[PATCH] D120963: [RISCV] Fix incorrect codegen introduced by D119688.

[Zakk Chen via Phabricator via llvm-commits]

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We should not emit a tail agnostic vlse for a tail undisturbed vmv.s.x

In D119688 <https://reviews.llvm.org/D119688>:

- if (IsScalarMove && !Node->getOperand(0).isUndef())

+    bool HasPassthruOperand = Node->getOpcode() != ISD::SPLAT_VECTOR;
+    if (HasPassthruOperand && !IsScalarMove &&
!Node->getOperand(0).isUndef())

  break;

The IsScalarMove check in the if statement had been changed.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D120963

Files:
  llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
  llvm/test/CodeGen/RISCV/rvv/vmv.s.x-rv64.ll


Index: llvm/test/CodeGen/RISCV/rvv/vmv.s.x-rv64.ll
===================================================================
--- llvm/test/CodeGen/RISCV/rvv/vmv.s.x-rv64.ll
+++ llvm/test/CodeGen/RISCV/rvv/vmv.s.x-rv64.ll
@@ -291,8 +291,9 @@
 define <vscale x 1 x i64> @intrinsic_vmv.s.x_x_nxv1i64_bug(<vscale x 1 x i64> %0, i64* %1) nounwind {
 ; CHECK-LABEL: intrinsic_vmv.s.x_x_nxv1i64_bug:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    vsetivli zero, 1, e64, m1, ta, mu
-; CHECK-NEXT:    vlse64.v v8, (a0), zero
+; CHECK-NEXT:    ld a0, 0(a0)
+; CHECK-NEXT:    vsetivli zero, 1, e64, m1, tu, mu
+; CHECK-NEXT:    vmv.s.x v8, a0
 ; CHECK-NEXT:    ret
 entry:
   %a = load i64, i64* %1, align 8
Index: llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -1633,7 +1633,7 @@
     bool IsScalarMove = Node->getOpcode() == RISCVISD::VMV_S_X_VL ||
                         Node->getOpcode() == RISCVISD::VFMV_S_F_VL;
     bool HasPassthruOperand = Node->getOpcode() != ISD::SPLAT_VECTOR;
-    if (HasPassthruOperand && !IsScalarMove && !Node->getOperand(0).isUndef())
+    if (HasPassthruOperand && !Node->getOperand(0).isUndef())
       break;
     SDValue Src = HasPassthruOperand ? Node->getOperand(1) : Node->getOperand(0);
     auto *Ld = dyn_cast<LoadSDNode>(Src);


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