[TBAA] Use !tbaa for first accessed field if it is an exact match in offset and size. #81313
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Retain TBAAStruct if we fail to match the access to a single field. All users at the moment use this when using the full size of the original access. SROA also retains the original TBAAStruct when accessing parts at offset 0. Motivation for this and follow-on patches is to improve codegen for libc++, where using memcpy limits optimizations, like vectorization for code iteration over std::vector<std::complex<float>>: https://godbolt.org/z/f3vqYos3c Depends on #81284
If a split memory access introduced by SROA accesses precisely a single field of the original operation's !tbaa.struct, use the !tbaa tag for the accessed field directly instead of the full !tbaa.struct. InstCombine already had a similar logic. Motivation for this and follow-on patches is to improve codegen for libc++, where using memcpy limits optimizations, like vectorization for code iteration over std::vector<std::complex<float>>: https://godbolt.org/z/f3vqYos3c Depends on #81285.
Motivation for this and follow-on patches is to improve codegen for libc++, where using memcpy limits optimizations, like vectorization for code iteration over std::vector<std::complex<float>>: https://godbolt.org/z/f3vqYos3c Depends on #81289.
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@llvm/pr-subscribers-llvm-transforms @llvm/pr-subscribers-llvm-analysis Author: Florian Hahn (fhahn) ChangesMotivation for this and follow-on patches is to improve codegen for libc++, where using memcpy limits optimizations, like vectorization for code iteration over std::vector<std::complex<float>>: https://godbolt.org/z/f3vqYos3c Depends on #81289. Full diff: https://github.com/llvm/llvm-project/pull/81313.diff 3 Files Affected:
diff --git a/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp b/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
index b2dc451d581939..25ac01db7633ee 100644
--- a/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
@@ -821,8 +821,7 @@ MDNode *AAMDNodes::extendToTBAA(MDNode *MD, ssize_t Len) {
AAMDNodes AAMDNodes::adjustForAccess(unsigned AccessSize) {
AAMDNodes New = *this;
MDNode *M = New.TBAAStruct;
- if (M && M->getNumOperands() == 3 && M->getOperand(0) &&
- mdconst::hasa<ConstantInt>(M->getOperand(0)) &&
+ if (M && M->getOperand(0) && mdconst::hasa<ConstantInt>(M->getOperand(0)) &&
mdconst::extract<ConstantInt>(M->getOperand(0))->isZero() &&
M->getOperand(1) && mdconst::hasa<ConstantInt>(M->getOperand(1)) &&
mdconst::extract<ConstantInt>(M->getOperand(1))->getValue() ==
