================
@@ -8701,95 +8734,341 @@ SDValue SystemZTargetLowering::combineSETCC(
return SDValue();
}
-static bool combineCCMask(SDValue &CCReg, int &CCValid, int &CCMask) {
+static std::pair<SDValue, int> findCCUse(const SDValue &Val) {
+ auto *N = Val.getNode();
+ if (!N)
+ return std::make_pair(SDValue(), SystemZ::CCMASK_NONE);
+ switch (N->getOpcode()) {
+ default:
+ return std::make_pair(SDValue(), SystemZ::CCMASK_NONE);
+ case SystemZISD::IPM:
+ if (N->getOperand(0).getOpcode() == SystemZISD::CLC ||
+ N->getOperand(0).getOpcode() == SystemZ::CLST ||
+ N->getOperand(0).getOpcode() == SystemZISD::STRCMP)
+ return std::make_pair(N->getOperand(0), SystemZ::CCMASK_ICMP);
+ return std::make_pair(N->getOperand(0), SystemZ::CCMASK_ANY);
+ case ISD::SHL:
+ case ISD::SRA:
+ case ISD::SRL:
+ return findCCUse(N->getOperand(0));
+ case SystemZISD::SELECT_CCMASK: {
+ SDValue Op4CCReg = N->getOperand(4);
+ auto *Op4CCNode = Op4CCReg.getNode();
+ auto *CCValid = dyn_cast<ConstantSDNode>(N->getOperand(2));
+ if (!CCValid || !Op4CCNode)
+ return std::make_pair(SDValue(), SystemZ::CCMASK_NONE);
+ int CCValidVal = CCValid->getZExtValue();
+ if (Op4CCNode->getOpcode() == SystemZISD::ICMP ||
+ Op4CCNode->getOpcode() == SystemZISD::TM) {
+ auto [OpCC, OpCCValid] = findCCUse(Op4CCNode->getOperand(0));
+ if (OpCC != SDValue())
+ return std::make_pair(OpCC, OpCCValid);
+ }
+ auto [OpCC, OpCCValid] = findCCUse(Op4CCReg);
----------------
uweigand wrote:
You should *not* recurse directly into `Op4CCReg` here, as it is a CC link, not
a GPR link. If the CC link points neither to `ICMP` nor `TM`, we can only use
it directly as output.
https://github.com/llvm/llvm-project/pull/125970
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