[Bug target/113257] -march=native or -mcpu=native are ineffective, but -march=native -mcpu=native works on arm64 M2 Ultra

[sjames at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113257

--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
FWIW, I did try a patch per
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110901#c4 as a quick hack in case
it's the same issue, but it didn't help:
```
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -1421,7 +1421,7 @@ extern const char *host_detect_local_cpu (int argc, const
char **argv);
   CONFIG_TUNE_SPEC

 #define MCPU_TO_MARCH_SPEC \
-   " %{mcpu=*:-march=%:rewrite_mcpu(%{mcpu=*:%*})}"
+   " %{!march=*:%{mcpu=*:-march=%:rewrite_mcpu(%{mcpu=*:%*})}}"

 extern const char *aarch64_rewrite_mcpu (int argc, const char **argv);
 #define MCPU_TO_MARCH_SPEC_FUNCTIONS \
```