diff --git a/llvm/test/Transforms/SROA/tbaa-struct2.ll b/llvm/test/Transforms/SROA/tbaa-struct2.ll
index 02c99a2b329457..545fa47eecb2ce 100644
--- a/llvm/test/Transforms/SROA/tbaa-struct2.ll
+++ b/llvm/test/Transforms/SROA/tbaa-struct2.ll
@@ -11,11 +11,11 @@ declare double @subcall(double %g, i32 %m)
define double @bar(ptr %wishart) {
; CHECK-LABEL: @bar(
; CHECK-NEXT: [[TMP_SROA_3:%.*]] = alloca [4 x i8], align 4
-; CHECK-NEXT: [[TMP_SROA_0_0_COPYLOAD:%.*]] = load double, ptr [[WISHART:%.*]], align 8, !tbaa.struct [[TBAA_STRUCT0:![0-9]+]]
+; CHECK-NEXT: [[TMP_SROA_0_0_COPYLOAD:%.*]] = load double, ptr [[WISHART:%.*]], align 8, !tbaa [[TBAA0:![0-9]+]]
; CHECK-NEXT: [[TMP_SROA_2_0_WISHART_SROA_IDX:%.*]] = getelementptr inbounds i8, ptr [[WISHART]], i64 8
-; CHECK-NEXT: [[TMP_SROA_2_0_COPYLOAD:%.*]] = load i32, ptr [[TMP_SROA_2_0_WISHART_SROA_IDX]], align 8, !tbaa [[TBAA5:![0-9]+]]
+; CHECK-NEXT: [[TMP_SROA_2_0_COPYLOAD:%.*]] = load i32, ptr [[TMP_SROA_2_0_WISHART_SROA_IDX]], align 8, !tbaa [[TBAA4:![0-9]+]]
; CHECK-NEXT: [[TMP_SROA_3_0_WISHART_SROA_IDX:%.*]] = getelementptr inbounds i8, ptr [[WISHART]], i64 12
-; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[TMP_SROA_3]], ptr align 4 [[TMP_SROA_3_0_WISHART_SROA_IDX]], i64 4, i1 false), !tbaa.struct [[TBAA_STRUCT7:![0-9]+]]
+; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[TMP_SROA_3]], ptr align 4 [[TMP_SROA_3_0_WISHART_SROA_IDX]], i64 4, i1 false), !tbaa.struct [[TBAA_STRUCT6:![0-9]+]]
; CHECK-NEXT: [[CALL:%.*]] = call double @subcall(double [[TMP_SROA_0_0_COPYLOAD]], i32 [[TMP_SROA_2_0_COPYLOAD]])
; CHECK-NEXT: ret double [[CALL]]
;
@@ -38,14 +38,13 @@ define double @bar(ptr %wishart) {
;.
; CHECK: attributes #[[ATTR0:[0-9]+]] = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
;.
-; CHECK: [[TBAA_STRUCT0]] = !{i64 0, i64 8, [[META1:![0-9]+]], i64 8, i64 4, [[TBAA5]]}
-; CHECK: [[META1]] = !{[[META2:![0-9]+]], [[META2]], i64 0}
-; CHECK: [[META2]] = !{!"double", [[META3:![0-9]+]], i64 0}
-; CHECK: [[META3]] = !{!"omnipotent char", [[META4:![0-9]+]], i64 0}
-; CHECK: [[META4]] = !{!"Simple C++ TBAA"}
-; CHECK: [[TBAA5]] = !{[[META6:![0-9]+]], [[META6]], i64 0}
-; CHECK: [[META6]] = !{!"int", [[META3]], i64 0}
-; CHECK: [[TBAA_STRUCT7]] = !{}
+; CHECK: [[TBAA0]] = !{[[META1:![0-9]+]], [[META1]], i64 0}
+; CHECK: [[META1]] = !{!"double", [[META2:![0-9]+]], i64 0}
+; CHECK: [[META2]] = !{!"omnipotent char", [[META3:![0-9]+]], i64 0}
+; CHECK: [[META3]] = !{!"Simple C++ TBAA"}
+; CHECK: [[TBAA4]] = !{[[META5:![0-9]+]], [[META5]], i64 0}
+; CHECK: [[META5]] = !{!"int", [[META2]], i64 0}
+; CHECK: [[TBAA_STRUCT6]] = !{}
;.
