[AliasAnalysis] CatchPad and CatchRet can modify escaped memory

CatchPad and CatchRet behave a lot like function calls: they can
potentially modify any memory which has been escaped.

llvm-svn: 253323

1 files changed, 26 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 0fef5c66651..35f2e97622f 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -247,6 +247,32 @@ ModRefInfo AAResults::getModRefInfo(const VAArgInst *V,
   return MRI_ModRef;
 }
 
+ModRefInfo AAResults::getModRefInfo(const CatchPadInst *CatchPad,
+                                    const MemoryLocation &Loc) {
+  if (Loc.Ptr) {
+    // If the pointer is a pointer to constant memory,
+    // then it could not have been modified by this catchpad.
+    if (pointsToConstantMemory(Loc))
+      return MRI_NoModRef;
+  }
+
+  // Otherwise, a catchpad reads and writes.
+  return MRI_ModRef;
+}
+
+ModRefInfo AAResults::getModRefInfo(const CatchReturnInst *CatchRet,
+                                    const MemoryLocation &Loc) {
+  if (Loc.Ptr) {
+    // If the pointer is a pointer to constant memory,
+    // then it could not have been modified by this catchpad.
+    if (pointsToConstantMemory(Loc))
+      return MRI_NoModRef;
+  }
+
+  // Otherwise, a catchret reads and writes.
+  return MRI_ModRef;
+}
+
 ModRefInfo AAResults::getModRefInfo(const AtomicCmpXchgInst *CX,
                                     const MemoryLocation &Loc) {
   // Acquire/Release cmpxchg has properties that matter for arbitrary addresses.