diff --git a/llvm/include/llvm/Analysis/VectorUtils.h b/llvm/include/llvm/Analysis/VectorUtils.h --- a/llvm/include/llvm/Analysis/VectorUtils.h +++ b/llvm/include/llvm/Analysis/VectorUtils.h @@ -17,6 +17,7 @@ #include "llvm/Analysis/LoopAccessAnalysis.h" #include "llvm/Analysis/TargetLibraryInfo.h" #include "llvm/IR/IRBuilder.h" +#include "llvm/Support/CheckedArithmetic.h" namespace llvm { @@ -277,7 +278,11 @@ bool insertMember(InstTy *Instr, int32_t Index, uint32_t NewAlign) { assert(NewAlign && "The new member's alignment should be non-zero"); - int32_t Key = Index + SmallestKey; + // Make sure the key fits in an int32_t. + Optional MaybeKey = checkedAdd(Index, SmallestKey); + if (!MaybeKey) + return false; + int32_t Key = *MaybeKey; // Skip if there is already a member with the same index. if (Members.find(Key) != Members.end()) @@ -285,13 +290,19 @@ if (Key > LargestKey) { // The largest index is always less than the interleave factor. - if (Index >= static_cast(Factor)) + if (Index >= static_cast(Factor)) return false; LargestKey = Key; } else if (Key < SmallestKey) { + + // Make sure the largest index fits in an int32_t. + Optional MaybeLargestIndex = checkedSub(LargestKey, Key); + if (!MaybeLargestIndex) + return false; + // The largest index is always less than the interleave factor. - if (LargestKey - Key >= static_cast(Factor)) + if (*MaybeLargestIndex >= static_cast(Factor)) return false; SmallestKey = Key; diff --git a/llvm/include/llvm/Support/CheckedArithmetic.h b/llvm/include/llvm/Support/CheckedArithmetic.h --- a/llvm/include/llvm/Support/CheckedArithmetic.h +++ b/llvm/include/llvm/Support/CheckedArithmetic.h @@ -49,6 +49,15 @@ return checkedOp(LHS, RHS, &llvm::APInt::sadd_ov); } +/// Subtract two signed integers \p LHS and \p RHS. +/// \return Optional of sum if no signed overflow occurred, +/// \c None otherwise. +template +typename std::enable_if::value, llvm::Optional>::type +checkedSub(T LHS, T RHS) { + return checkedOp(LHS, RHS, &llvm::APInt::ssub_ov); +} + /// Multiply two signed integers \p LHS and \p RHS. /// \return Optional of product if no signed overflow occurred, /// \c None otherwise. diff --git a/llvm/test/Transforms/LoopVectorize/X86/interleaved-accesses-large-gap.ll b/llvm/test/Transforms/LoopVectorize/X86/interleaved-accesses-large-gap.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Transforms/LoopVectorize/X86/interleaved-accesses-large-gap.ll @@ -0,0 +1,40 @@ +; RUN: opt < %s -loop-vectorize -mtriple x86_64 -S | FileCheck %s + +%struct.ST4 = type { i32, i32, i32, i32 } + +; The gaps between the memory access in this function are too large for +; interleaving. + +; Test from https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=7560 +define void @test1(%struct.ST4* noalias %B) { +; CHECK-LABEL: @test1 +; CHECK-NEXT: entry: +; CHECK-NEXT: br label %for.body + +; CHECK-LABEL: for.body: +; CHECK: store i32 +; CHECK: store i32 +; CHECK: store i32 +; CHECK: store i32 +; CHECK-NOT: store +; +entry: + br label %for.body + +for.body: ; preds = %for.body, %entry + %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ] + %p1 = getelementptr inbounds %struct.ST4, %struct.ST4* %B, i64 %indvars.iv, i32 0 + store i32 65536, i32* %p1, align 4 + %p2 = getelementptr i32, i32* %p1, i32 -2147483648 + store i32 65536, i32* %p2, align 4 + %p3 = getelementptr inbounds %struct.ST4, %struct.ST4* %B, i64 %indvars.iv, i32 2 + store i32 10, i32* %p3, align 4 + %p4 = getelementptr inbounds %struct.ST4, %struct.ST4* %B, i64 %indvars.iv, i32 3 + store i32 12, i32* %p4, align 4 + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 + %exitcond = icmp eq i64 %indvars.iv.next, 1024 + br i1 %exitcond, label %for.cond.cleanup, label %for.body + +for.cond.cleanup: ; preds = %for.body + ret void +}