diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Target/IA64/IA64ISelPattern.cpp | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/lib/Target/IA64/IA64ISelPattern.cpp b/lib/Target/IA64/IA64ISelPattern.cpp index 5ac5df5c93..badc89f814 100644 --- a/lib/Target/IA64/IA64ISelPattern.cpp +++ b/lib/Target/IA64/IA64ISelPattern.cpp @@ -784,7 +784,7 @@ SDOperand ISel::BuildConstmulSequence(SDOperand N) { bool flippedSign; unsigned preliminaryShift=0; - assert(constant > 0 && "erk, don't multiply by zero or negative nums\n"); + assert(constant != 0 && "erk, you're trying to multiply by constant zero\n"); // first, we make the constant to multiply by positive if(constant<0) { @@ -832,15 +832,24 @@ SDOperand ISel::BuildConstmulSequence(SDOperand N) { } // don't forget flippedSign and preliminaryShift! - SDOperand finalresult; + SDOperand shiftedresult; if(preliminaryShift) { SDOperand finalshift = ISelDAG->getConstant(preliminaryShift, MVT::i64); - finalresult = ISelDAG->getNode(ISD::SHL, MVT::i64, + shiftedresult = ISelDAG->getNode(ISD::SHL, MVT::i64, results[ops.size()-1], finalshift); } else { // there was no preliminary divide-by-power-of-2 required - finalresult = results[ops.size()-1]; + shiftedresult = results[ops.size()-1]; } + SDOperand finalresult; + if(flippedSign) { // if we were multiplying by a negative constant: + SDOperand zero = ISelDAG->getConstant(0, MVT::i64); + // subtract the result from 0 to flip its sign + finalresult = ISelDAG->getNode(ISD::SUB, MVT::i64, zero, shiftedresult); + } else { // there was no preliminary multiply by -1 required + finalresult = shiftedresult; + } + return finalresult; } |