Re: PATCH: PR target/59794: [4.7/4.8/4.9 Regression] i386 backend fails to detect MMX/SSE/AVX ABI changes

[Uros Bizjak <ubizjak at gmail dot com>]

On Tue, Jan 14, 2014 at 3:18 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:

> There are several problems with i386 MMX/SSE/AVX ABI change detection:
>
> 1. MMX/SSE return value isn't checked for -m32 since revision 83533:
>
> http://gcc.gnu.org/viewcvs/gcc?view=revision&revision=83533
>
> which added ix86_struct_value_rtx.  Since MMX/SSE condition is always
> false, the MMX/SSE return value ABI change is disabled.
> 2. For -m32, the same warning on MMX/SSE argument is issued twice, one from
> type_natural_mode and one from function_arg_32.
> 3. AVX return value ABI change isn't checked.
>
> This patch does followings:
>
> 1. Remove the ineffective ix86_struct_value_rtx.
> 2. Add a bool parameter to indicate if type is used for function return
> value.  Warn ABI change if the vector mode isn't available for function
> return value.  Add AVX function return value ABI change warning.
> 3. Consolidate ABI change warning into type_natural_mode.
> 4. Update g++.dg/ext/vector23.C to prune ABI change for Linux/x86
> added by the AVX function return value ABI change warning.
> 5. Update gcc.target/i386/pr39162.c to avoid the AVX function return
> value ABI change warning.
> 6. Add testcases for warning MMX/SSE/AVX ABI changes in parameter
> passing and function return.
>
> Tested on Linux/x86-64 with -m32/-m64 for "make check".  OK to install?
>
> Thanks.
>
> H.J.
> ---
> gcc/
>
> 2014-01-14  H.J. Lu  <hongjiu.lu@intel.com>
>
>         PR target/59794
>         * config/i386/i386.c (type_natural_mode): Add a bool parameter
>         to indicate if type is used for function return value.  Warn
>         ABI change if the vector mode isn't available for function
>         return value.
>         (ix86_function_arg_advance): Pass false to type_natural_mode.
>         (ix86_function_arg): Likewise.
>         (ix86_gimplify_va_arg): Likewise.
>         (function_arg_32): Don't warn ABI change.
>         (ix86_function_value): Pass true to type_natural_mode.
>         (ix86_return_in_memory): Likewise.
>         (ix86_struct_value_rtx): Removed.
>         (TARGET_STRUCT_VALUE_RTX): Likewise.
>
> gcc/testsuite/
>
> 2014-01-14  H.J. Lu  <hongjiu.lu@intel.com>
>
>         PR target/59794
>         * g++.dg/ext/vector23.C: Also prune ABI change for Linux/x86.
>         * gcc.target/i386/pr39162.c (y): New __m256i variable.
>         (bar): Change return type to void.  Set y to x.
>         * gcc.target/i386/pr59794-1.c: New testcase.
>         * gcc.target/i386/pr59794-2.c: Likewise.
>         * gcc.target/i386/pr59794-3.c: Likewise.
>         * gcc.target/i386/pr59794-4.c: Likewise.
>         * gcc.target/i386/pr59794-5.c: Likewise.
>         * gcc.target/i386/pr59794-6.c: Likewise.
>         * gcc.target/i386/pr59794-7.c: Likewise.

OK for mainline and release branches after a couple of days.

Thanks,
Uros.