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

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Scalar:

InstructionCombining.cpp updated: 1.386 -> 1.387
---
Log message:

Oops, X+0.0 isn't foldable, but X+-0.0 is.


---
Diffs of the changes:  (+5 -4)

 InstructionCombining.cpp |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)


Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.386 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.387
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.386	Mon Oct 17 12:49:32 2005
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp	Mon Oct 17 12:56:38 2005
@@ -694,11 +694,12 @@
       return ReplaceInstUsesWith(I, RHS);
 
     // X + 0 --> X
-    // NOTE: -0 + +0 = +0 in non-default rounding modes.  When we support them
-    // we must disable this.  Note that 0.0-0.0 = -0.0, so this doesn't hold
-    // for SUB.
-    if (RHSC->isNullValue())
+    if (!I.getType()->isFloatingPoint()) { // NOTE: -0 + +0 = +0.
+      if (RHSC->isNullValue())
+        return ReplaceInstUsesWith(I, LHS);
+    } else if (cast<ConstantFP>(RHSC)->isExactlyValue(-0.0)) {
       return ReplaceInstUsesWith(I, LHS);
+    }
 
     // X + (signbit) --> X ^ signbit
     if (ConstantInt *CI = dyn_cast<ConstantInt>(RHSC)) {