[PATCH] D100107: [AArch64][SVE] Optimize index_vector with add

[JunMa via Phabricator via llvm-commits]

junparser updated this revision to Diff 336096.
junparser added a comment.

fix typo.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100107/new/

https://reviews.llvm.org/D100107

Files:
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/test/CodeGen/AArch64/sve-stepvector.ll


Index: llvm/test/CodeGen/AArch64/sve-stepvector.ll
===================================================================
--- llvm/test/CodeGen/AArch64/sve-stepvector.ll
+++ llvm/test/CodeGen/AArch64/sve-stepvector.ll
@@ -49,9 +49,8 @@
 ; CHECK-LABEL: stepvector_nxv4i64:
 ; CHECK:       // %bb.0: // %entry
 ; CHECK-NEXT:    cntd x8
-; CHECK-NEXT:    mov z1.d, x8
+; CHECK-NEXT:    index z1.d, x8, #1
 ; CHECK-NEXT:    index z0.d, #0, #1
-; CHECK-NEXT:    add z1.d, z0.d, z1.d
 ; CHECK-NEXT:    ret
 entry:
   %0 = call <vscale x 4 x i64> @llvm.experimental.stepvector.nxv4i64()
@@ -61,14 +60,13 @@
 define <vscale x 16 x i32> @stepvector_nxv16i32() {
 ; CHECK-LABEL: stepvector_nxv16i32:
 ; CHECK:       // %bb.0: // %entry
-; CHECK-NEXT:    cntw x9
 ; CHECK-NEXT:    cnth x8
+; CHECK-NEXT:    cntw x9
+; CHECK-NEXT:    mov z0.s, w8
+; CHECK-NEXT:    index z1.s, w9, #1
+; CHECK-NEXT:    index z2.s, w8, #1
+; CHECK-NEXT:    add z3.s, z1.s, z0.s
 ; CHECK-NEXT:    index z0.s, #0, #1
-; CHECK-NEXT:    mov z1.s, w9
-; CHECK-NEXT:    mov z3.s, w8
-; CHECK-NEXT:    add z1.s, z0.s, z1.s
-; CHECK-NEXT:    add z2.s, z0.s, z3.s
-; CHECK-NEXT:    add z3.s, z1.s, z3.s
 ; CHECK-NEXT:    ret
 entry:
   %0 = call <vscale x 16 x i32> @llvm.experimental.stepvector.nxv16i32()
Index: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -13433,6 +13433,32 @@
   return DAG.getNode(N->getOpcode(), SDLoc(N), VT, LHS, RHS);
 }
 
+// add(index_vector(zero, step), dup(X)) -> index_vector(X, step)
+static SDValue performAddIndexVectorCombine(SDNode *N, SelectionDAG &DAG) {
+  if (N->getOpcode() != ISD::ADD)
+    return SDValue();
+
+  SDValue IV = N->getOperand(0);
+  SDValue A = N->getOperand(1);
+  // Handle commutivity
+  if (IV.getOpcode() != AArch64ISD::INDEX_VECTOR)
+    std::swap(IV, A);
+  if (IV.getOpcode() != AArch64ISD::INDEX_VECTOR)
+    return SDValue();
+
+  EVT VT = N->getValueType(0);
+  assert(VT.isScalableVector() &&
+         "Only expect scalable vectors for STEP_VECTOR");
+
+  auto *BaseVal = dyn_cast<ConstantSDNode>(IV->getOperand(0));
+  if (BaseVal && BaseVal->isNullValue() &&
+      (A.getOpcode() == AArch64ISD::DUP || A.getOpcode() == ISD::SPLAT_VECTOR))
+    return DAG.getNode(AArch64ISD::INDEX_VECTOR, SDLoc(N), VT, A->getOperand(0),
+                       IV->getOperand(1));
+
+  return SDValue();
+}
+
 static SDValue performAddSubCombine(SDNode *N,
                                     TargetLowering::DAGCombinerInfo &DCI,
                                     SelectionDAG &DAG) {
@@ -13442,6 +13468,10 @@
   if (SDValue Val = performAddDotCombine(N, DAG))
     return Val;
 
+  // Try to combine add with index_vector
+  if (SDValue Val = performAddIndexVectorCombine(N, DAG))
+    return Val;
+
   return performAddSubLongCombine(N, DCI, DAG);
 }
 


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