diff options
Diffstat (limited to 'lib/Transforms/Scalar/Reassociate.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/Reassociate.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/Reassociate.cpp b/lib/Transforms/Scalar/Reassociate.cpp index 4a99f4a844..1decde13b8 100644 --- a/lib/Transforms/Scalar/Reassociate.cpp +++ b/lib/Transforms/Scalar/Reassociate.cpp @@ -933,6 +933,15 @@ void Reassociate::ReassociateBB(BasicBlock *BB) { isa<VectorType>(BI->getType())) continue; // Floating point ops are not associative. + // Do not reassociate boolean (i1) expressions. We want to preserve the + // original order of evaluation for short-circuited comparisons that + // SimplifyCFG has folded to AND/OR expressions. If the expression + // is not further optimized, it is likely to be transformed back to a + // short-circuited form for code gen, and the source order may have been + // optimized for the most likely conditions. + if (BI->getType()->isInteger(1)) + continue; + // If this is a subtract instruction which is not already in negate form, // see if we can convert it to X+-Y. if (BI->getOpcode() == Instruction::Sub) { |