[BasicAA] Fix handling of invariant group launders
Summary:
A recent patch ([[ https://reviews.llvm.org/rL331587 | rL331587 ]]) to Capture Tracking taught it that the `launder_invariant_group` intrinsic captures its argument only by returning it. Unfortunately, BasicAA still considered every call instruction as a possible escape source and hence concluded that the result of a `launder_invariant_group` call cannot alias any local non-escaping value. This led to [[ https://bugs.llvm.org/show_bug.cgi?id=37458 | bug 37458 ]].
This patch updates the relevant check for escape sources in BasicAA.
Reviewers: Prazek, kuhar, rsmith, hfinkel, sanjoy, xbolva00
Reviewed By: hfinkel, xbolva00
Subscribers: JDevlieghere, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D46900
llvm-svn: 332466
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index aaa79bc..55a53f2 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -132,7 +132,18 @@
/// Returns true if the pointer is one which would have been considered an
/// escape by isNonEscapingLocalObject.
static bool isEscapeSource(const Value *V) {
- if (isa<CallInst>(V) || isa<InvokeInst>(V) || isa<Argument>(V))
+ if (auto CS = ImmutableCallSite(V)) {
+ // launder_invariant_group captures its argument only by returning it,
+ // so it might not be considered an escape by isNonEscapingLocalObject.
+ // Note that adding similar special cases for intrinsics in CaptureTracking
+ // requires handling them here too.
+ if (CS.getIntrinsicID() == Intrinsic::launder_invariant_group)
+ return false;
+
+ return true;
+ }
+
+ if (isa<Argument>(V))
return true;
// The load case works because isNonEscapingLocalObject considers all