From 324d641b75b54a8772c3c9a881eedad62dc5518c Mon Sep 17 00:00:00 2001 From: =?utf8?q?D=C3=A1vid=20Bolvansk=C3=BD?= Date: Tue, 20 Apr 2021 02:03:38 +0200 Subject: [PATCH] [InstCombine] Enhance deduction of alignment for aligned_alloc This patch improves https://reviews.llvm.org/D76971 (Deduce attributes for aligned_alloc in InstCombine) and implements "TODO" item mentioned in the review of that patch. > The function aligned_alloc() is the same as memalign(), except for the added restriction that size should be a multiple of alignment. Currently, we simply bail out if we see a non-constant size - change that. Reviewed By: jdoerfert Differential Revision: https://reviews.llvm.org/D100785 --- .../Transforms/InstCombine/InstCombineCalls.cpp | 14 +++++----- .../Transforms/InstCombine/InstCombineInternal.h | 1 + .../test/Transforms/InstCombine/deref-alloc-fns.ll | 30 +++++++++++++++++++--- 3 files changed, 36 insertions(+), 9 deletions(-) diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp index 615f10e1..3932446 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp @@ -2049,7 +2049,7 @@ static IntrinsicInst *findInitTrampoline(Value *Callee) { return nullptr; } -static void annotateAnyAllocSite(CallBase &Call, const TargetLibraryInfo *TLI) { +void InstCombinerImpl::annotateAnyAllocSite(CallBase &Call, const TargetLibraryInfo *TLI) { unsigned NumArgs = Call.getNumArgOperands(); ConstantInt *Op0C = dyn_cast(Call.getOperand(0)); ConstantInt *Op1C = @@ -2068,12 +2068,14 @@ static void annotateAnyAllocSite(CallBase &Call, const TargetLibraryInfo *TLI) { Call.addAttribute(AttributeList::ReturnIndex, Attribute::getWithDereferenceableOrNullBytes( Call.getContext(), Op0C->getZExtValue())); - } else if (isAlignedAllocLikeFn(&Call, TLI) && Op1C) { - Call.addAttribute(AttributeList::ReturnIndex, - Attribute::getWithDereferenceableOrNullBytes( - Call.getContext(), Op1C->getZExtValue())); + } else if (isAlignedAllocLikeFn(&Call, TLI)) { + if (Op1C) + Call.addAttribute(AttributeList::ReturnIndex, + Attribute::getWithDereferenceableOrNullBytes( + Call.getContext(), Op1C->getZExtValue())); // Add alignment attribute if alignment is a power of two constant. - if (Op0C && Op0C->getValue().ult(llvm::Value::MaximumAlignment)) { + if (Op0C && Op0C->getValue().ult(llvm::Value::MaximumAlignment) && + isKnownNonZero(Call.getOperand(1), DL, 0, &AC, &Call, &DT)) { uint64_t AlignmentVal = Op0C->getZExtValue(); if (llvm::isPowerOf2_64(AlignmentVal)) Call.addAttribute(AttributeList::ReturnIndex, diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h index 8907d4b..edf8f0f 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h +++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h @@ -187,6 +187,7 @@ public: const Twine &Suffix = ""); private: + void annotateAnyAllocSite(CallBase &Call, const TargetLibraryInfo *TLI); bool shouldChangeType(unsigned FromBitWidth, unsigned ToBitWidth) const; bool shouldChangeType(Type *From, Type *To) const; Value *dyn_castNegVal(Value *V) const; diff --git a/llvm/test/Transforms/InstCombine/deref-alloc-fns.ll b/llvm/test/Transforms/InstCombine/deref-alloc-fns.ll index 2726a5f..b660e6b 100644 --- a/llvm/test/Transforms/InstCombine/deref-alloc-fns.ll +++ b/llvm/test/Transforms/InstCombine/deref-alloc-fns.ll @@ -38,13 +38,37 @@ define noalias i8* @aligned_alloc_constant_size() { ret i8* %call } +define noalias i8* @aligned_alloc_unknown_size_nonzero(i1 %c) { +; CHECK-LABEL: @aligned_alloc_unknown_size_nonzero( +; CHECK-NEXT: [[SIZE:%.*]] = select i1 [[C:%.*]], i64 64, i64 128 +; CHECK-NEXT: [[CALL:%.*]] = tail call noalias align 32 i8* @aligned_alloc(i64 32, i64 [[SIZE]]) +; CHECK-NEXT: ret i8* [[CALL]] +; + %size = select i1 %c, i64 64, i64 128 + %call = tail call noalias i8* @aligned_alloc(i64 32, i64 %size) + ret i8* %call +} + +define noalias i8* @aligned_alloc_unknown_size_possibly_zero(i1 %c) { +; CHECK-LABEL: @aligned_alloc_unknown_size_possibly_zero( +; CHECK-NEXT: [[SIZE:%.*]] = select i1 [[C:%.*]], i64 64, i64 0 +; CHECK-NEXT: [[CALL:%.*]] = tail call noalias i8* @aligned_alloc(i64 32, i64 [[SIZE]]) +; CHECK-NEXT: ret i8* [[CALL]] +; + %size = select i1 %c, i64 64, i64 0 + %call = tail call noalias i8* @aligned_alloc(i64 32, i64 %size) + ret i8* %call +} + declare noalias i8* @foo(i8*, i8*, i8*) define noalias i8* @aligned_alloc_dynamic_args(i64 %align, i64 %size) { ; CHECK-LABEL: @aligned_alloc_dynamic_args( -; CHECK-NEXT: tail call noalias dereferenceable_or_null(1024) i8* @aligned_alloc(i64 %{{.*}}, i64 1024) -; CHECK-NEXT: tail call noalias i8* @aligned_alloc(i64 0, i64 1024) -; CHECK-NEXT: tail call noalias i8* @aligned_alloc(i64 32, i64 %{{.*}}) +; CHECK-NEXT: [[CALL:%.*]] = tail call noalias dereferenceable_or_null(1024) i8* @aligned_alloc(i64 [[ALIGN:%.*]], i64 1024) +; CHECK-NEXT: [[CALL_1:%.*]] = tail call noalias i8* @aligned_alloc(i64 0, i64 1024) +; CHECK-NEXT: [[CALL_2:%.*]] = tail call noalias i8* @aligned_alloc(i64 32, i64 [[SIZE:%.*]]) +; CHECK-NEXT: [[TMP1:%.*]] = call i8* @foo(i8* [[CALL]], i8* [[CALL_1]], i8* [[CALL_2]]) +; CHECK-NEXT: ret i8* [[CALL]] ; %call = tail call noalias i8* @aligned_alloc(i64 %align, i64 1024) %call_1 = tail call noalias i8* @aligned_alloc(i64 0, i64 1024) -- 2.7.4