2012-10-01 Michael Meissner <meiss...@linux.vnet.ibm.com>
* config/rs6000/rs6000.c (rs6000_option_override_internal): If
-mcpu=<xxx> is not specified and the compiler is not configured
using --with-cpu=<xxx>, use the bits from the TARGET_DEFAULT to
set the initial options.
I reworked the patch to allow TARGET_DEFAULT bits to be set if there is no
-mcpu=<xxx> and the compiler was not configured using --with-cpu=<xxx>, so that
we don't first clear all of the ISA bits, set them from the cpu, and then merge
back in the TARGET_DEFAULT bits.
Somebody asked about what is set, when this function gets called. The
target_flags variable is set with the initial settings (TARGET_DEFAULT) and
then all of the switches that the user sets or resets are then applied. The
target_flags_explicit variable is only set if the user explicitly used that
switch.
So for instance, if the user passed -mpopcntb -mno-vsx on Linux 64-bit systems,
target_flags would be 0x150001 (MASK_PPC_GFXOPT | MASK_POWERPC64 | MASK_64BIT |
MASK_POPCNTB) and target_flags_explicit would be 0x2010000 (MASK_POPCNTB |
MASK_VSX).
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 191942)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -2446,21 +2446,34 @@ rs6000_option_override_internal (bool gl
rs6000_cpu_index = cpu_index = main_target_opt->x_rs6000_cpu_index;
have_cpu = true;
}
+ else if (implicit_cpu)
+ {
+ rs6000_cpu_index = cpu_index = rs6000_cpu_name_lookup (implicit_cpu);
+ have_cpu = true;
+ }
else
{
- const char *default_cpu =
- (implicit_cpu ? implicit_cpu
- : (TARGET_POWERPC64 ? "powerpc64" : "powerpc"));
-
+ const char *default_cpu = (TARGET_POWERPC64 ? "powerpc64" : "powerpc");
rs6000_cpu_index = cpu_index = rs6000_cpu_name_lookup (default_cpu);
- have_cpu = implicit_cpu != 0;
+ have_cpu = false;
}
gcc_assert (cpu_index >= 0);
- target_flags &= ~set_masks;
- target_flags |= (processor_target_table[cpu_index].target_enable
- & set_masks);
+ /* If we have a cpu, either through an explicit -mcpu=<xxx> or if the
+ compiler was configured with --with-cpu=<xxx>, replace all of the ISA bits
+ with those from the cpu, except for options that were explicitly set. If
+ we don't have a cpu, do not override the target bits set in
+ TARGET_DEFAULT. */
+ if (have_cpu)
+ {
+ target_flags &= ~set_masks;
+ target_flags |= (processor_target_table[cpu_index].target_enable
+ & set_masks);
+ }
+ else
+ target_flags |= (processor_target_table[cpu_index].target_enable
+ & ~target_flags_explicit);
if (rs6000_tune_index >= 0)
tune_index = rs6000_tune_index;
--
Michael Meissner, IBM
5 Technology Place Drive, M/S 2757, Westford, MA 01886-3141, USA
meiss...@linux.vnet.ibm.com fax +1 (978) 399-6899
