diff options
| -rw-r--r-- | llvm/lib/Analysis/MemorySSA.cpp | 8 | ||||
| -rw-r--r-- | llvm/test/Analysis/MemorySSA/loop-rotate-disablebasicaa.ll | 26 |
2 files changed, 33 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/MemorySSA.cpp b/llvm/lib/Analysis/MemorySSA.cpp index db12fcee3ef..cc3bca1c231 100644 --- a/llvm/lib/Analysis/MemorySSA.cpp +++ b/llvm/lib/Analysis/MemorySSA.cpp @@ -1736,9 +1736,15 @@ MemoryUseOrDef *MemorySSA::createNewAccess(Instruction *I, // FIXME: Replace this special casing with a more accurate modelling of // assume's control dependency. if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) - if (II->getIntrinsicID() == Intrinsic::assume || isa<DbgInfoIntrinsic>(II)) + if (II->getIntrinsicID() == Intrinsic::assume) return nullptr; + // Using a nonstandard AA pipelines might leave us with unexpected modref + // results for I, so add a check to not model instructions that may not read + // from or write to memory. This is necessary for correctness. + if (!I->mayReadFromMemory() && !I->mayWriteToMemory()) + return nullptr; + bool Def, Use; if (Template) { Def = dyn_cast_or_null<MemoryDef>(Template) != nullptr; diff --git a/llvm/test/Analysis/MemorySSA/loop-rotate-disablebasicaa.ll b/llvm/test/Analysis/MemorySSA/loop-rotate-disablebasicaa.ll new file mode 100644 index 00000000000..f601d48f4b9 --- /dev/null +++ b/llvm/test/Analysis/MemorySSA/loop-rotate-disablebasicaa.ll @@ -0,0 +1,26 @@ +; RUN: opt -disable-basicaa -print-memoryssa -disable-output %s 2>&1 | FileCheck %s + +; Note: if @foo is modelled as a MemoryDef, this test will assert with -loop-rotate, due to MemorySSA not +; being preserved when moving instructions that may not read from or write to memory. + +; CHECK-LABEL: @main +; CHECK-NOT: MemoryDef +define void @main() { +entry: + br label %for.cond120 + +for.cond120: ; preds = %for.body127, %entry + call void @foo() + br i1 undef, label %for.body127, label %for.cond.cleanup126 + +for.cond.cleanup126: ; preds = %for.cond120 + unreachable + +for.body127: ; preds = %for.cond120 + %0 = load i16**, i16*** undef, align 1 + br label %for.cond120 +} + +declare void @foo() readnone + + |
