[gcc13 backport 12/12] riscv: fix error: control reaches end of non-void function

[Patrick O'Neill]

From: Martin Liska <mli...@suse.cz>

Fixes:
gcc/config/riscv/sync.md:66:1: error: control reaches end of non-void function 
[-Werror=return-type]
66 |   [(set (attr "length") (const_int 4))])
   | ^

        PR target/109713

gcc/ChangeLog:

        * config/riscv/sync.md: Add gcc_unreachable to a switch.
---
 gcc/config/riscv/sync.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/config/riscv/sync.md b/gcc/config/riscv/sync.md
index 6e7c762ac57..9fc626267de 100644
--- a/gcc/config/riscv/sync.md
+++ b/gcc/config/riscv/sync.md
@@ -62,6 +62,8 @@
        return "fence\tr,rw";
     else if (model == MEMMODEL_RELEASE)
        return "fence\trw,w";
+    else
+       gcc_unreachable ();
   }
   [(set (attr "length") (const_int 4))])
 
-- 
2.34.1