[llvm-commits] CVS: llvm/lib/Transforms/Scalar/InstructionCombining.cpp

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Scalar:

InstructionCombining.cpp updated: 1.59 -> 1.60

---
Log message:

Fold ashr -1, X into -1


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Diffs of the changes:

Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.59 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.60
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.59	Tue Oct  1 17:38:41 2002
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp	Tue Oct  8 11:16:40 2002
@@ -503,6 +503,12 @@
       return BinaryOperator::create(Instruction::Add, Op0, Op0, I.getName());
 
   }
+
+  // shr int -1, X = -1   (for any arithmetic shift rights of ~0)
+  if (ConstantSInt *CSI = dyn_cast<ConstantSInt>(Op0))
+    if (I.getOpcode() == Instruction::Shr && CSI->isAllOnesValue())
+      return ReplaceInstUsesWith(I, CSI);
+  
   return 0;
 }