[clang] [RISCV] Add missing required features for Zvfbfmin intrinsics (PR #145646)

[Jim Lin via cfe-commits]

https://github.com/tclin914 created https://github.com/llvm/llvm-project/pull/145646

Although `checkRVVTypeSupport` can prevent the use of bf16 vector types without Zvfbfmin, the required features for Zvfbfmin intrinsics may still be needed if bf16 vector types can someday be enabled by other extensions.

>From c5e4f05642da3cad0e3aeac82a18880ad39459dc Mon Sep 17 00:00:00 2001
From: Jim Lin <jim at andestech.com>
Date: Wed, 25 Jun 2025 14:21:17 +0800
Subject: [PATCH] [RISCV] Add missing required features for Zvfbfmin intrinsics

Although `checkRVVTypeSupport` can prevent the use of bf16 vector types
without Zvfbfmin, the required features for Zvfbfmin intrinsics may
still be needed if bf16 vector types can someday be enabled by other
extensions.
---
 clang/include/clang/Basic/riscv_vector.td       | 5 +++--
 clang/test/Sema/rvv-required-features-invalid.c | 7 +++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/clang/include/clang/Basic/riscv_vector.td b/clang/include/clang/Basic/riscv_vector.td
index c6fd8a1a45fd1..c9b310ddced36 100644
--- a/clang/include/clang/Basic/riscv_vector.td
+++ b/clang/include/clang/Basic/riscv_vector.td
@@ -2013,7 +2013,7 @@ let Log2LMUL = [-3, -2, -1, 0, 1, 2] in {
 }
 
 // Zvfbfmin - Vector convert BF16 to FP32
-let Log2LMUL = [-2, -1, 0, 1, 2] in
+let RequiredFeatures = ["zvfbfmin"], Log2LMUL = [-2, -1, 0, 1, 2] in
 def vfwcvtbf16_f_f_v : RVVConvBuiltin<"Fw", "Fwv", "y", "vfwcvtbf16_f">;
 
 let ManualCodegen = [{
@@ -2121,7 +2121,8 @@ let ManualCodegen = [{
     }
 
     // Zvfbfmin - Vector convert FP32 to BF16
-    let Log2LMUL = [-2, -1, 0, 1, 2],
+    let RequiredFeatures = ["zvfbfmin"],
+        Log2LMUL = [-2, -1, 0, 1, 2],
         OverloadedName = "vfncvtbf16_f" in
     defm : RVVConvBuiltinSet<"vfncvtbf16_f_f_w", "y", [["v", "vFwu"]]>;
   }
diff --git a/clang/test/Sema/rvv-required-features-invalid.c b/clang/test/Sema/rvv-required-features-invalid.c
index c96d0e158062b..1e08e4e9e4b65 100644
--- a/clang/test/Sema/rvv-required-features-invalid.c
+++ b/clang/test/Sema/rvv-required-features-invalid.c
@@ -48,3 +48,10 @@ void test_zvfbfwma_vfwmaccbf16(vfloat32m4_t vd, __bf16 vs1, vbfloat16m2_t vs2, s
   // expected-error at -1 {{RISC-V type '__rvv_bfloat16m2_t' requires the 'zvfbfmin' extension}}
   // expected-error at -2 {{builtin requires at least one of the following extensions: zvfbfwma}}
 }
+
+void test_zvfbfmin_vfwcvtbf16(vbfloat16m2_t vs2, size_t vl) {
+  // expected-error at -1 {{RISC-V type 'vbfloat16m2_t' (aka '__rvv_bfloat16m2_t') requires the 'zvfbfmin' extension}}
+  __riscv_vfwcvtbf16_f_f_v_f32m4(vs2, vl);; // expected-error {{RISC-V type 'vbfloat16m2_t' (aka '__rvv_bfloat16m2_t') requires the 'zvfbfmin' extension}}
+  // expected-error at -1 {{RISC-V type '__rvv_bfloat16m2_t' requires the 'zvfbfmin' extension}}
+  // expected-error at -2 {{builtin requires at least one of the following extensions: zvfbfmin}}
+}