[llvm] [RISCV] Only support SPLAT_VECTOR for Zvfhmin when also enable the scalar extension of half fp (PR #88275)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-risc-v

Author: Jianjian Guan (jacquesguan)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/88275.diff


2 Files Affected:

- (modified) llvm/lib/Target/RISCV/RISCVISelLowering.cpp (+2-1) 
- (modified) llvm/test/CodeGen/RISCV/rvv/vsplats-fp.ll (+26-9) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 6e97575c167cd5..56adf08d5aaf81 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -1063,7 +1063,8 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
         setOperationAction({ISD::CONCAT_VECTORS, ISD::INSERT_SUBVECTOR,
                             ISD::EXTRACT_SUBVECTOR, ISD::SCALAR_TO_VECTOR},
                            VT, Custom);
-        setOperationAction(ISD::SPLAT_VECTOR, VT, Custom);
+        if (Subtarget.hasStdExtZfhminOrZhinxmin())
+          setOperationAction(ISD::SPLAT_VECTOR, VT, Custom);
         // load/store
         setOperationAction({ISD::LOAD, ISD::STORE}, VT, Custom);
 
diff --git a/llvm/test/CodeGen/RISCV/rvv/vsplats-fp.ll b/llvm/test/CodeGen/RISCV/rvv/vsplats-fp.ll
index 707ef8a94432d3..1aebd32cefca6a 100644
--- a/llvm/test/CodeGen/RISCV/rvv/vsplats-fp.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/vsplats-fp.ll
@@ -1,19 +1,36 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=riscv32 -mattr=+f,+d,+zfh,+zvfh,+v -target-abi ilp32d -verify-machineinstrs < %s \
-; RUN:   | FileCheck %s --check-prefixes=CHECK,OPTIMIZED
+; RUN:   | FileCheck %s --check-prefixes=CHECK,ZVFH,OPTIMIZED
 ; RUN: llc -mtriple=riscv64 -mattr=+f,+d,+zfh,+zvfh,+v -target-abi lp64d -verify-machineinstrs < %s \
-; RUN:   | FileCheck %s --check-prefixes=CHECK,OPTIMIZED
+; RUN:   | FileCheck %s --check-prefixes=CHECK,ZVFH,OPTIMIZED
 ; RUN: llc -mtriple=riscv32 -mattr=+f,+d,+zfh,+zvfh,+v,+no-optimized-zero-stride-load -target-abi ilp32d -verify-machineinstrs < %s \
-; RUN:   | FileCheck %s --check-prefixes=CHECK,NOT-OPTIMIZED
+; RUN:   | FileCheck %s --check-prefixes=CHECK,ZVFH,NOT-OPTIMIZED
 ; RUN: llc -mtriple=riscv64 -mattr=+f,+d,+zfh,+zvfh,+v,+no-optimized-zero-stride-load -target-abi lp64d -verify-machineinstrs < %s \
-; RUN:   | FileCheck %s --check-prefixes=CHECK,NOT-OPTIMIZED
+; RUN:   | FileCheck %s --check-prefixes=CHECK,ZVFH,NOT-OPTIMIZED
+; RUN: llc -mtriple=riscv32 -mattr=+f,+d,+zfh,+zvfhmin,+v -target-abi ilp32d -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=CHECK,ZVFHMIN,OPTIMIZED
+; RUN: llc -mtriple=riscv64 -mattr=+f,+d,+zfh,+zvfhmin,+v -target-abi lp64d -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=CHECK,ZVFHMIN,OPTIMIZED
+; RUN: llc -mtriple=riscv32 -mattr=+f,+d,+zfh,+zvfhmin,+v,+no-optimized-zero-stride-load -target-abi ilp32d -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=CHECK,ZVFHMIN,NOT-OPTIMIZED
+; RUN: llc -mtriple=riscv64 -mattr=+f,+d,+zfh,+zvfhmin,+v,+no-optimized-zero-stride-load -target-abi lp64d -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=CHECK,ZVFHMIN,NOT-OPTIMIZED
 
 define <vscale x 8 x half> @vsplat_nxv8f16(half %f) {
-; CHECK-LABEL: vsplat_nxv8f16:
-; CHECK:       # %bb.0:
-; CHECK-NEXT:    vsetvli a0, zero, e16, m2, ta, ma
-; CHECK-NEXT:    vfmv.v.f v8, fa0
-; CHECK-NEXT:    ret
+; ZVFH-LABEL: vsplat_nxv8f16:
+; ZVFH:       # %bb.0:
+; ZVFH-NEXT:    vsetvli a0, zero, e16, m2, ta, ma
+; ZVFH-NEXT:    vfmv.v.f v8, fa0
+; ZVFH-NEXT:    ret
+;
+; ZVFHMIN-LABEL: vsplat_nxv8f16:
+; ZVFHMIN:       # %bb.0:
+; ZVFHMIN-NEXT:    fcvt.s.h fa5, fa0
+; ZVFHMIN-NEXT:    vsetvli a0, zero, e32, m4, ta, ma
+; ZVFHMIN-NEXT:    vfmv.v.f v12, fa5
+; ZVFHMIN-NEXT:    vsetvli zero, zero, e16, m2, ta, ma
+; ZVFHMIN-NEXT:    vfncvt.f.f.w v8, v12
+; ZVFHMIN-NEXT:    ret
   %head = insertelement <vscale x 8 x half> poison, half %f, i32 0
   %splat = shufflevector <vscale x 8 x half> %head, <vscale x 8 x half> poison, <vscale x 8 x i32> zeroinitializer
   ret <vscale x 8 x half> %splat

``````````

</details>


https://github.com/llvm/llvm-project/pull/88275