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improve the setcc -> setcc_carry optimization to happen more

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consistently by moving it out of lowering into dag combine.

Add some missing patterns for matching away extended versions of setcc_c.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122201 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2010-12-19 22:08:31 +00:00
parent 22d67cf6ac
commit c19d1c3ba2
6 changed files with 68 additions and 35 deletions
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lib/Target/X86/X86ISelLowering.cpp
+22 -11
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@@ -7053,17 +7053,9 @@ SDValue X86TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) const {
if (X86CC == X86::COND_INVALID)
return SDValue();
SDValue Cond = EmitCmp(Op0, Op1, X86CC, DAG);
// Use sbb x, x to materialize carry bit into a GPR.
if (X86CC == X86::COND_B)
return DAG.getNode(ISD::AND, dl, MVT::i8,
DAG.getNode(X86ISD::SETCC_CARRY, dl, MVT::i8,
DAG.getConstant(X86CC, MVT::i8), Cond),
DAG.getConstant(1, MVT::i8));
SDValue EFLAGS = EmitCmp(Op0, Op1, X86CC, DAG);
return DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
DAG.getConstant(X86CC, MVT::i8), Cond);
DAG.getConstant(X86CC, MVT::i8), EFLAGS);
}
SDValue X86TargetLowering::LowerVSETCC(SDValue Op, SelectionDAG &DAG) const {
@@ -11430,13 +11422,31 @@ static SDValue PerformZExtCombine(SDNode *N, SelectionDAG &DAG) {
return SDValue();
}
// Optimize RES = X86ISD::SETCC CONDCODE, EFLAG_INPUT
static SDValue PerformSETCCCombine(SDNode *N, SelectionDAG &DAG) {
unsigned X86CC = N->getConstantOperandVal(0);
SDValue EFLAG = N->getOperand(1);
DebugLoc DL = N->getDebugLoc();
// Materialize "setb reg" as "sbb reg,reg", since it can be extended without
// a zext and produces an all-ones bit which is more useful than 0/1 in some
// cases.
if (X86CC == X86::COND_B)
return DAG.getNode(ISD::AND, DL, MVT::i8,
DAG.getNode(X86ISD::SETCC_CARRY, DL, MVT::i8,
DAG.getConstant(X86CC, MVT::i8), EFLAG),
DAG.getConstant(1, MVT::i8));
return SDValue();
}
SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
SelectionDAG &DAG = DCI.DAG;
switch (N->getOpcode()) {
default: break;
case ISD::EXTRACT_VECTOR_ELT:
return PerformEXTRACT_VECTOR_ELTCombine(N, DAG, *this);
return PerformEXTRACT_VECTOR_ELTCombine(N, DAG, *this);
case ISD::SELECT: return PerformSELECTCombine(N, DAG, Subtarget);
case X86ISD::CMOV: return PerformCMOVCombine(N, DAG, DCI);
case ISD::MUL: return PerformMulCombine(N, DAG, DCI);
@@ -11452,6 +11462,7 @@ SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
case X86ISD::BT: return PerformBTCombine(N, DAG, DCI);
case X86ISD::VZEXT_MOVL: return PerformVZEXT_MOVLCombine(N, DAG);
case ISD::ZERO_EXTEND: return PerformZExtCombine(N, DAG);
case X86ISD::SETCC: return PerformSETCCCombine(N, DAG);
case X86ISD::SHUFPS: // Handle all target specific shuffles
case X86ISD::SHUFPD:
case X86ISD::PALIGN: