[AssumptionCache] Avoid dangling llvm.assume calls in the cache

PR49043 exposed a problem when it comes to RAUW llvm.assumes. While
D96106 would fix it for GVNSink, it seems a more general concern. To
avoid future problems this patch moves away from the vector of weak
reference model used in the assumption cache. Instead, we track the
llvm.assume calls with a callback handle which will remove itself from
the cache if the call is deleted.

Fixes PR49043.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D96168

1 files changed, 5 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Utils/PredicateInfo.cpp b/llvm/lib/Transforms/Utils/PredicateInfo.cpp
index 3312a6f..af5a72a 100644
--- a/llvm/lib/Transforms/Utils/PredicateInfo.cpp
+++ b/llvm/lib/Transforms/Utils/PredicateInfo.cpp
@@ -532,10 +532,11 @@ void PredicateInfoBuilder::buildPredicateInfo() {
       processSwitch(SI, BranchBB, OpsToRename);
     }
   }
-  for (auto &Assume : AC.assumptions()) {
-    if (auto *II = dyn_cast_or_null<IntrinsicInst>(Assume))
-      if (DT.isReachableFromEntry(II->getParent()))
-        processAssume(II, II->getParent(), OpsToRename);
+  for (auto &AssumeVH : AC.assumptions()) {
+    CallInst *AssumeCI = AssumeVH.getAssumeCI();
+    if (DT.isReachableFromEntry(AssumeCI->getParent()))
+      processAssume(cast<IntrinsicInst>(AssumeCI), AssumeCI->getParent(),
+                    OpsToRename);
   }
   // Now rename all our operations.
   renameUses(OpsToRename);