commit e19c840d6c6fe075b61a21a0f6abe338afba666d
author David Greene <greened@obbligato.org> Wed May 06 17:39:26 2009 +0000
committer David Greene <greened@obbligato.org> Wed May 06 17:39:26 2009 +0000
tree 77b1c8567c919909c4a5d556ab350c1f088c5628
parent e9d87f49063cb1bd213d8e9c339b9b63393cc2d9

Make sure to use signed arithmetic in APInt to fix a regression.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71090 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/LoopStrengthReduce.cpp

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index e2cbbc2..9e6f2b0 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2027,9 +2027,10 @@
 
       Scale = SSInt / CmpSSInt;
       int64_t NewCmpVal = CmpVal * Scale;
-      APInt Mul = APInt(BitWidth, NewCmpVal);
+      APInt Mul = APInt(BitWidth*2, CmpVal, true);
+      Mul = Mul * APInt(BitWidth*2, Scale, true);
       // Check for overflow.
-      if (Mul.getSExtValue() != NewCmpVal)
+      if (!Mul.isSignedIntN(BitWidth)) {
         continue;
 
       // Watch out for overflow.