mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-04-04 02:50:29 +08:00
Code Issues Packages Projects Releases Wiki Activity

rs6000.c (rs6000_override_options): Default to natural alignment for 64-bit Darwin.

Browse Source 
* config/rs6000/rs6000.c (rs6000_override_options): Default to
        natural alignment for 64-bit Darwin.
        (rs6000_parse_alignment_option): Warn about uses of -malign-power
        on 64-bit Darwin.
        * doc/invoke.texi: Document this.

From-SVN: r95420
This commit is contained in:
Stan Shebs 2005-02-22 23:38:02 +00:00 committed by Stan Shebs
parent 38f925677d
commit d9168963fa
3 changed files with 24 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
gcc/ChangeLog
View File

@ -1,3 +1,11 @@
2005-02-22 Stan Shebs <shebs@apple.com>
* config/rs6000/rs6000.c (rs6000_override_options): Default to
natural alignment for 64-bit Darwin.
(rs6000_parse_alignment_option): Warn about uses of -malign-power
on 64-bit Darwin.
* doc/invoke.texi: Document this.
2005-02-22 DJ Delorie <dj@redhat.com>
* c-common.c (c_common_type_for_mode): Pass the mode's precision

13
gcc/config/rs6000/rs6000.c
View File

@ -1316,6 +1316,8 @@ rs6000_override_options (const char *default_cpu)
#if TARGET_MACHO
darwin_one_byte_bool = "";
#endif
/* Default to natural alignment, for better performance. */
rs6000_alignment_flags = MASK_ALIGN_NATURAL;
}
/* Handle -mabi= options. */
@ -1684,7 +1686,16 @@ rs6000_parse_alignment_option (void)
if (rs6000_alignment_string == 0)
return;
else if (! strcmp (rs6000_alignment_string, "power"))
rs6000_alignment_flags = MASK_ALIGN_POWER;
{
/* On 64-bit Darwin, power alignment is ABI-incompatible with
some C library functions, so warn about it. The flag may be
useful for performance studies from time to time though, so
don't disable it entirely. */
if (DEFAULT_ABI == ABI_DARWIN && TARGET_64BIT)
warning ("-malign-power is not supported for 64-bit Darwin;"
" it is incompatible with the installed C and C++ libraries");
rs6000_alignment_flags = MASK_ALIGN_POWER;
}
else if (! strcmp (rs6000_alignment_string, "natural"))
rs6000_alignment_flags = MASK_ALIGN_NATURAL;
else

5
gcc/doc/invoke.texi
View File

@ -10528,12 +10528,15 @@ option are incompatible.
@itemx -malign-power
@opindex malign-natural
@opindex malign-power
On AIX, Darwin, and 64-bit PowerPC GNU/Linux, the option
On AIX, 32-bit Darwin, and 64-bit PowerPC GNU/Linux, the option
@option{-malign-natural} overrides the ABI-defined alignment of larger
types, such as floating-point doubles, on their natural size-based boundary.
The option @option{-malign-power} instructs GCC to follow the ABI-specified
alignment rules. GCC defaults to the standard alignment defined in the ABI@.
On 64-bit Darwin, natural alignment is the default, and @option{-malign-power}
is not supported.
@item -msoft-float
@itemx -mhard-float
@opindex msoft-float