1 files changed, 28 insertions, 9 deletions
diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
index 613cfb5..d96136c 100644
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
@@ -2385,13 +2385,6 @@ SDValue LoongArchTargetLowering::lowerBF16_TO_FP(SDValue Op,
   return Res;
 }
 
-static bool isConstantBUILD_VECTOR(const BuildVectorSDNode *Op) {
-  for (unsigned i = 0; i < Op->getNumOperands(); ++i)
-    if (isIntOrFPConstant(Op->getOperand(i)))
-      return true;
-  return false;
-}
-
 // Lower BUILD_VECTOR as broadcast load (if possible).
 // For example:
 //   %a = load i8, ptr %ptr
@@ -2441,10 +2434,14 @@ SDValue LoongArchTargetLowering::lowerBUILD_VECTOR(SDValue Op,
                                                    SelectionDAG &DAG) const {
   BuildVectorSDNode *Node = cast<BuildVectorSDNode>(Op);
   EVT ResTy = Op->getValueType(0);
+  unsigned NumElts = ResTy.getVectorNumElements();
   SDLoc DL(Op);
   APInt SplatValue, SplatUndef;
   unsigned SplatBitSize;
   bool HasAnyUndefs;
+  bool IsConstant = false;
+  bool UseSameConstant = true;
+  SDValue ConstantValue;
   bool Is128Vec = ResTy.is128BitVector();
   bool Is256Vec = ResTy.is256BitVector();
 
@@ -2495,13 +2492,35 @@ SDValue LoongArchTargetLowering::lowerBUILD_VECTOR(SDValue Op,
   if (DAG.isSplatValue(Op, /*AllowUndefs=*/false))
     return Op;
 
-  if (!isConstantBUILD_VECTOR(Node)) {
+  for (unsigned i = 0; i < NumElts; ++i) {
+    SDValue Opi = Node->getOperand(i);
+    if (isIntOrFPConstant(Opi)) {
+      IsConstant = true;
+      if (!ConstantValue.getNode())
+        ConstantValue = Opi;
+      else if (ConstantValue != Opi)
+        UseSameConstant = false;
+    }
+  }
+
+  // If the type of BUILD_VECTOR is v2f64, custom legalizing it has no benefits.
+  if (IsConstant && UseSameConstant && ResTy != MVT::v2f64) {
+    SDValue Result = DAG.getSplatBuildVector(ResTy, DL, ConstantValue);
+    for (unsigned i = 0; i < NumElts; ++i) {
+      SDValue Opi = Node->getOperand(i);
+      if (!isIntOrFPConstant(Opi))
+        Result = DAG.getNode(ISD::INSERT_VECTOR_ELT, DL, ResTy, Result, Opi,
+                             DAG.getConstant(i, DL, Subtarget.getGRLenVT()));
+    }
+    return Result;
+  }
+
+  if (!IsConstant) {
     // Use INSERT_VECTOR_ELT operations rather than expand to stores.
     // The resulting code is the same length as the expansion, but it doesn't
     // use memory operations.
     assert(ResTy.isVector());
 
-    unsigned NumElts = ResTy.getVectorNumElements();
     SDValue Op0 = Node->getOperand(0);
     SDValue Vector = DAG.getUNDEF(ResTy);