diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp | 7 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstSimplify/insertelement.ll | 23 |
2 files changed, 29 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp b/llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp index 920b12b8a6a..e3edfe51458 100644 --- a/llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp +++ b/llvm/lib/Transforms/Scalar/InstSimplifyPass.cpp @@ -34,6 +34,11 @@ static bool runImpl(Function &F, const SimplifyQuery &SQ, do { for (BasicBlock &BB : F) { + // Unreachable code can take on strange forms that we are not prepared to + // handle. For example, an instruction may have itself as an operand. + if (!SQ.DT->isReachableFromEntry(&BB)) + continue; + SmallVector<Instruction *, 8> DeadInstsInBB; for (Instruction &I : BB) { // The first time through the loop, ToSimplify is empty and we try to @@ -87,7 +92,7 @@ struct InstSimplifyLegacyPass : public FunctionPass { AU.addRequired<OptimizationRemarkEmitterWrapperPass>(); } - /// runOnFunction - Remove instructions that simplify. + /// Remove instructions that simplify. bool runOnFunction(Function &F) override { if (skipFunction(F)) return false; diff --git a/llvm/test/Transforms/InstSimplify/insertelement.ll b/llvm/test/Transforms/InstSimplify/insertelement.ll index e487eeb96b0..97f656a7c82 100644 --- a/llvm/test/Transforms/InstSimplify/insertelement.ll +++ b/llvm/test/Transforms/InstSimplify/insertelement.ll @@ -67,3 +67,26 @@ define <8 x i8> @extract_insert_same_vec_and_index2(<8 x i8> %in, i32 %index) { %vec = insertelement <8 x i8> %in, i8 %val, i32 %index ret <8 x i8> %vec } + +; The insert is in an unreachable block, so it is allowed to point to itself. +; This would crash via stack overflow. + +define void @PR43218() { +; CHECK-LABEL: @PR43218( +; CHECK-NEXT: end: +; CHECK-NEXT: ret void +; CHECK: unreachable_infloop: +; CHECK-NEXT: [[EXTRACT:%.*]] = extractelement <2 x i64> [[BOGUS:%.*]], i32 0 +; CHECK-NEXT: [[T0:%.*]] = inttoptr i64 [[EXTRACT]] to i16**** +; CHECK-NEXT: [[BOGUS]] = insertelement <2 x i64> [[BOGUS]], i64 undef, i32 1 +; CHECK-NEXT: br label [[UNREACHABLE_INFLOOP:%.*]] +; +end: + ret void + +unreachable_infloop: + %extract = extractelement <2 x i64> %bogus, i32 0 + %t0 = inttoptr i64 %extract to i16**** + %bogus = insertelement <2 x i64> %bogus, i64 undef, i32 1 + br label %unreachable_infloop +} |
