diff options
| -rw-r--r-- | lib/Analysis/MemoryBuiltins.cpp | 12 | ||||
| -rw-r--r-- | test/Instrumentation/BoundsChecking/simple.ll | 17 |
2 files changed, 24 insertions, 5 deletions
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp index e710a998bf..8e89aa9848 100644 --- a/lib/Analysis/MemoryBuiltins.cpp +++ b/lib/Analysis/MemoryBuiltins.cpp @@ -634,13 +634,15 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) { if (Instruction *I = dyn_cast<Instruction>(V)) Builder.SetInsertPoint(I); - // record the pointers that were handled in this run, so that they can be - // cleaned later if something fails - SeenVals.insert(V); - // now compute the size and offset SizeOffsetEvalType Result; - if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) { + + // Record the pointers that were handled in this run, so that they can be + // cleaned later if something fails. We also use this set to break cycles that + // can occur in dead code. + if (!SeenVals.insert(V)) { + Result = unknown(); + } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) { Result = visitGEPOperator(*GEP); } else if (Instruction *I = dyn_cast<Instruction>(V)) { Result = visit(*I); diff --git a/test/Instrumentation/BoundsChecking/simple.ll b/test/Instrumentation/BoundsChecking/simple.ll index 16870c78a8..72b58f4b0a 100644 --- a/test/Instrumentation/BoundsChecking/simple.ll +++ b/test/Instrumentation/BoundsChecking/simple.ll @@ -126,3 +126,20 @@ define i64 @f12(i64 %x, i64 %y) nounwind { %4 = load i64* %3, align 8 ret i64 %4 } + +; PR17402 +; CHECK-LABEL: @f13 +define void @f13() nounwind { +entry: + br label %alive + +dead: + ; Self-refential GEPs can occur in dead code. + %incdec.ptr = getelementptr inbounds i32* %incdec.ptr, i64 1 + ; CHECK: %incdec.ptr = getelementptr inbounds i32* %incdec.ptr + %l = load i32* %incdec.ptr + br label %alive + +alive: + ret void +} |