diff options
Diffstat (limited to 'llvm/lib/Transforms/Scalar/InstructionCombining.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index cf4af791691..67a54018c37 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -694,8 +694,10 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) { return ReplaceInstUsesWith(I, RHS); // X + 0 --> X - if (!I.getType()->isFloatingPoint() && // -0 + +0 = +0, so it's not a noop - RHSC->isNullValue()) + // 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()) return ReplaceInstUsesWith(I, LHS); // X + (signbit) --> X ^ signbit |
