Index: cfe/trunk/lib/CodeGen/CGExpr.cpp =================================================================== --- cfe/trunk/lib/CodeGen/CGExpr.cpp +++ cfe/trunk/lib/CodeGen/CGExpr.cpp @@ -1432,11 +1432,12 @@ Load->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node); } if (TBAAInfo) { - llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo, - TBAAOffset); - if (TBAAPath) - CGM.DecorateInstructionWithTBAA(Load, TBAAPath, - false /*ConvertTypeToTag*/); + bool MayAlias = BaseInfo.getMayAlias(); + llvm::MDNode *TBAA = MayAlias + ? CGM.getTBAAInfo(getContext().CharTy) + : CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo, TBAAOffset); + if (TBAA) + CGM.DecorateInstructionWithTBAA(Load, TBAA, MayAlias); } if (EmitScalarRangeCheck(Load, Ty, Loc)) { @@ -1522,11 +1523,12 @@ Store->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node); } if (TBAAInfo) { - llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo, - TBAAOffset); - if (TBAAPath) - CGM.DecorateInstructionWithTBAA(Store, TBAAPath, - false /*ConvertTypeToTag*/); + bool MayAlias = BaseInfo.getMayAlias(); + llvm::MDNode *TBAA = MayAlias + ? CGM.getTBAAInfo(getContext().CharTy) + : CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo, TBAAOffset); + if (TBAA) + CGM.DecorateInstructionWithTBAA(Store, TBAA, MayAlias); } } @@ -3535,6 +3537,11 @@ getFieldAlignmentSource(BaseInfo.getAlignmentSource()); LValueBaseInfo FieldBaseInfo(fieldAlignSource, BaseInfo.getMayAlias()); + const RecordDecl *rec = field->getParent(); + if (rec->isUnion() || rec->hasAttr()) + FieldBaseInfo.setMayAlias(true); + bool mayAlias = FieldBaseInfo.getMayAlias(); + if (field->isBitField()) { const CGRecordLayout &RL = CGM.getTypes().getCGRecordLayout(field->getParent()); @@ -3556,11 +3563,7 @@ return LValue::MakeBitfield(Addr, Info, fieldType, FieldBaseInfo); } - const RecordDecl *rec = field->getParent(); QualType type = field->getType(); - - bool mayAlias = rec->hasAttr(); - Address addr = base.getAddress(); unsigned cvr = base.getVRQualifiers(); bool TBAAPath = CGM.getCodeGenOpts().StructPathTBAA; Index: cfe/trunk/test/CodeGen/union-tbaa1.c =================================================================== --- cfe/trunk/test/CodeGen/union-tbaa1.c +++ cfe/trunk/test/CodeGen/union-tbaa1.c @@ -0,0 +1,44 @@ +// RUN: %clang_cc1 %s -triple hexagon-unknown-elf -O2 -emit-llvm -o - | FileCheck %s + +typedef union __attribute__((aligned(4))) { + unsigned short uh[2]; + unsigned uw; +} vect32; + +void bar(vect32 p[][2]); + +// CHECK-LABEL: define void @fred +void fred(unsigned Num, int Vec[2], int *Index, int Arr[4][2]) { + vect32 Tmp[4][2]; +// Generate tbaa for the load of Index: +// CHECK: load i32, i32* %Index{{.*}}tbaa +// But no tbaa for the two stores: +// CHECK: %uw[[UW1:[0-9]*]] = getelementptr +// CHECK: store{{.*}}%uw[[UW1]] +// CHECK: tbaa ![[OCPATH:[0-9]+]] +// There will be a load after the store, and it will use tbaa. Make sure +// the check-not above doesn't find it: +// CHECK: load + Tmp[*Index][0].uw = Arr[*Index][0] * Num; +// CHECK: %uw[[UW2:[0-9]*]] = getelementptr +// CHECK: store{{.*}}%uw[[UW2]] +// CHECK: tbaa ![[OCPATH]] + Tmp[*Index][1].uw = Arr[*Index][1] * Num; +// Same here, don't generate tbaa for the loads: +// CHECK: %uh[[UH1:[0-9]*]] = bitcast %union.vect32 +// CHECK: %arrayidx[[AX1:[0-9]*]] = getelementptr{{.*}}%uh[[UH1]] +// CHECK: load i16, i16* %arrayidx[[AX1]] +// CHECK: tbaa ![[OCPATH]] +// CHECK: store + Vec[0] = Tmp[*Index][0].uh[1]; +// CHECK: %uh[[UH2:[0-9]*]] = bitcast %union.vect32 +// CHECK: %arrayidx[[AX2:[0-9]*]] = getelementptr{{.*}}%uh[[UH2]] +// CHECK: load i16, i16* %arrayidx[[AX2]] +// CHECK: tbaa ![[OCPATH]] +// CHECK: store + Vec[1] = Tmp[*Index][1].uh[1]; + bar(Tmp); +} + +// CHECK-DAG: ![[CHAR:[0-9]+]] = !{!"omnipotent char" +// CHECK-DAG: ![[OCPATH]] = !{![[CHAR]], ![[CHAR]], i64 0} Index: cfe/trunk/test/CodeGenCXX/union-tbaa2.cpp =================================================================== --- cfe/trunk/test/CodeGenCXX/union-tbaa2.cpp +++ cfe/trunk/test/CodeGenCXX/union-tbaa2.cpp @@ -0,0 +1,45 @@ +// RUN: %clang_cc1 %s -O2 -std=c++11 -triple x86_64-unknown-linux-gnu -target-cpu x86-64 -target-feature +sse4.2 -target-feature +avx -emit-llvm -o - | FileCheck %s + +// Testcase from llvm.org/PR32056 + +extern "C" int printf (const char *__restrict __format, ...); + +typedef double __m256d __attribute__((__vector_size__(32))); + +static __inline __m256d __attribute__((__always_inline__, __nodebug__, + __target__("avx"))) +_mm256_setr_pd(double __a, double __b, double __c, double __d) { + return (__m256d){ __a, __b, __c, __d }; +} + +struct A { + A () { +// Check that the TBAA information generated for the stores to the +// union members is based on the omnipotent char. +// CHECK: store <4 x double> +// CHECK: tbaa ![[OCPATH:[0-9]+]] +// CHECK: store <4 x double> +// CHECK: tbaa ![[OCPATH]] +// CHECK: call + a = _mm256_setr_pd(0.0, 1.0, 2.0, 3.0); + b = _mm256_setr_pd(4.0, 5.0, 6.0, 7.0); + } + + const double *begin() { return c; } + const double *end() { return c+8; } + + union { + struct { __m256d a, b; }; + double c[8]; + }; +}; + +int main(int argc, char *argv[]) { + A a; + for (double value : a) + printf("%f ", value); + return 0; +} + +// CHECK-DAG: ![[CHAR:[0-9]+]] = !{!"omnipotent char" +// CHECK-DAG: ![[OCPATH]] = !{![[CHAR]], ![[CHAR]], i64 0}