[llvm] 2410418 - [RISCV] Refactor lowerBUILD_VECTOR splat opcode selection to avoid duplication. NFC. (#185573)

[via llvm-commits]

Author: Jim Lin
Date: 2026-03-11T08:57:57+08:00
New Revision: 2410418d06fc7332e2ff5e138ea094d814235da4

URL: https://github.com/llvm/llvm-project/commit/2410418d06fc7332e2ff5e138ea094d814235da4
DIFF: https://github.com/llvm/llvm-project/commit/2410418d06fc7332e2ff5e138ea094d814235da4.diff

LOG: [RISCV] Refactor lowerBUILD_VECTOR splat opcode selection to avoid duplication. NFC. (#185573)

Hoist the common ANY_EXTEND, DAG.getNode, and convertFromScalableVector
calls out of the duplicated if/else branches. Use a single IsScalar bool
to select between VMV_S_X_VL/VFMV_S_F_VL and VMV_V_X_VL/VFMV_V_F_VL.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVISelLowering.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index f339253af23eb..10dd464a05fa1 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -4724,23 +4724,17 @@ static SDValue lowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG,
     if (auto Gather = matchSplatAsGather(Splat, VT, DL, DAG, Subtarget))
       return Gather;
 
+    if (!VT.isFloatingPoint())
+      Splat = DAG.getNode(ISD::ANY_EXTEND, DL, XLenVT, Splat);
+
     // Prefer vmv.s.x/vfmv.s.f if legal to reduce work and register
     // pressure at high LMUL.
-    if (all_of(Op->ops().drop_front(),
-               [](const SDUse &U) { return U.get().isUndef(); })) {
-      unsigned Opc =
-          VT.isFloatingPoint() ? RISCVISD::VFMV_S_F_VL : RISCVISD::VMV_S_X_VL;
-      if (!VT.isFloatingPoint())
-        Splat = DAG.getNode(ISD::ANY_EXTEND, DL, XLenVT, Splat);
-      Splat = DAG.getNode(Opc, DL, ContainerVT, DAG.getUNDEF(ContainerVT),
-                          Splat, VL);
-      return convertFromScalableVector(VT, Splat, DAG, Subtarget);
-    }
-
+    bool IsScalar = all_of(Op->ops().drop_front(),
+                           [](const SDUse &U) { return U.get().isUndef(); });
     unsigned Opc =
-        VT.isFloatingPoint() ? RISCVISD::VFMV_V_F_VL : RISCVISD::VMV_V_X_VL;
-    if (!VT.isFloatingPoint())
-      Splat = DAG.getNode(ISD::ANY_EXTEND, DL, XLenVT, Splat);
+        VT.isFloatingPoint()
+            ? (IsScalar ? RISCVISD::VFMV_S_F_VL : RISCVISD::VFMV_V_F_VL)
+            : (IsScalar ? RISCVISD::VMV_S_X_VL : RISCVISD::VMV_V_X_VL);
     Splat =
         DAG.getNode(Opc, DL, ContainerVT, DAG.getUNDEF(ContainerVT), Splat, VL);
     return convertFromScalableVector(VT, Splat, DAG, Subtarget);