[SelectionDAG] Propagate Disjoint flag. (llvm#88370)

Signed-off-by: feng.feng <feng.feng@iluvatar.com>
aniplcc · Apr 15, 2024 · 8ab50dd · 8ab50dd
1 parent 26d394f
commit 8ab50dd
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Showing 3 changed files with 19 additions and 2 deletions.
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9530,7 +9530,8 @@ static SDValue combineShiftOfShiftedLogic(SDNode *Shift, SelectionDAG &DAG) {
   SDValue ShiftSumC = DAG.getConstant(*C0Val + C1Val, DL, ShiftAmtVT);
   SDValue NewShift1 = DAG.getNode(ShiftOpcode, DL, VT, X, ShiftSumC);
   SDValue NewShift2 = DAG.getNode(ShiftOpcode, DL, VT, Y, C1);
-  return DAG.getNode(LogicOpcode, DL, VT, NewShift1, NewShift2);
+  return DAG.getNode(LogicOpcode, DL, VT, NewShift1, NewShift2,
+                     LogicOp->getFlags());
 }
 
 /// Handle transforms common to the three shifts, when the shift amount is a

diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -544,7 +544,8 @@ bool TargetLowering::ShrinkDemandedConstant(SDValue Op,
     if (!C.isSubsetOf(DemandedBits)) {
       EVT VT = Op.getValueType();
       SDValue NewC = TLO.DAG.getConstant(DemandedBits & C, DL, VT);
-      SDValue NewOp = TLO.DAG.getNode(Opcode, DL, VT, Op.getOperand(0), NewC);
+      SDValue NewOp = TLO.DAG.getNode(Opcode, DL, VT, Op.getOperand(0), NewC,
+                                      Op->getFlags());
       return TLO.CombineTo(Op, NewOp);
     }
 

diff --git a/llvm/test/CodeGen/X86/propagate-disjoint-in-shl-or.ll b/llvm/test/CodeGen/X86/propagate-disjoint-in-shl-or.ll
@@ -0,0 +1,15 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=x86_64 %s -start-before=x86-isel -o - | FileCheck %s
+
+define i32 @add_shl_or_disjoint(i32 %x) {
+; CHECK-LABEL: add_shl_or_disjoint:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    leal 165036822(,%rdi,4), %eax
+; CHECK-NEXT:    retq
+  %or = or disjoint i32 %x, 4027584529
+  %shl = shl i32 %or, 2
+  %add = add i32 %shl, 1234567890
+  ret i32 %add
+}
+