riscv: fix error: control reaches end of non-void function

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.

diff --git a/gcc/config/riscv/sync.md b/gcc/config/riscv/sync.md
index 6e7c762ac57797e142bfcec3f09f05fa9bd712c7..9fc626267de3840ce15d196bff72440a980fd234 100644 (file)
--- 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))])