BasicAA was making the assumption that a local allocation which hadn't escaped
couldn't ever be the return of call instruction. However, it's quite possible
that said local allocation is itself the return of a function call. That's
what malloc and calloc are for, actually.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64442 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 1b26dc4..ef91850 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -319,7 +319,7 @@
// If the pointer is to a locally allocated object that does not escape,
// then the call can not mod/ref the pointer unless the call takes the
// argument without capturing it.
- if (isNonEscapingLocalObject(Object)) {
+ if (isNonEscapingLocalObject(Object) && CS.getInstruction() != Object) {
bool passedAsArg = false;
// TODO: Eventually only check 'nocapture' arguments.
for (CallSite::arg_iterator CI = CS.arg_begin(), CE = CS.arg_end();
@@ -414,10 +414,10 @@
// non-escaping local object, then we know the object couldn't escape to a
// point where the call could return it.
if ((isa<CallInst>(O1) || isa<InvokeInst>(O1)) &&
- isNonEscapingLocalObject(O2))
+ isNonEscapingLocalObject(O2) && O1 != O2)
return NoAlias;
if ((isa<CallInst>(O2) || isa<InvokeInst>(O2)) &&
- isNonEscapingLocalObject(O1))
+ isNonEscapingLocalObject(O1) && O1 != O2)
return NoAlias;
// If we have two gep instructions with must-alias'ing base pointers, figure