[llvm-commits] [llvm] r104088 - /llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp

[Dan Gohman]

Author: djg
Date: Tue May 18 18:48:08 2010
New Revision: 104088

URL: http://llvm.org/viewvc/llvm-project?rev=104088&view=rev
Log:
Fix the predicate which checks for non-sensical formulae which have
constants in registers which partially cancel out their immediate fields.

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=104088&r1=104087&r2=104088&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Tue May 18 18:48:08 2010
@@ -2572,10 +2572,11 @@
                J = NewF.BaseRegs.begin(), JE = NewF.BaseRegs.end();
                J != JE; ++J)
             if (const SCEVConstant *C = dyn_cast<SCEVConstant>(*J))
-              if (C->getValue()->getValue().isNegative() !=
-                    (NewF.AM.BaseOffs < 0) &&
-                  C->getValue()->getValue().abs()
-                    .ule(abs64(NewF.AM.BaseOffs)))
+              if ((C->getValue()->getValue() + NewF.AM.BaseOffs).abs().slt(
+                   abs64(NewF.AM.BaseOffs)) &&
+                  (C->getValue()->getValue() +
+                   NewF.AM.BaseOffs).countTrailingZeros() >=
+                   CountTrailingZeros_64(NewF.AM.BaseOffs))
                 goto skip_formula;
 
           // Ok, looks good.