[PATCH] LoongArch: Fix an ODR violation

[Xi Ruoyao]

When bootstrapping GCC 14 --with-build-config=bootstrap-lto, an ODR
violation is detected:

    ../../gcc/config/loongarch/loongarch-opts.cc:57: warning:
    'abi_minimal_isa' violates the C++ One Definition Rule [-Wodr]
    57 | abi_minimal_isa[N_ABI_BASE_TYPES][N_ABI_EXT_TYPES];
    ../../gcc/config/loongarch/loongarch-def.cc:186: note:
    'abi_minimal_isa' was previously declared here
    186 |   abi_minimal_isa = array<array<loongarch_isa, N_ABI_EXT_TYPES>,
    ../../gcc/config/loongarch/loongarch-def.cc:186: note:
    code may be misoptimized unless '-fno-strict-aliasing' is used

Fix it by adding a proper declaration of abi_minimal_isa into
loongarch-def.h and remove the ODR-violating local declaration in
loongarch-opts.cc.

gcc/ChangeLog:

        * config/loongarch/loongarch-def.h (abi_minimal_isa): Declare.
        * config/loongarch/loongarch-opts.cc (abi_minimal_isa): Remove
        the ODR-violating locale declaration.
---

Bootstrapped on loongarch64-linux-gnu.  Not fully regtested but it
should be an obvious fix.  Ok for trunk?

 gcc/config/loongarch/loongarch-def.h   | 3 +++
 gcc/config/loongarch/loongarch-opts.cc | 2 --
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/gcc/config/loongarch/loongarch-def.h 
b/gcc/config/loongarch/loongarch-def.h
index a1237ecf1fd..2dbf006d013 100644
--- a/gcc/config/loongarch/loongarch-def.h
+++ b/gcc/config/loongarch/loongarch-def.h
@@ -203,5 +203,8 @@ extern loongarch_def_array<loongarch_align, N_TUNE_TYPES>
   loongarch_cpu_align;
 extern loongarch_def_array<loongarch_rtx_cost_data, N_TUNE_TYPES>
   loongarch_cpu_rtx_cost_data;
+extern loongarch_def_array<
+  loongarch_def_array<loongarch_isa, N_ABI_EXT_TYPES>,
+  N_ABI_BASE_TYPES> abi_minimal_isa;
 
 #endif /* LOONGARCH_DEF_H */
diff --git a/gcc/config/loongarch/loongarch-opts.cc 
b/gcc/config/loongarch/loongarch-opts.cc
index b87299513c9..7eeac43ed2f 100644
--- a/gcc/config/loongarch/loongarch-opts.cc
+++ b/gcc/config/loongarch/loongarch-opts.cc
@@ -53,8 +53,6 @@ static const int tm_multilib_list[] = { TM_MULTILIB_LIST };
 static int enabled_abi_types[N_ABI_BASE_TYPES][N_ABI_EXT_TYPES] = { 0 };
 
 #define isa_required(ABI) (abi_minimal_isa[(ABI).base][(ABI).ext])
-extern "C" const struct loongarch_isa
-abi_minimal_isa[N_ABI_BASE_TYPES][N_ABI_EXT_TYPES];
 
 static inline int
 is_multilib_enabled (struct loongarch_abi abi)
-- 
2.43.0