From e99f98262c5c766ec832b756aa303a3cdcc01bd7 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 27 Apr 2009 20:35:32 +0000
Subject: Permit ChangeCompareStride to rewrite a comparison when the factor
 between the comparison's iv stride and the candidate stride is exactly -1.

llvm-svn: 70244
---
 llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'llvm/lib/Transforms')

diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index c436cec26ed..a6795a72ef9 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2028,7 +2028,9 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
       if (!isa<SCEVConstant>(SI->first))
         continue;
       int64_t SSInt = cast<SCEVConstant>(SI->first)->getValue()->getSExtValue();
-      if (abs(SSInt) <= abs(CmpSSInt) || (SSInt % CmpSSInt) != 0)
+      if (SSInt == CmpSSInt ||
+          abs(SSInt) < abs(CmpSSInt) ||
+          (SSInt % CmpSSInt) != 0)
         continue;
 
       Scale = SSInt / CmpSSInt;
-- 
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