[gcc r12-7463] [nvptx] Build libraries with mptx=3.1

[Tom de Vries]

https://gcc.gnu.org/g:5b5e456f0187406e17444b6e40d974f94524f2a2

commit r12-7463-g5b5e456f0187406e17444b6e40d974f94524f2a2
Author: Tom de Vries <tdevries@suse.de>
Date:   Thu Mar 3 09:22:42 2022 +0100

    [nvptx] Build libraries with mptx=3.1
    
    In gcc-5 to gcc-11, the ptx isa version was 3.1.
    
    On trunk, the default is now 6.0, which is also what will be the value in
    the libraries.
    
    Consequently, there may be setups with an older driver that worked with
    gcc-11, but will become unsupported with gcc-12.
    
    Fix this by building the libraries with mptx=3.1.
    
    After this, setups with an older driver still won't work out of the box
    with gcc-12, because the default ptx isa version has changed, but should work
    after specifying mptx=3.1.
    
    gcc/ChangeLog:
    
    2022-03-03  Tom de Vries  <tdevries@suse.de>
    
            * config/nvptx/t-nvptx (MULTILIB_EXTRA_OPTS): Add mptx=3.1.

Diff:
---
 gcc/config/nvptx/t-nvptx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/config/nvptx/t-nvptx b/gcc/config/nvptx/t-nvptx
index 056d2dd2d04..8f67264d132 100644
--- a/gcc/config/nvptx/t-nvptx
+++ b/gcc/config/nvptx/t-nvptx
@@ -32,4 +32,4 @@ s-nvptx-gen-opt: $(srcdir)/config/nvptx/nvptx-sm.def
 
 MULTILIB_OPTIONS = mgomp
 
-MULTILIB_EXTRA_OPTS = misa=sm_30
+MULTILIB_EXTRA_OPTS = misa=sm_30 mptx=3.1