update memdep when an instruction is deleted. This code isn't

actually reached in the testcase in PR8954, but it's safe and good
practice.

llvm-svn: 123224

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index a4bd7c1eb42..db6ed3977d1 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -1383,8 +1383,11 @@ bool GVN::processNonLocalLoad(LoadInst *LI,
   }
 
   if (!CanDoPRE) {
-    while (!NewInsts.empty())
-      NewInsts.pop_back_val()->eraseFromParent();
+    while (!NewInsts.empty()) {
+      Instruction *I = NewInsts.pop_back_val();
+      if (MD) MD->removeInstruction(I);
+      I->eraseFromParent();
+    }
     return false;
   }