[RS4GC] Use an value handle to help isolate errors quickly

Inspired by the bug reported in 25846.  Whatever we end up doing about that one, the value handle change is a generally good one since it will help catch this type of mistake more quickly.

Patch by: Manuel Jacob

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255984 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp b/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
index ffa77bb2fd65af79df78f3014ca5c33decb17b2f..d72133287f5656a2d7250118760c692915e78590 100644 (file)
--- a/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ b/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -641,7 +641,7 @@ public:
 
 private:
   Status status;
-  Value *base; // non null only if status == base
+  AssertingVH<Value> base; // non null only if status == base
 };
 }
 
@@ -1098,10 +1098,10 @@ static Value *findBasePointer(Value *I, DefiningValueMapTy &cache) {
     NewInsts.erase(BaseI);
     ReverseMap.erase(BaseI);
     BaseI->replaceAllUsesWith(Replacement);
-    BaseI->eraseFromParent();
     assert(States.count(BDV));
     assert(States[BDV].isConflict() && States[BDV].getBase() == BaseI);
     States[BDV] = BDVState(BDVState::Conflict, Replacement);
+    BaseI->eraseFromParent();
   };
   const DataLayout &DL = cast<Instruction>(def)->getModule()->getDataLayout();
   while (!Worklist.empty()) {