maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Fix a couple bugs in the const div stuff where we'd generate MULHS/MULHU 

for types that aren't legal, and fail a divisor is less than zero
comparison, which would cause us to drop a subtract.

llvm-svn: 23846
This commit is contained in:
Nate Begeman 2005-10-20 17:45:03 +00:00
parent a6efeb01f9
commit 7efe53d90b
1 changed files with 4 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -790,7 +790,8 @@ SDOperand DAGCombiner::visitSDIV(SDNode *N) {
// detect that too. // detect that too.
if (N1C && !isPowerOf2_64(N1C->getSignExtended()) && if (N1C && !isPowerOf2_64(N1C->getSignExtended()) &&
(N1C->getSignExtended() < -1 || N1C->getSignExtended() > 1) && (N1C->getSignExtended() < -1 || N1C->getSignExtended() > 1) &&
TLI.isOperationLegal(ISD::MULHS, VT) && TLI.isIntDivExpensive()) { TLI.isOperationLegal(ISD::MULHS, VT) && TLI.isTypeLegal(VT) &&
TLI.isIntDivExpensive()) {
return BuildSDIV(N); return BuildSDIV(N);
} }
return SDOperand(); return SDOperand();
@ -814,7 +815,7 @@ SDOperand DAGCombiner::visitUDIV(SDNode *N) {
TLI.getShiftAmountTy())); TLI.getShiftAmountTy()));
// fold (udiv x, c) -> alternate // fold (udiv x, c) -> alternate
if (N1C && N1C->getValue() && TLI.isOperationLegal(ISD::MULHU, VT) && if (N1C && N1C->getValue() && TLI.isOperationLegal(ISD::MULHU, VT) &&
TLI.isIntDivExpensive()) TLI.isTypeLegal(VT) && TLI.isIntDivExpensive())
return BuildUDIV(N); return BuildUDIV(N);
return SDOperand(); return SDOperand();
} }
@ -2555,7 +2556,7 @@ SDOperand DAGCombiner::BuildSDIV(SDNode *N) {
assert((VT == MVT::i32 || VT == MVT::i64) && assert((VT == MVT::i32 || VT == MVT::i64) &&
"BuildSDIV only operates on i32 or i64!"); "BuildSDIV only operates on i32 or i64!");
int64_t d = cast<ConstantSDNode>(N->getOperand(1))->getValue(); int64_t d = cast<ConstantSDNode>(N->getOperand(1))->getSignExtended();
ms magics = (VT == MVT::i32) ? magic32(d) : magic64(d); ms magics = (VT == MVT::i32) ? magic32(d) : magic64(d);
// Multiply the numerator (operand 0) by the magic value // Multiply the numerator (operand 0) by the magic value