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[X86] Remove unneeded code that looks for (and (i8 (X86setcc_c)) 

I don't believe we use this construct anymore so I don't think
we need to look for it.
This commit is contained in:
Craig Topper 2020-02-03 23:17:20 -08:00
parent e53bbf1213
commit cd14b4a62b
2 changed files with 0 additions and 25 deletions
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18
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -43869,28 +43869,10 @@ static SDValue combineFMADDSUB(SDNode *N, SelectionDAG &DAG,
static SDValue combineZext(SDNode *N, SelectionDAG &DAG,
TargetLowering::DAGCombinerInfo &DCI,
const X86Subtarget &Subtarget) {
// (i32 zext (and (i8 x86isd::setcc_carry), 1)) ->
// (and (i32 x86isd::setcc_carry), 1)
// This eliminates the zext. This transformation is necessary because
// ISD::SETCC is always legalized to i8.
SDLoc dl(N);
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
if (N0.getOpcode() == ISD::AND &&
N0.hasOneUse() &&
N0.getOperand(0).hasOneUse()) {
SDValue N00 = N0.getOperand(0);
if (N00.getOpcode() == X86ISD::SETCC_CARRY) {
if (!isOneConstant(N0.getOperand(1)))
return SDValue();
return DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(X86ISD::SETCC_CARRY, dl, VT,
N00.getOperand(0), N00.getOperand(1)),
DAG.getConstant(1, dl, VT));
}
}
if (SDValue NewCMov = combineToExtendCMOV(N, DAG))
return NewCMov;

7
llvm/lib/Target/X86/X86InstrCompiler.td
View File

@ -349,13 +349,6 @@ def : Pat<(i32 (sext (i8 (X86setcc_c X86_COND_B, EFLAGS)))),
def : Pat<(i64 (sext (i8 (X86setcc_c X86_COND_B, EFLAGS)))),
(SETB_C64r)>;
// We canonicalize 'setb' to "(and (sbb reg,reg), 1)" on the hope that the and
// will be eliminated and that the sbb can be extended up to a wider type. When
// this happens, it is great. However, if we are left with an 8-bit sbb and an
// and, we might as well just match it as a setb.
def : Pat<(and (i8 (X86setcc_c X86_COND_B, EFLAGS)), 1),
(SETCCr (i8 2))>;
// Patterns to give priority when both inputs are zero so that we don't use
// an immediate for the RHS.
// TODO: Should we use a 32-bit sbb for 8/16 to push the extract_subreg out?