From 80a7754c359e6d9db2c7ff32bfac5e9422af14ce Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@sifive.com>
Date: Wed, 11 Jan 2023 19:01:46 -0800
Subject: [PATCH] [RISCV] Move FP store of extractelt pattern to DAGCombine.

This makes it the same as integer.
---
 llvm/lib/Target/RISCV/RISCVISelLowering.cpp        | 15 ++++++++++-----
 llvm/lib/Target/RISCV/RISCVInstrInfoVSDPatterns.td |  9 ---------
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 74c4bba..169ff9d 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -10435,14 +10435,19 @@ SDValue RISCVTargetLowering::PerformDAGCombine(SDNode *N,
   case ISD::STORE: {
     auto *Store = cast<StoreSDNode>(N);
     SDValue Val = Store->getValue();
-    // Combine store of vmv.x.s to vse with VL of 1.
-    // FIXME: Support FP.
-    if (Val.getOpcode() == RISCVISD::VMV_X_S) {
+    // Combine store of vmv.x.s/vfmv.f.s to vse with VL of 1.
+    // vfmv.f.s is represented as extract element from 0. Match it late to avoid
+    // any illegal types.
+    if (Val.getOpcode() == RISCVISD::VMV_X_S ||
+        (DCI.isAfterLegalizeDAG() &&
+         Val.getOpcode() == ISD::EXTRACT_VECTOR_ELT &&
+         isNullConstant(Val.getOperand(1)))) {
       SDValue Src = Val.getOperand(0);
       MVT VecVT = Src.getSimpleValueType();
       EVT MemVT = Store->getMemoryVT();
-      // The memory VT and the element type must match.
-      if (MemVT == VecVT.getVectorElementType()) {
+      // VecVT should be scalable and memory VT should match the element type.
+      if (VecVT.isScalableVector() &&
+          MemVT == VecVT.getVectorElementType()) {
         SDLoc DL(N);
         MVT MaskVT = getMaskTypeFor(VecVT);
         return DAG.getStoreVP(
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoVSDPatterns.td b/llvm/lib/Target/RISCV/RISCVInstrInfoVSDPatterns.td
index aec0216..c07bb77 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoVSDPatterns.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoVSDPatterns.td
@@ -1035,15 +1035,6 @@ foreach fvti = AllFloatVectors in {
 //===----------------------------------------------------------------------===//
 let Predicates = [HasVInstructionsAnyF] in
 foreach vti = AllFloatVectors in {
-  // Fold store of vmv.f.s to a vse with VL=1.
-  defvar store_instr = !cast<Instruction>("PseudoVSE"#vti.SEW#"_V_"#vti.LMul.MX);
-
-  let AddedComplexity = 2 in {
-  // Add complexity to increase the priority of this pattern being matched.
-  def : Pat<(store (extractelt (vti.Vector vti.RegClass:$rs2), 0), GPR:$rs1),
-            (store_instr vti.RegClass:$rs2, GPR:$rs1, 1, vti.Log2SEW)>;
-  }
-
   defvar vmv_f_s_inst = !cast<Instruction>(!strconcat("PseudoVFMV_",
                                                        vti.ScalarSuffix,
                                                        "_S_", vti.LMul.MX));
-- 
2.7.4