| Message ID | 2089802.4AkFIGpqyi@polaris |
|---|---|
| State | New |
| Headers | show |
On 11/24/2016 08:30 AM, Eric Botcazou wrote: > Tests showed that it helps to eliminates redundant 32-to-64-bit extensions. > > Tested on SPARC/Solaris, applied on the mainline. > > > 2016-11-24 Eric Botcazou <ebotcazou@adacore.com> > > * common/config/sparc/sparc-common.c (option_optimization_table): > Enable REE at -O2 and higher. > * config/sparc/sparc.c (sparc_option_override): Disable it by default > in 32-bit mode. Very cool. Ideally all targets would enable REE, but we're obviously not there yet. With the fixes you've just done it's probably a lot more feasible to experiment with REE on other risc targets. jeff
> With the fixes you've just done it's probably a lot more feasible to > experiment with REE on other risc targets. I didn't experiment much, but I saw no effects at all in 32-bit mode, only in 64-bit mode. That being said, SPARC is one of the very few RISC targets that do _not_ define PROMOTE_MODE, this could be an explanation. -- Eric Botcazou
Index: common/config/sparc/sparc-common.c =================================================================== --- common/config/sparc/sparc-common.c (revision 242632) +++ common/config/sparc/sparc-common.c (working copy) @@ -28,6 +28,8 @@ along with GCC; see the file COPYING3. static const struct default_options sparc_option_optimization_table[] = { { OPT_LEVELS_1_PLUS, OPT_fomit_frame_pointer, NULL, 1 }, + /* Enable redundant extension instructions removal at -O2 and higher. */ + { OPT_LEVELS_2_PLUS, OPT_free, NULL, 1 }, { OPT_LEVELS_NONE, 0, NULL, 0 } }; Index: config/sparc/sparc.c =================================================================== --- config/sparc/sparc.c (revision 242632) +++ config/sparc/sparc.c (working copy) @@ -1713,6 +1713,11 @@ sparc_option_override (void) pessimizes for double floating-point registers. */ if (!global_options_set.x_flag_ira_share_save_slots) flag_ira_share_save_slots = 0; + + /* Only enable REE by default in 64-bit mode where it helps to eliminate + redundant 32-to-64-bit extensions. */ + if (!global_options_set.x_flag_ree && TARGET_ARCH32) + flag_ree = 0; } /* Miscellaneous utilities. */