Author: Jameson Nash Date: 2021-11-10T09:50:50-08:00 New Revision: 32bb956916e3229bb060b12d7381cebc6fd05903
URL: https://github.com/llvm/llvm-project/commit/32bb956916e3229bb060b12d7381cebc6fd05903 DIFF: https://github.com/llvm/llvm-project/commit/32bb956916e3229bb060b12d7381cebc6fd05903.diff LOG: Bad SLPVectorization shufflevector replacement, resulting in write to wrong memory location We see that it might otherwise do: %10 = getelementptr {}**, <2 x {}***> %9, <2 x i32> <i32 10, i32 4> %11 = bitcast <2 x {}***> %10 to <2 x i64*> ... %27 = extractelement <2 x i64*> %11, i32 0 %28 = bitcast i64* %27 to <2 x i64>* store <2 x i64> %22, <2 x i64>* %28, align 4, !tbaa !2 Which is an out-of-bounds store (the extractelement got offset 10 instead of offset 4 as intended). With the fix, we correctly generate extractelement for i32 1 and generate correct code. Differential Revision: https://reviews.llvm.org/D106613 (cherry picked from commit e27a6db5298f6ba3c1dbc8bab25c769cfa761b2a) Added: Modified: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp llvm/test/Transforms/SLPVectorizer/X86/extract_in_tree_user.ll Removed: ################################################################################ diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp index cc3f5c7d4b481..1d06bc7d79a7e 100644 --- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp +++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp @@ -5430,8 +5430,11 @@ Value *BoUpSLP::vectorizeTree(TreeEntry *E) { // The pointer operand uses an in-tree scalar so we add the new BitCast // to ExternalUses list to make sure that an extract will be generated // in the future. - if (getTreeEntry(PO)) - ExternalUses.emplace_back(PO, cast<User>(VecPtr), 0); + if (TreeEntry *Entry = getTreeEntry(PO)) { + // Find which lane we need to extract. + unsigned FoundLane = Entry->findLaneForValue(PO); + ExternalUses.emplace_back(PO, cast<User>(VecPtr), FoundLane); + } NewLI = Builder.CreateAlignedLoad(VecTy, VecPtr, LI->getAlign()); } else { @@ -5474,8 +5477,12 @@ Value *BoUpSLP::vectorizeTree(TreeEntry *E) { // The pointer operand uses an in-tree scalar, so add the new BitCast to // ExternalUses to make sure that an extract will be generated in the // future. - if (getTreeEntry(ScalarPtr)) - ExternalUses.push_back(ExternalUser(ScalarPtr, cast<User>(VecPtr), 0)); + if (TreeEntry *Entry = getTreeEntry(ScalarPtr)) { + // Find which lane we need to extract. + unsigned FoundLane = Entry->findLaneForValue(ScalarPtr); + ExternalUses.push_back( + ExternalUser(ScalarPtr, cast<User>(VecPtr), FoundLane)); + } Value *V = propagateMetadata(ST, E->Scalars); @@ -5577,8 +5584,14 @@ Value *BoUpSLP::vectorizeTree(TreeEntry *E) { // The scalar argument uses an in-tree scalar so we add the new vectorized // call to ExternalUses list to make sure that an extract will be // generated in the future. - if (ScalarArg && getTreeEntry(ScalarArg)) - ExternalUses.push_back(ExternalUser(ScalarArg, cast<User>(V), 0)); + if (ScalarArg) { + if (TreeEntry *Entry = getTreeEntry(ScalarArg)) { + // Find which lane we need to extract. + unsigned FoundLane = Entry->findLaneForValue(ScalarArg); + ExternalUses.push_back( + ExternalUser(ScalarArg, cast<User>(V), FoundLane)); + } + } propagateIRFlags(V, E->Scalars, VL0); ShuffleBuilder.addMask(E->ReuseShuffleIndices); diff --git a/llvm/test/Transforms/SLPVectorizer/X86/extract_in_tree_user.ll b/llvm/test/Transforms/SLPVectorizer/X86/extract_in_tree_user.ll index 2348b5ae56fb4..cbf6d8ff4fa95 100644 --- a/llvm/test/Transforms/SLPVectorizer/X86/extract_in_tree_user.ll +++ b/llvm/test/Transforms/SLPVectorizer/X86/extract_in_tree_user.ll @@ -108,10 +108,9 @@ define void @externally_used_ptrs() { ; CHECK-NEXT: [[TMP3:%.*]] = getelementptr i64, <2 x i64*> [[TMP2]], <2 x i64> <i64 56, i64 11> ; CHECK-NEXT: [[TMP4:%.*]] = ptrtoint <2 x i64*> [[TMP3]] to <2 x i64> ; CHECK-NEXT: [[ARRAYIDX2:%.*]] = getelementptr inbounds i64, i64* [[TMP0]], i64 12 -; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i64*> [[TMP3]], i32 0 +; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i64*> [[TMP3]], i32 1 ; CHECK-NEXT: [[TMP6:%.*]] = bitcast i64* [[TMP5]] to <2 x i64>* ; CHECK-NEXT: [[TMP7:%.*]] = load <2 x i64>, <2 x i64>* [[TMP6]], align 8 -; CHECK-NEXT: [[TMP8:%.*]] = extractelement <2 x i64*> [[TMP3]], i32 1 ; CHECK-NEXT: [[TMP9:%.*]] = add <2 x i64> [[TMP4]], [[TMP7]] ; CHECK-NEXT: [[TMP10:%.*]] = bitcast i64* [[TMP5]] to <2 x i64>* ; CHECK-NEXT: store <2 x i64> [[TMP9]], <2 x i64>* [[TMP10]], align 8 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
