[PATCH] RISC-V: Check if we can vec_extract [PR121510].

[Robin Dapp]

Hi,

For Zvfhmin a vector mode exists but the corresponding vec_extract does
not.  This patch checks that a vec_extract is available and otherwise
falls back to standard handling.

I cannot test myself right now so handing it off to the CI :)

Regards
Robin

        PR target/121510

gcc/ChangeLog:

        * config/riscv/riscv.cc (riscv_legitimize_move): Check if we can
        vec_extract.

gcc/testsuite/ChangeLog:

        * gcc.target/riscv/rvv/autovec/pr121510.c: New test.
---
gcc/config/riscv/riscv.cc                      |  3 ++-
.../gcc.target/riscv/rvv/autovec/pr121510.c    | 18 ++++++++++++++++++
2 files changed, 20 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/pr121510.c

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index d5a656c3781..07d40f459e3 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -3686,7 +3686,8 @@ riscv_legitimize_move (machine_mode mode, rtx dest, rtx 
src)
         not enabled.  In that case we just want to let the standard
         expansion path run.  */
      if (riscv_vector::get_vector_mode (smode, nunits).exists (&vmode)
-         && gen_lowpart_common (vmode, SUBREG_REG (src)))
+         && gen_lowpart_common (vmode, SUBREG_REG (src))
+         && convert_optab_handler (vec_extract_optab, vmode, smode))
        {
          rtx v = gen_lowpart (vmode, SUBREG_REG (src));
          rtx int_reg = dest;
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr121510.c 
b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr121510.c
new file mode 100644
index 00000000000..b5d02116c98
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr121510.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv_zvfhmin -O3" } */
+
+long *print_bfloat_block;
+void ftoastr(float);
+void print_bfloat() {
+  for (;;) {
+    long j;
+    union {
+      _Float16 x;
+      char b[]
+    } u;
+    j = 0;
+    for (; j < sizeof 0; j++)
+      u.b[j] = print_bfloat_block[j];
+    ftoastr(u.x);
+  }
+}
--
2.51.0