[RISCV] Support STRICT_FP_ROUND and STRICT_FP_EXTEND when only have Zvfhmin (#68559)

This patch supports STRICT_FP_ROUND and STRICT_FP_EXTEND when we only
have Zvfhmin but no Zvfh.

Author: jacquesguan

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -942,6 +942,8 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
         if (!isTypeLegal(VT))
           continue;
         setOperationAction({ISD::FP_ROUND, ISD::FP_EXTEND}, VT, Custom);
+        setOperationAction({ISD::STRICT_FP_ROUND, ISD::STRICT_FP_EXTEND}, VT,
+                           Custom);
         setOperationAction({ISD::VP_FP_ROUND, ISD::VP_FP_EXTEND}, VT, Custom);
         setOperationAction({ISD::VP_MERGE, ISD::VP_SELECT, ISD::SELECT}, VT,
                            Custom);
@@ -1154,6 +1156,8 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
         if (VT.getVectorElementType() == MVT::f16 &&
             !Subtarget.hasVInstructionsF16()) {
           setOperationAction({ISD::FP_ROUND, ISD::FP_EXTEND}, VT, Custom);
+          setOperationAction({ISD::STRICT_FP_ROUND, ISD::STRICT_FP_EXTEND}, VT,
+                             Custom);
           setOperationAction({ISD::VP_FP_ROUND, ISD::VP_FP_EXTEND}, VT, Custom);
           setOperationAction(
               {ISD::VP_MERGE, ISD::VP_SELECT, ISD::VSELECT, ISD::SELECT}, VT,

llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vfptrunc-constrained-sdnode.ll

@@ -3,6 +3,10 @@
 ; RUN:     -verify-machineinstrs < %s | FileCheck %s
 ; RUN: llc -mtriple=riscv64 -mattr=+d,+zfh,+zvfh,+v -target-abi=lp64d \
 ; RUN:     -verify-machineinstrs < %s | FileCheck %s
+; RUN: llc -mtriple=riscv32 -mattr=+d,+zfh,+zvfhmin,+v -target-abi=ilp32d \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s
+; RUN: llc -mtriple=riscv64 -mattr=+d,+zfh,+zvfhmin,+v -target-abi=lp64d \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s
 
 declare <2 x float> @llvm.experimental.constrained.fptrunc.v2f32.v2f64(<2 x double>, metadata, metadata)
 define <2 x float> @vfptrunc_v2f64_v2f32(<2 x double> %va) strictfp {

llvm/test/CodeGen/RISCV/rvv/vfptrunc-constrained-sdnode.ll

@@ -3,6 +3,10 @@
 ; RUN:     -verify-machineinstrs < %s | FileCheck %s
 ; RUN: llc -mtriple=riscv64 -mattr=+d,+zfh,+zvfh,+v -target-abi=lp64d \
 ; RUN:     -verify-machineinstrs < %s | FileCheck %s
+; RUN: llc -mtriple=riscv32 -mattr=+d,+zfh,+zvfhmin,+v -target-abi=ilp32d \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s
+; RUN: llc -mtriple=riscv64 -mattr=+d,+zfh,+zvfhmin,+v -target-abi=lp64d \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s
 
 declare <vscale x 1 x float> @llvm.experimental.constrained.fptrunc.nxv1f32.nxv1f64(<vscale x 1 x double>, metadata, metadata)
 define <vscale x 1 x float> @vfptrunc_nxv1f64_nxv1f32(<vscale x 1 x double> %va) strictfp {