[AA] Handle callbr instructions in alias analysis

Before this change, AAResults::getModRefInfo() was missing a case for
callbr instructions (asm goto), which may read/write memory. In PR52735,
this led to a miscompile where a load was incorrect eliminated.

Add this missing case, as well as an assert verifying that all
memory-accessing instructions are handled properly.

Fixes #52735.

Differential Revision: https://reviews.llvm.org/D115992

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index af63692..4919906 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -696,14 +696,16 @@ ModRefInfo AAResults::getModRefInfo(const Instruction *I,
   case Instruction::AtomicRMW:
     return getModRefInfo((const AtomicRMWInst *)I, Loc, AAQIP);
   case Instruction::Call:
-    return getModRefInfo((const CallInst *)I, Loc, AAQIP);
+  case Instruction::CallBr:
   case Instruction::Invoke:
-    return getModRefInfo((const InvokeInst *)I, Loc, AAQIP);
+    return getModRefInfo((const CallBase *)I, Loc, AAQIP);
   case Instruction::CatchPad:
     return getModRefInfo((const CatchPadInst *)I, Loc, AAQIP);
   case Instruction::CatchRet:
     return getModRefInfo((const CatchReturnInst *)I, Loc, AAQIP);
   default:
+    assert(!I->mayReadOrWriteMemory() &&
+           "Unhandled memory access instruction!");
     return ModRefInfo::NoModRef;
   }
 }