From 8c0d29fee988928d2ce439b7a5f772e1cda62060 Mon Sep 17 00:00:00 2001
From: Dan Gohman <dan433584@gmail.com>
Date: Tue, 12 Feb 2013 19:05:10 +0000
Subject: [PATCH] When disabling PRE for a value is directly redundant with
 itself (through a loop), don't continue to iterate through the reamining
 predecessors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174994 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/GVN.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 0fe10960cc7..ff55f6fc2f2 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -2455,7 +2455,9 @@ bool GVN::performPRE(Function &F) {
           PREPred = P;
           ++NumWithout;
         } else if (predV == CurInst) {
+          /* CurInst dominates this predecessor. */
           NumWithout = 2;
+          break;
         } else {
           predMap[P] = predV;
           ++NumWith;
-- 
2.34.1