;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
; CHECK-MODIFY-CFG: {{.*}}
diff --git a/llvm/test/Transforms/SROA/tbaa-struct3.ll b/llvm/test/Transforms/SROA/tbaa-struct3.ll
index 603e7d708647fc..68553d9b1a270b 100644
--- a/llvm/test/Transforms/SROA/tbaa-struct3.ll
+++ b/llvm/test/Transforms/SROA/tbaa-struct3.ll
@@ -7,9 +7,9 @@ define void @load_store_transfer_split_struct_tbaa_2_float(ptr dereferenceable(2
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = bitcast float [[A]] to i32
; CHECK-NEXT: [[TMP1:%.*]] = bitcast float [[B]] to i32
-; CHECK-NEXT: store i32 [[TMP0]], ptr [[RES]], align 4, !tbaa.struct [[TBAA_STRUCT0:![0-9]+]]
+; CHECK-NEXT: store i32 [[TMP0]], ptr [[RES]], align 4, !tbaa [[TBAA0:![0-9]+]]
; CHECK-NEXT: [[RES_SROA_IDX:%.*]] = getelementptr inbounds i8, ptr [[RES]], i64 4
-; CHECK-NEXT: store i32 [[TMP1]], ptr [[RES_SROA_IDX]], align 4, !tbaa [[TBAA1:![0-9]+]]
+; CHECK-NEXT: store i32 [[TMP1]], ptr [[RES_SROA_IDX]], align 4, !tbaa [[TBAA0]]
; CHECK-NEXT: [[P:%.*]] = load ptr, ptr [[RES]], align 8
; CHECK-NEXT: ret void
;
@@ -29,9 +29,9 @@ define void @memcpy_transfer(ptr dereferenceable(24) %res, float %a, float %b) {
; CHECK-SAME: ptr dereferenceable(24) [[RES:%.*]], float [[A:%.*]], float [[B:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[L_PTR:%.*]] = load ptr, ptr [[RES]], align 8
-; CHECK-NEXT: store float [[A]], ptr [[L_PTR]], align 1, !tbaa.struct [[TBAA_STRUCT0]]
+; CHECK-NEXT: store float [[A]], ptr [[L_PTR]], align 1, !tbaa [[TBAA0]]
; CHECK-NEXT: [[TMP_SROA_2_0_L_PTR_SROA_IDX:%.*]] = getelementptr inbounds i8, ptr [[L_PTR]], i64 4
-; CHECK-NEXT: store float [[B]], ptr [[TMP_SROA_2_0_L_PTR_SROA_IDX]], align 1, !tbaa [[TBAA1]]
+; CHECK-NEXT: store float [[B]], ptr [[TMP_SROA_2_0_L_PTR_SROA_IDX]], align 1, !tbaa [[TBAA0]]
; CHECK-NEXT: ret void
;
entry:
@@ -49,11 +49,11 @@ define void @memcpy_transfer_tbaa_field_and_size_do_not_align(ptr dereferenceabl
; CHECK-SAME: ptr dereferenceable(24) [[RES:%.*]], float [[A:%.*]], float [[B:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[L_PTR:%.*]] = load ptr, ptr [[RES]], align 8
-; CHECK-NEXT: store float [[A]], ptr [[L_PTR]], align 1, !tbaa.struct [[TBAA_STRUCT0]]
+; CHECK-NEXT: store float [[A]], ptr [[L_PTR]], align 1, !tbaa [[TBAA0]]
; CHECK-NEXT: [[TMP_SROA_2_0_L_PTR_SROA_IDX:%.*]] = getelementptr inbounds i8, ptr [[L_PTR]], i64 4
; CHECK-NEXT: [[TMP0:%.*]] = bitcast float [[B]] to i32
; CHECK-NEXT: [[TMP_SROA_2_0_EXTRACT_TRUNC:%.*]] = trunc i32 [[TMP0]] to i16
-; CHECK-NEXT: store i16 [[TMP_SROA_2_0_EXTRACT_TRUNC]], ptr [[TMP_SROA_2_0_L_PTR_SROA_IDX]], align 1, !tbaa.struct [[TBAA_STRUCT5:![0-9]+]]
+; CHECK-NEXT: store i16 [[TMP_SROA_2_0_EXTRACT_TRUNC]], ptr [[TMP_SROA_2_0_L_PTR_SROA_IDX]], align 1, !tbaa.struct [[TBAA_STRUCT4:![0-9]+]]
; CHECK-NEXT: ret void
;
entry:
@@ -74,8 +74,8 @@ define void @load_store_transfer_split_struct_tbaa_2_i31(ptr dereferenceable(24)
