Add code in MipsDAGToDAGISel for selecting constant +0.0.

MIPS64 can generate constant +0.0 with a single DMTC1 instruction. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146999 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Akira Hatanaka 2011-12-20 22:25:50 +00:00
parent 52346e964f
commit 990d639f55
2 changed files with 13 additions and 0 deletions

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@ -293,6 +293,12 @@ SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
case ISD::ConstantFP: {
ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(Node);
if (Node->getValueType(0) == MVT::f64 && CN->isExactlyValue(+0.0)) {
if (Subtarget.hasMips64()) {
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
Mips::ZERO_64, MVT::i64);
return CurDAG->getMachineNode(Mips::DMTC1, dl, MVT::f64, Zero);
}
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
Mips::ZERO, MVT::i32);
return CurDAG->getMachineNode(Mips::BuildPairF64, dl, MVT::f64, Zero,

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@ -0,0 +1,7 @@
; RUN: llc < %s -march=mips64el -mcpu=mips64 -mattr=n64 | FileCheck %s
define double @foo1() nounwind readnone {
entry:
; CHECK: dmtc1 $zero
ret double 0.000000e+00
}