On Sat, Jul 13, 2024 at 9:38 AM Hanke Zhang via Gcc <gcc@gcc.gnu.org> wrote:
>
> Hi,
>
> I'm attempting to enable more flags in Ofast, but I've encountered some
> issues.
I suspect you need to handle this in the driver specs instead of in
opts.cc. Since -flto-partition=one is more of a global flag rather
than an optimization flag.
common.opt does not mark -flto-partition= as an optimization flag either.
Plus IIRC flto-partition= needs to be passed down to the linker in
this case too.
Thanks,
Andrew Pinski
>
> For instance, if I want to add -flto-partition=one to Ofast, here is
> the modification I made to opts.cc
>
> /* -Ofast adds optimizations to -O3. */
> { OPT_LEVELS_FAST, OPT_ffast_math, NULL, 1 },
> { OPT_LEVELS_FAST, OPT_fallow_store_data_races, NULL, 1 },
> { OPT_LEVELS_FAST, OPT_fsemantic_interposition, NULL, 0 },
> ++ { OPT_LEVELS_FAST, OPT_flto_partition_, NULL, LTO_PARTITION_ONE },
>
> However, when I run the tests (make -k check), I encounter some
> problems. One of the failed test files is gcc.dg/pr89342.c:
>
> /* PR other/89342 */
> /* { dg-do compile } */
> /* { dg-options "-O0" } */
>
> __attribute__((optimize("Ofast")))
> void foo (void)
> {
> __attribute__((optimize("no-inline")))
> void bar (void) {}
> bar ();
> }
>
> The error message is as follows:
>
> ../gcc/testsuite/gcc.dg/pr89342.c:7:1: internal compiler error:
> ‘global_options’ are modified in local context
> 7 | {
> | ^
> 0x9e8cf4 handle_optimize_attribute
> ../../gcc/c-family/c-attribs.cc:5568
> 0x8e0902 decl_attributes(tree_node**, tree_node*, int, tree_node*)
> ../../gcc/attribs.cc:872
> 0x8fe39c start_function(c_declspecs*, c_declarator*, tree_node*)
> ../../gcc/c/c-decl.cc:9519
> 0x962336 c_parser_declaration_or_fndef
> ../../gcc/c/c-parser.cc:2445
> 0x96b803 c_parser_external_declaration
> ../../gcc/c/c-parser.cc:1779
> 0x96c263 c_parser_translation_unit
> ../../gcc/c/c-parser.cc:1652
> 0x96c263 c_parse_file()
> ../../gcc/c/c-parser.cc:23372
> 0x9cf4a5 c_common_parse_file()
> ../../gcc/c-family/c-opts.cc:1240
>
> Upon debugging, I found that the error occurs in the
> cl_optimization_compare(gcc_options *ptr1, gcc_options *ptr2) function
> in options-save.cc. Specifically, the discrepancy is here:
>
> ptr1->x_flag_lto_partition: 2, ptr2->x_flag_lto_partition: 1
>
> This discrepancy leads to the error. Could you advise on how to
> resolve this issue?
>
> (Note: My ultimate goal is not to add the -flto-partition=one flag.
> This is just an example to illustrate the problem.)
>
> Thank you for your assistance.
>
> Thanks
> Hanke Zhang
