[gcc r12-7461] [nvptx] Use --no-verify for sm_30

[gcc r12-7461] [nvptx] Use --no-verify for sm_30

[Tom de Vries]

https://gcc.gnu.org/g:12fa7641ceed9c9139e2ea7b62c11f3dc5b6f6f4

commit r12-7461-g12fa7641ceed9c9139e2ea7b62c11f3dc5b6f6f4
Author: Tom de Vries <tdevries@suse.de>
Date:   Thu Mar 3 09:21:04 2022 +0100

    [nvptx] Use --no-verify for sm_30
    
    In PR97348, we ran into the problem that recent CUDA dropped support for
    sm_30, which inhibited the build when building with CUDA bin in the path,
    because the nvptx-tools assembler uses CUDA's ptxas to do ptx verification.
    
    To fix this, in gcc-11 the default sm_xx was moved from sm_30 to sm_35.
    
    This however broke support for sm_30 boards: an executable build for sm_30
    might contain sm_35 code from the libraries, which are build with the default
    sm_xx (PR104758).
    
    We want to fix this by going back to having the libraries build with sm_30, as
    was the case for gcc-5 to gcc-10.  That however reintroduces the problem from
    PR97348.
    
    Deal with PR97348 in the simplest way possible: when calling the assembler for
    sm_30, specify --no-verify.
    
    This has the unfortunate effect that after fixing PR104758 by building
    libraries with sm_30, the libraries are no longer verified.  This can be
    improved upon by:
    - adding a configure test in gcc that tests if CUDA supports sm_30, and
      if so disabling this patch
    - dealing with this in nvptx-tools somehow, either:
      - detect at ptxas execution time that it doesn't support sm_30, or
      - detect this at nvptx-tool configure time.
    
    gcc/ChangeLog:
    
    2022-03-03  Tom de Vries  <tdevries@suse.de>
    
            * config/nvptx/nvptx.h (ASM_SPEC): Add %{misa=sm_30:--no-verify}.

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

diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 4ab412bc7d8..3ca22a595d2 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -32,7 +32,7 @@
 /* Default needs to be in sync with default for misa in nvptx.opt.
    We add a default here to work around a hard-coded sm_30 default in
    nvptx-as.  */
-#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
+#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}%{misa=sm_30:--no-verify}"
 
 #define TARGET_CPU_CPP_BUILTINS() nvptx_cpu_cpp_builtins ()