From: Dan Gohman <gohman@apple.com>
Date: Sun, 27 Sep 2009 15:30:00 +0000 (+0000)
Subject: Instead of testing whether an instruction dominates the loop preheader,
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=00cb67359fc2515eb972cd41fa35f8a0d2b22b87;p=oota-llvm.git

Instead of testing whether an instruction dominates the loop preheader,
test whether it properly dominates the loop header. This is equivalent
when the loop has a preheader, and has the advantage of working when
the loop doesn't have a preheader. Since IVUsers doesn't Require
LoopSimplify, the loop isn't guaranteed to have a preheader.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82899 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/IVUsers.cpp b/lib/Analysis/IVUsers.cpp
index ecb7df80cf1..543e017fc9d 100644
--- a/lib/Analysis/IVUsers.cpp
+++ b/lib/Analysis/IVUsers.cpp
@@ -121,11 +121,11 @@ static bool getSCEVStartAndStride(const SCEV *&SH, Loop *L, Loop *UseLoop,
 
   Start = SE->getAddExpr(Start, AddRecStart);
 
-  // If stride is an instruction, make sure it dominates the loop preheader.
+  // If stride is an instruction, make sure it properly dominates the header.
   // Otherwise we could end up with a use before def situation.
   if (!isa<SCEVConstant>(AddRecStride)) {
-    BasicBlock *Preheader = L->getLoopPreheader();
-    if (!AddRecStride->dominates(Preheader, DT))
+    BasicBlock *Header = L->getHeader();
+    if (!AddRecStride->properlyDominates(Header, DT))
       return false;
 
     DEBUG(errs() << "[" << L->getHeader()->getName()