================
@@ -12112,18 +12138,36 @@ void
SelectionDAGBuilder::lowerWorkItem(SwitchWorkListItem W, Value *Cond,
const APInt &SmallValue = Small.Low->getValue();
const APInt &BigValue = Big.Low->getValue();
+ // Incoming IR is switch table.Identify SRL/IPM/CC sequence for SystemZ
+ // and we want to avoid splitting condition code sequence across basic
+ // block for cases like (CC == 0) || (CC == 2) || (CC == 3), or
+ // (CC == 0) || (CC == 1) ^ (CC == 3), there could potentially be
+ // more cases like this.
+ const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+ bool IsSrlIPM = false;
+ if (NodeMap.count(Cond) && NodeMap[Cond].getNode())
+ IsSrlIPM = TLI.canLowerSRL_IPM_Switch(getValue(Cond));
// Check that there is only one bit different.
APInt CommonBit = BigValue ^ SmallValue;
- if (CommonBit.isPowerOf2()) {
+ if (CommonBit.isPowerOf2() || IsSrlIPM) {
SDValue CondLHS = getValue(Cond);
EVT VT = CondLHS.getValueType();
SDLoc DL = getCurSDLoc();
-
- SDValue Or = DAG.getNode(ISD::OR, DL, VT, CondLHS,
- DAG.getConstant(CommonBit, DL, VT));
- SDValue Cond = DAG.getSetCC(
- DL, MVT::i1, Or, DAG.getConstant(BigValue | SmallValue, DL, VT),
- ISD::SETEQ);
+ SDValue Cond;
+
+ if (CommonBit.isPowerOf2()) {
+ SDValue Or = DAG.getNode(ISD::OR, DL, VT, CondLHS,
+ DAG.getConstant(CommonBit, DL, VT));
+ Cond = DAG.getSetCC(DL, MVT::i1, Or,
+ DAG.getConstant(BigValue | SmallValue, DL, VT),
+ ISD::SETEQ);
+ } else if (IsSrlIPM && BigValue == 3 && SmallValue == 0) {
+ SDValue SetCC =
+ DAG.getSetCC(DL, MVT::i32, CondLHS,
+ DAG.getConstant(SmallValue, DL, VT), ISD::SETEQ);
+ Cond = DAG.getSetCC(DL, MVT::i32, SetCC,
+ DAG.getConstant(BigValue, DL, VT), ISD::SETEQ);
+ }
----------------
uweigand wrote:
Again, this very SystemZ specific optimization shouldn't really be here.
Doesn't this just revert the decision to introduce a switch statement that was
made above? Could this not handled either by the `visitBr` above via the
`getJumpConditionMergingParams` callback; or else fully in SystemZ DAGCombine
code?
https://github.com/llvm/llvm-project/pull/125970
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