[to-be-committed][RISC-V][PR target/121113] Handle HFmode in various insn reservations

[Jeff Law]

So this is a minor bug in a few DFA descriptions such as the Xiangshan 
and a couple of the SiFive descriptions.

While Xiangshan covers every insn type, some of the reservations check 
the mode of the operation.   Concretely the fdiv/fsqrt unit reservations 
vary based on the mode.  They handled DF/SF, but not HF (the relevant 
iterators don't include BF).

This patch just adds HF support with the same characteristics as SF. 
Those who know these designs better could perhaps improve the 
reservation, but this at least keeps us from aborting.

I did check the other published DFAs for mode dependent reservations. 
That's show I found the p400/p600 issue.

Tested in my tester, waiting for CI to render its verdict before pushing.

Jeffdiff --git a/gcc/config/riscv/sifive-p400.md b/gcc/config/riscv/sifive-p400.md
index ed8b8ec9da7b..d6f6e2a3b6c0 100644
--- a/gcc/config/riscv/sifive-p400.md
+++ b/gcc/config/riscv/sifive-p400.md
@@ -153,10 +153,13 @@ (define_insn_reservation "sifive_p400_fmove" 2
        (eq_attr "type" "fmove,fcvt"))
   "p400_float_pipe,sifive_p400_fpu")
 
+;; We need something for HF so that we don't abort during
+;; scheduling if someone was to ask for p400 scheduling, but
+;; enable the various HF mode extensions.
 (define_insn_reservation "sifive_p400_fdiv_s" 18
   (and (eq_attr "tune" "sifive_p400")
        (eq_attr "type" "fdiv,fsqrt")
-       (eq_attr "mode" "SF"))
+       (eq_attr "mode" "HF,SF"))
   "sifive_p400_FM, sifive_p400_fdiv*5")
 
 (define_insn_reservation "sifive_p400_fdiv_d" 31
diff --git a/gcc/config/riscv/sifive-p600.md b/gcc/config/riscv/sifive-p600.md
index 240134976fa1..ff51149f9b70 100644
--- a/gcc/config/riscv/sifive-p600.md
+++ b/gcc/config/riscv/sifive-p600.md
@@ -157,10 +157,13 @@ (define_insn_reservation "sifive_p600_fmove" 2
        (eq_attr "type" "fmove,fcvt"))
   "float_pipe,sifive_p600_fpu")
 
+;; We need something for HF so that we don't abort during
+;; scheduling if someone was to ask for p600 scheduling, but
+;; enable the various HF mode extensions.
 (define_insn_reservation "sifive_p600_fdiv_s" 11
   (and (eq_attr "tune" "sifive_p600")
        (eq_attr "type" "fdiv,fsqrt")
-       (eq_attr "mode" "SF"))
+       (eq_attr "mode" "HF,SF"))
   "sifive_p600_FM, sifive_p600_fdiv*5")
 
 (define_insn_reservation "sifive_p600_fdiv_d" 19
diff --git a/gcc/config/riscv/xiangshan.md b/gcc/config/riscv/xiangshan.md
index 34b4a8f1f3fc..617914087815 100644
--- a/gcc/config/riscv/xiangshan.md
+++ b/gcc/config/riscv/xiangshan.md
@@ -144,13 +144,13 @@ (define_insn_reservation "xiangshan_f2i" 3
 (define_insn_reservation "xiangshan_sfdiv" 11
   (and (eq_attr "tune" "xiangshan")
        (eq_attr "type" "fdiv")
-       (eq_attr "mode" "SF"))
+       (eq_attr "mode" "HF,SF"))
   "xs_fmisc_rs")
 
 (define_insn_reservation "xiangshan_sfsqrt" 17
   (and (eq_attr "tune" "xiangshan")
        (eq_attr "type" "fsqrt")
-       (eq_attr "mode" "SF"))
+       (eq_attr "mode" "HF,SF"))
   "xs_fmisc_rs")
 
 (define_insn_reservation "xiangshan_dfdiv" 21
diff --git a/gcc/testsuite/gcc.target/riscv/pr121113.c 
b/gcc/testsuite/gcc.target/riscv/pr121113.c
new file mode 100644
index 000000000000..091fa828ef32
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/pr121113.c
@@ -0,0 +1,5 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-std=c23 -mcpu=xiangshan-kunminghu" } */
+
+_Float16 f, g;
+void foo() { f /= g; }