[llvm] 33b61c5 - [RISCV] Fix incorrect codegen introduced by D119688.

[Zakk Chen via llvm-commits]

Author: Zakk Chen
Date: 2022-03-05T06:10:26-08:00
New Revision: 33b61c567883f81c97c26ccdb2afe405e4de794c

URL: https://github.com/llvm/llvm-project/commit/33b61c567883f81c97c26ccdb2afe405e4de794c
DIFF: https://github.com/llvm/llvm-project/commit/33b61c567883f81c97c26ccdb2afe405e4de794c.diff

LOG: [RISCV] Fix incorrect codegen introduced by D119688.

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

In 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.

Differential Revision: https://reviews.llvm.org/D120963

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
index 0bb6ac8b7b011..93f093c93b94a 100644
--- a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -1633,7 +1633,7 @@ void RISCVDAGToDAGISel::Select(SDNode *Node) {
     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);

diff  --git a/llvm/test/CodeGen/RISCV/rvv/vmv.s.x-rv64.ll b/llvm/test/CodeGen/RISCV/rvv/vmv.s.x-rv64.ll
index 3472a83e0ff4f..3d876dc257ddd 100644
--- a/llvm/test/CodeGen/RISCV/rvv/vmv.s.x-rv64.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/vmv.s.x-rv64.ll
@@ -291,8 +291,9 @@ entry:
 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