From ead28bd04bf42cdf8c29d12fa4c0f9d29a4c58cd Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Wed, 27 May 2009 20:00:18 +0000
Subject: In ChangeCompareStride, when the stride to be reused is truncated to
 a smaller type, promoted its offset back up to the type of the new
 comparison. This fixes PR4222.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72493 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/LoopStrengthReduce.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

(limited to 'lib/Transforms/Scalar/LoopStrengthReduce.cpp')

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index adfa5272a9..834a95d731 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2005,11 +2005,16 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
         ConstantInt *CI = ConstantInt::get(NewCmpIntTy, NewCmpVal);
         NewCmpRHS = ConstantExpr::getIntToPtr(CI, NewCmpTy);
       }
+      NewOffset = CondUse->getOffset();
+      if (CondUse->isSigned())
+        NewOffset = SE->getNoopOrSignExtend(CondUse->getOffset(), NewCmpTy);
+      else
+        NewOffset = SE->getNoopOrZeroExtend(CondUse->getOffset(), NewCmpTy);
       NewOffset = TyBits == NewTyBits
-        ? SE->getMulExpr(CondUse->getOffset(),
+        ? SE->getMulExpr(NewOffset,
                          SE->getConstant(ConstantInt::get(CmpTy, Scale)))
         : SE->getConstant(ConstantInt::get(NewCmpIntTy,
-          cast<SCEVConstant>(CondUse->getOffset())->getValue()
+          cast<SCEVConstant>(NewOffset)->getValue()
             ->getSExtValue()*Scale));
       break;
     }
-- 
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