; CHECK-NEXT: store i31 [[A]], ptr [[TMP]], align 4
; CHECK-NEXT: [[TMP_4_TMP_4_SROA_IDX:%.*]] = getelementptr inbounds i8, ptr [[TMP]], i64 4
; CHECK-NEXT: store i31 [[B]], ptr [[TMP_4_TMP_4_SROA_IDX]], align 4
-; CHECK-NEXT: [[TMP_0_L1:%.*]] = load i62, ptr [[TMP]], align 4, !tbaa.struct [[TBAA_STRUCT0]]
-; CHECK-NEXT: store i62 [[TMP_0_L1]], ptr [[RES]], align 4, !tbaa.struct [[TBAA_STRUCT0]]
+; CHECK-NEXT: [[TMP_0_L1:%.*]] = load i62, ptr [[TMP]], align 4, !tbaa.struct [[TBAA_STRUCT5:![0-9]+]]
+; CHECK-NEXT: store i62 [[TMP_0_L1]], ptr [[RES]], align 4, !tbaa.struct [[TBAA_STRUCT5]]
; CHECK-NEXT: ret void
;
entry:
@@ -98,10 +98,10 @@ declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias
!3 = !{!"omnipotent char", !4, i64 0}
!4 = !{!"Simple C++ TBAA"}
;.
-; CHECK: [[TBAA_STRUCT0]] = !{i64 0, i64 4, [[TBAA1]], i64 4, i64 4, [[TBAA1]]}
-; CHECK: [[TBAA1]] = !{[[META2:![0-9]+]], [[META2]], i64 0}
-; CHECK: [[META2]] = !{!"float", [[META3:![0-9]+]], i64 0}
-; CHECK: [[META3]] = !{!"omnipotent char", [[META4:![0-9]+]], i64 0}
-; CHECK: [[META4]] = !{!"Simple C++ TBAA"}
-; CHECK: [[TBAA_STRUCT5]] = !{i64 0, i64 4, [[TBAA1]]}
+; CHECK: [[TBAA0]] = !{[[META1:![0-9]+]], [[META1]], i64 0}
+; CHECK: [[META1]] = !{!"float", [[META2:![0-9]+]], i64 0}
+; CHECK: [[META2]] = !{!"omnipotent char", [[META3:![0-9]+]], i64 0}
+; CHECK: [[META3]] = !{!"Simple C++ TBAA"}
+; CHECK: [[TBAA_STRUCT4]] = !{i64 0, i64 4, [[TBAA0]]}
+; CHECK: [[TBAA_STRUCT5]] = !{i64 0, i64 4, [[TBAA0]], i64 4, i64 4, [[TBAA0]]}
;.
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dobbelaj-snps
approved these changes
Feb 12, 2024
fhahn
changed the title
Base automatically changed from
users/fhahn/sroa-use-tbaa-for-matching-field-access
to
main
February 16, 2024 13:45
…w-multiple-fields Conflicts: llvm/include/llvm/IR/Metadata.h llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp llvm/lib/Transforms/Scalar/SROA.cpp llvm/test/Transforms/SROA/tbaa-struct2.ll llvm/test/Transforms/SROA/tbaa-struct3.ll
This was referenced Feb 22, 2024
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Mar 1, 2024
Add tests to cover missing cases for llvm#81289 and llvm#81313. (cherry-picked from 2a9b86c)
fhahn
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Mar 1, 2024
…offset and size. (llvm#81313) Motivation for this and follow-on patches is to improve codegen for libc++, where using memcpy limits optimizations, like vectorization for code iteration over std::vector<std::complex<float>>: https://godbolt.org/z/f3vqYos3c Depends on llvm#81289. PR: llvm#81313 (cherry-picked from dc85719)
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Motivation for this and follow-on patches is to improve codegen for libc++, where using memcpy limits optimizations, like vectorization for code iteration over std::vector<std::complex>: https://godbolt.org/z/f3vqYos3c
Depends on #81289.