It's possible that an all-zero GEP may be used as the argument to lifetime

intrinsics. In fact, we'll optimize a bitcast to that when possible. Detect it
when looking for the lifetime intrinsics.

No test case, noticed by inspection.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132906 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index 8416170d903264c2ece235c02c5434394ca15145..3eeedab925007139aeb4620a7252a2955ceb7a64 100644 (file)
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -734,11 +734,15 @@ static bool hasLifetimeMarkers(AllocaInst *AI) {
   if (AI->getType() == Int8PtrTy)
     return isUsedByLifetimeMarker(AI);
 
-  // Do a scan to find all the bitcasts to i8*.
+  // Do a scan to find all the bitcasts or GEPs to i8*.
   for (Value::use_iterator I = AI->use_begin(), E = AI->use_end(); I != E;
        ++I) {
     if (I->getType() != Int8PtrTy) continue;
-    if (!isa<BitCastInst>(*I)) continue;
+    if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*I)) {
+      if (!GEPI->hasAllZeroIndices()) continue;
+    } else if (!isa<BitCastInst>(*I)) {
+      continue;
+    }
     if (isUsedByLifetimeMarker(*I))
       return true;
   }