[PATCH 1/2] RISC-V: Allow extension name contain digit

[Kito Cheng]

RISC-V spec only allow alphabetical name for extension before, however
vector extension add several extension named with digits, so we try to
extend the naming rule.

Ref:
https://github.com/riscv/riscv-isa-manual/pull/718

gcc/ChangeLog:

        * common/config/riscv/riscv-common.c
        (riscv_subset_list::parse_multiletter_ext): Allow ext. name has
        digit.
---
 gcc/common/config/riscv/riscv-common.c | 42 +++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/gcc/common/config/riscv/riscv-common.c 
b/gcc/common/config/riscv/riscv-common.c
index b8dd0aeac3e..31b1c833965 100644
--- a/gcc/common/config/riscv/riscv-common.c
+++ b/gcc/common/config/riscv/riscv-common.c
@@ -760,24 +760,58 @@ riscv_subset_list::parse_multiletter_ext (const char *p,
       bool explicit_version_p = false;
       char *ext;
       char backup;
+      size_t len;
+      size_t end_of_version_pos, i;
+      bool found_any_number = false;
+      bool found_minor_version = false;
 
-      while (*++q != '\0' && *q != '_' && !ISDIGIT (*q))
+      /* Parse until end of this extension including version number.  */
+      while (*++q != '\0' && *q != '_')
        ;
 
       backup = *q;
       *q = '\0';
-      ext = xstrdup (subset);
+      len = q - subset;
       *q = backup;
 
+      end_of_version_pos = len;
+      /* Find the begin of version string.  */
+      for (i = len -1; i > 0; --i)
+       {
+         if (ISDIGIT (subset[i]))
+           {
+             found_any_number = true;
+             continue;
+           }
+         /* Might be version seperator, but need to check one more char,
+            we only allow <major>p<minor>, so we could stop parsing if found
+            any more `p`.  */
+         if (subset[i] == 'p' &&
+             !found_minor_version &&
+             found_any_number && ISDIGIT (subset[i-1]))
+           {
+             found_minor_version = true;
+             continue;
+           }
+
+         end_of_version_pos = i + 1;
+         break;
+       }
+
+      backup = subset[end_of_version_pos];
+      subset[end_of_version_pos] = '\0';
+      ext = xstrdup (subset);
+      subset[end_of_version_pos] = backup;
+
       end_of_version
-       = parsing_subset_version (ext, q, &major_version, &minor_version,
+       = parsing_subset_version (ext, subset + end_of_version_pos, 
&major_version, &minor_version,
                                  /* std_ext_p= */ false, &explicit_version_p);
       free (ext);
 
       if (end_of_version == NULL)
        return NULL;
 
-      *q = '\0';
+      subset[end_of_version_pos] = '\0';
 
       if (strlen (subset) == 1)
        {
-- 
2.34.0