[llvm] 258bb45 - [RISCV] Without Zfh, promote f16 inputs before creating RISCVISD::FCVT_W(U)_RV64 nodes.

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2022-12-07T12:25:30-08:00
New Revision: 258bb453fb84b2f149a51adf9ebfd535f4288fe2

URL: https://github.com/llvm/llvm-project/commit/258bb453fb84b2f149a51adf9ebfd535f4288fe2
DIFF: https://github.com/llvm/llvm-project/commit/258bb453fb84b2f149a51adf9ebfd535f4288fe2.diff

LOG: [RISCV] Without Zfh, promote f16 inputs before creating RISCVISD::FCVT_W(U)_RV64 nodes.

This allows us to remove a couple more Zfhmin isel patterns.

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 6eb85d4009b8..5cb220cd8fe2 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -1959,7 +1959,7 @@ static SDValue lowerFP_TO_INT_SAT(SDValue Op, SelectionDAG &DAG,
   bool IsSigned = Op.getOpcode() == ISD::FP_TO_SINT_SAT;
 
   if (!DstVT.isVector()) {
-    // In absense, of Zfh, promote f16 to f32, then saturate the result.
+    // In absense of Zfh, promote f16 to f32, then saturate the result.
     if (Src.getSimpleValueType() == MVT::f16 && !Subtarget.hasStdExtZfh()) {
       Src = DAG.getNode(ISD::FP_EXTEND, SDLoc(Op), MVT::f32, Src);
     }
@@ -7480,16 +7480,27 @@ void RISCVTargetLowering::ReplaceNodeResults(SDNode *N,
       if (!isTypeLegal(Op0.getValueType()))
         return;
       if (IsStrict) {
+        SDValue Chain = N->getOperand(0);
+        // In absense of Zfh, promote f16 to f32, then convert.
+        if (Op0.getValueType() == MVT::f16 && !Subtarget.hasStdExtZfh()) {
+          Op0 = DAG.getNode(ISD::STRICT_FP_EXTEND, DL, {MVT::f32, MVT::Other},
+                            {Chain, Op0});
+          Chain = Op0.getValue(1);
+        }
         unsigned Opc = IsSigned ? RISCVISD::STRICT_FCVT_W_RV64
                                 : RISCVISD::STRICT_FCVT_WU_RV64;
         SDVTList VTs = DAG.getVTList(MVT::i64, MVT::Other);
         SDValue Res = DAG.getNode(
-            Opc, DL, VTs, N->getOperand(0), Op0,
+            Opc, DL, VTs, Chain, Op0,
             DAG.getTargetConstant(RISCVFPRndMode::RTZ, DL, MVT::i64));
         Results.push_back(DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, Res));
         Results.push_back(Res.getValue(1));
         return;
       }
+      // In absense of Zfh, promote f16 to f32, then convert.
+      if (Op0.getValueType() == MVT::f16 && !Subtarget.hasStdExtZfh())
+        Op0 = DAG.getNode(ISD::FP_EXTEND, DL, MVT::f32, Op0);
+
       unsigned Opc = IsSigned ? RISCVISD::FCVT_W_RV64 : RISCVISD::FCVT_WU_RV64;
       SDValue Res =
           DAG.getNode(Opc, DL, MVT::i64, Op0,

diff  --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZfh.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZfh.td
index f50bb59f4bc5..1ce7b2398c45 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoZfh.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZfh.td
@@ -464,7 +464,4 @@ def : Pat<(i64 (any_llround FPR16:$rs1)), (FCVT_L_S (FCVT_S_H $rs1), 0b100)>;
 // [u]int->fp. Match GCC and default to using dynamic rounding mode.
 def : Pat<(any_sint_to_fp (i64 GPR:$rs1)), (FCVT_H_S (FCVT_S_L $rs1, 0b111), 0b111)>;
 def : Pat<(any_uint_to_fp (i64 GPR:$rs1)), (FCVT_H_S (FCVT_S_LU $rs1, 0b111), 0b111)>;
-
-def : Pat<(riscv_any_fcvt_w_rv64 FPR16:$rs1, timm:$frm),  (FCVT_W_S (FCVT_S_H $rs1), timm:$frm)>;
-def : Pat<(riscv_any_fcvt_wu_rv64 FPR16:$rs1, timm:$frm), (FCVT_WU_S (FCVT_S_H $rs1), timm:$frm)>;
 } // Predicates = [HasStdExtZfhmin, NoStdExtZfh, IsRV64]