From ecabba04a35432ad94447d199cf6127d57415456 Mon Sep 17 00:00:00 2001
From: Philip Reames <preames@rivosinc.com>
Date: Tue, 13 Dec 2022 09:02:01 -0800
Subject: [PATCH] [RISCV] Use lowerScalarInsert when folding op into reduction
 [nfc]

This doesn't cause any functional change since this is being applied to a insert generated by the same routine.  This is mostly about consolidating the logic for vmv.s.x into one place to simplify future changes.
---
 llvm/lib/Target/RISCV/RISCVISelLowering.cpp | 26 +++++++--------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 02345d89788a4..df8ec9a2927a6 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -8007,7 +8007,8 @@ void RISCVTargetLowering::ReplaceNodeResults(SDNode *N,
 }
 
 // Try to fold (<bop> x, (reduction.<bop> vec, start))
-static SDValue combineBinOpToReduce(SDNode *N, SelectionDAG &DAG) {
+static SDValue combineBinOpToReduce(SDNode *N, SelectionDAG &DAG,
+                                    const RISCVSubtarget &Subtarget) {
   auto BinOpToRVVReduce = [](unsigned Opc) {
     switch (Opc) {
     default:
@@ -8084,20 +8085,11 @@ static SDValue combineBinOpToReduce(SDNode *N, SelectionDAG &DAG) {
   if (!ScalarV.hasOneUse())
     return SDValue();
 
-  EVT SplatVT = ScalarV.getValueType();
   SDValue NewStart = N->getOperand(1 - ReduceIdx);
-  unsigned SplatOpc = RISCVISD::VFMV_S_F_VL;
-  if (SplatVT.isInteger()) {
-    auto *C = dyn_cast<ConstantSDNode>(NewStart.getNode());
-    if (!C || C->isZero() || !isInt<5>(C->getSExtValue()))
-      SplatOpc = RISCVISD::VMV_S_X_VL;
-    else
-      SplatOpc = RISCVISD::VMV_V_X_VL;
-  }
 
   SDValue NewScalarV =
-      DAG.getNode(SplatOpc, SDLoc(N), SplatVT, ScalarV.getOperand(0), NewStart,
-                  ScalarV.getOperand(2));
+    lowerScalarInsert(NewStart, ScalarV.getOperand(2), ScalarV.getSimpleValueType(),
+                      SDLoc(N), DAG, Subtarget);
   SDValue NewReduce =
       DAG.getNode(Reduce.getOpcode(), SDLoc(Reduce), Reduce.getValueType(),
                   Reduce.getOperand(0), Reduce.getOperand(1), NewScalarV,
@@ -8299,7 +8291,7 @@ static SDValue performADDCombine(SDNode *N, SelectionDAG &DAG,
     return V;
   if (SDValue V = transformAddShlImm(N, DAG, Subtarget))
     return V;
-  if (SDValue V = combineBinOpToReduce(N, DAG))
+  if (SDValue V = combineBinOpToReduce(N, DAG, Subtarget))
     return V;
   // fold (add (select lhs, rhs, cc, 0, y), x) ->
   //      (select lhs, rhs, cc, x, (add x, y))
@@ -8453,7 +8445,7 @@ static SDValue performANDCombine(SDNode *N,
     return DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, And);
   }
 
-  if (SDValue V = combineBinOpToReduce(N, DAG))
+  if (SDValue V = combineBinOpToReduce(N, DAG, Subtarget))
     return V;
 
   if (DCI.isAfterLegalizeDAG())
@@ -8469,7 +8461,7 @@ static SDValue performORCombine(SDNode *N, TargetLowering::DAGCombinerInfo &DCI,
                                 const RISCVSubtarget &Subtarget) {
   SelectionDAG &DAG = DCI.DAG;
 
-  if (SDValue V = combineBinOpToReduce(N, DAG))
+  if (SDValue V = combineBinOpToReduce(N, DAG, Subtarget))
     return V;
 
   if (DCI.isAfterLegalizeDAG())
@@ -8497,7 +8489,7 @@ static SDValue performXORCombine(SDNode *N, SelectionDAG &DAG,
                        DAG.getConstant(~1, DL, MVT::i64), N0.getOperand(1));
   }
 
-  if (SDValue V = combineBinOpToReduce(N, DAG))
+  if (SDValue V = combineBinOpToReduce(N, DAG, Subtarget))
     return V;
   // fold (xor (select cond, 0, y), x) ->
   //      (select cond, x, (xor x, y))
@@ -9717,7 +9709,7 @@ SDValue RISCVTargetLowering::PerformDAGCombine(SDNode *N,
   case ISD::SMIN:
   case ISD::FMAXNUM:
   case ISD::FMINNUM:
-    return combineBinOpToReduce(N, DAG);
+    return combineBinOpToReduce(N, DAG, Subtarget);
   case ISD::SETCC:
     return performSETCCCombine(N, DAG, Subtarget);
   case ISD::SIGN_EXTEND_INREG: