scope"}
!5 = !{!1, !4}
!6 = distinct !{!6, !2, !"fence_sync_scope"}
!7 = !{!6}
;.
; CHECK: [[META0]] = !{[[META1:![0-9]+]]}
; CHECK: [[META1]] = distinct !{[[META1]], [[META2:![0-9]+]], !"arg_scope"}
; CHECK: [[META2]] = distinct !{[[META2]], !"kernel_domain"}
; CHECK: [[META3]] = !{[[META4:![0-9]+]]}
; CHECK: [[META4]] = distinct !{[[META4]], [[META2]], !"other_arg_scope"}
; CHECK: [[META5]] = !{[[META1]], [[META4]]}
; CHECK: [[META6]] = !{[[META7:![0-9]+]]}
; CHECK: [[META7]] = distinct !{[[META7]], [[META2]], !"fence_sync_scope"}
;.