[gcc(refs/vendors/riscv/heads/gcc-14-with-riscv-opts)] RISC-V: Lookup reversely in riscv_select_multilib_by_abi

[Jeff Law via Gcc-cvs]

https://gcc.gnu.org/g:e3dcc815e3d72d6e63503e6c72a70576c5108a6a

commit e3dcc815e3d72d6e63503e6c72a70576c5108a6a
Author: YunQiang Su <yunqi...@isrc.iscas.ac.cn>
Date:   Thu Sep 5 15:14:43 2024 +0800

    RISC-V: Lookup reversely in riscv_select_multilib_by_abi
    
    When use --print-multi-os-dir or -print-multi-directory, gcc outputs
    different values with full -march option and the base one only.
    
    $ ./gcc/xgcc --print-multi-os-dir -mabi=lp64d -march=rv64gc
    lib64/lp64d
    
    $ ./gcc/xgcc --print-multi-os-dir -mabi=lp64d -march=rv64gc_zba
    .
    
    The reason is that in multilib.h, the fallback value of multilib
    is listed as the 1st one in `multilib_raw[]`.
    
    gcc
            * common/config/riscv/riscv-common.cc(riscv_select_multilib_by_abi):
            look up reversely as the fallback path is listed as the 1st one.
    
    (cherry picked from commit 3162abfb5098934e6ed9d4307a86a84d28823612)

Diff:
---
 gcc/common/config/riscv/riscv-common.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/common/config/riscv/riscv-common.cc 
b/gcc/common/config/riscv/riscv-common.cc
index 62c6e1dab1f..2c1ce7fc7cb 100644
--- a/gcc/common/config/riscv/riscv-common.cc
+++ b/gcc/common/config/riscv/riscv-common.cc
@@ -2079,7 +2079,7 @@ riscv_select_multilib_by_abi (
   const std::string &riscv_current_abi_str,
   const std::vector<riscv_multi_lib_info_t> &multilib_infos)
 {
-  for (size_t i = 0; i < multilib_infos.size (); ++i)
+  for (ssize_t i = multilib_infos.size (); i >= 0; --i)
     if (riscv_current_abi_str == multilib_infos[i].abi_str)
       return xstrdup (multilib_infos[i].path.c_str ());