Re: [PATCH 3/4] S390 -march=native related fixes

["Ulrich Weigand" <uweigand at de dot ibm dot com>]

Dominik Vogt wrote:

> +      opt_esa_zarch = (has_highgprs) ? " -mzarch" : " -mesa";

This will force -mesa on old machines *even in -m64 mode*,
which is wrong and will cause compilation to fail.


> -/* Defaulting rules.  */
>  #ifdef DEFAULT_TARGET_64BIT
> -#define DRIVER_SELF_SPECS					\

This completely removes use of DRIVER_SELF_SPECS for defaulting,
which I introduced back here:
https://gcc.gnu.org/ml/gcc-patches/2003-06/msg03369.html

The reason for using DRIVER_SELF_SPECS as described there is to
make sure we use compatible flags for compiler, assembler and
linker in all cases, even if some of those flags result from
defaulting rules.

If we don't do that, we rely on those components agreeing exactly
in how to default for unspecified options; for example, we want
to give the correct -march flag to the assembler as an additional
verification to detect compiler bugs where the compiler erroneously
generates an incorrect instruction for that architecture.

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  Ulrich.Weigand@de.ibm.com