[llvm-commits] [llvm] r61402 - /llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp

[Dale Johannesen]

Author: johannes
Date: Tue Dec 23 17:05:26 2008
New Revision: 61402

URL: http://llvm.org/viewvc/llvm-project?rev=61402&view=rev
Log:
This fixes the bug in 175.vpr.  It doesn't fix the
other SPEC breakage.  I'll be reverting all recent
changes shortly, this checking is mostly so this
change doesn't get lost.


Modified:
    llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=61402&r1=61401&r2=61402&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Tue Dec 23 17:05:26 2008
@@ -1627,10 +1627,17 @@
         // The common base is emitted in the loop preheader. But since we
         // are reusing an IV, it has not been used to initialize the PHI node.
         // Add it to the expression used to rewrite the uses.
+        // When this use is outside the loop, we earlier subtracted the
+        // common base, and are adding it back here.  Use the same expression
+        // as before, rather than CommonBaseV, so DAGCombiner will zap it.
         if (!isa<ConstantInt>(CommonBaseV) ||
-            !cast<ConstantInt>(CommonBaseV)->isZero())
-          RewriteExpr = SE->getAddExpr(RewriteExpr,
+            !cast<ConstantInt>(CommonBaseV)->isZero()) {
+          if (L->contains(User.Inst->getParent()))
+            RewriteExpr = SE->getAddExpr(RewriteExpr,
                                        SE->getUnknown(CommonBaseV));
+          else
+            RewriteExpr = SE->getAddExpr(RewriteExpr, CommonExprs);
+        }
       }
 
       // Now that we know what we need to do, insert code before User for the