================
@@ -8030,7 +8077,431 @@ SDValue SystemZTargetLowering::combineBSWAP(
return SDValue();
}
+// Combine IPM sequence for flag output operands.
+static bool combineSRL_IPM_CCMask(SDValue &CCReg, int &CCValid, int &CCMask) {
+ // Convert CCVal to CCMask and update it along with CCValid.
+ const auto convertCCValToCCMask = [&CCMask, &CCValid](int CCVal) {
+ bool Invert = false;
+ if (CCMask == SystemZ::CCMASK_CMP_NE)
+ Invert = !Invert;
+ if (CCMask == SystemZ::CCMASK_CMP_EQ || CCMask == SystemZ::CCMASK_CMP_NE) {
+ CCMask = CCMaskForSystemZCCVal(CCVal);
+ if (Invert)
+ CCMask ^= SystemZ::CCMASK_ANY;
+ CCValid = SystemZ::CCMASK_ANY;
+ return true;
+ } else if (CCMask == SystemZ::CCMASK_CMP_LT) {
+ // CC in range [0, CCVal).
+ CCMask = ((~0U << (4 - CCVal)) & SystemZ::CCMASK_ANY);
+ CCValid = SystemZ::CCMASK_ANY;
+ return true;
+ } else if (CCMask == SystemZ::CCMASK_CMP_GT) {
+ // CC in range (CCVal, 3].
+ CCMask = (~(~0U << (3 - CCVal))) & SystemZ::CCMASK_ANY;
+ CCValid = SystemZ::CCMASK_ANY;
+ return true;
+ }
+ return false;
+ };
+ // Check (SRL (IPM (CC))) and update CCReg to combine.
+ const auto isSRL_IPM_CCSequence = [&CCReg](SDNode *N) {
+ if (!N || N->getOpcode() != ISD::SRL)
+ return false;
+ auto *SRLCount = dyn_cast<ConstantSDNode>(N->getOperand(1));
+ if (!SRLCount || SRLCount->getZExtValue() != SystemZ::IPM_CC)
+ return false;
+ auto *IPM = N->getOperand(0).getNode();
+ if (!IPM || IPM->getOpcode() != SystemZISD::IPM)
+ return false;
+ auto *IPMOp0 = IPM->getOperand(0).getNode();
+ if (!IPMOp0 || IPMOp0->getNumOperands() < 2)
+ return false;
+ auto *RN = dyn_cast<RegisterSDNode>(IPMOp0->getOperand(1));
+ // Check if operand 1 is SystemZ::CC. Also, it avoids srl/ipm/tbegin and
+ // srl/ipm/tend kind of sequences.
----------------
uweigand wrote:
Why is this check needed? The logic should be correct no matter the operand
of `IPM`. In fact, we might *want* to optimize these sequences for `tbegin` or
`tend` (or, more importantly, some of the vector intrinsics).
https://github.com/llvm/llvm-project/pull/125970
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