This merges -O options given at compile-time into a single
optimization level to be used for LTO link time (but
overridden with whatever is specified at LTO link time - unless
no optimization level is specified there). That is, it
determines a "default" optimization level used at LTO link time
(as opposed to the default optimization level zero).
Currently the code merges exact same options as-is and
mismatching optimization levels based on the maximum value of
'optimize' they cause and merging it as -Ooptimize.
Thus -Og and -Os get merged as -O2, -O and -Ofast get merged as -O3
and -O and -O1 get merged as -O1.
Specifying any optimization level explicitely at link time
will override what we came up with above (including explicitely
specifying -O0).
Comments?
I've tested that it works as expected. Do we want something like
this for 4.9?
Thanks,
Richard.
2014-03-04 Richard Biener <rguent...@suse.de>
* lto-wrapper.c (merge_and_complain): Merge compile-time
optimization levels.
(run_gcc): And pass it through to the link options.
Index: gcc/lto-wrapper.c
===================================================================
*** gcc/lto-wrapper.c (revision 208305)
--- gcc/lto-wrapper.c (working copy)
*************** merge_and_complain (struct cl_decoded_op
*** 459,464 ****
--- 459,535 ----
fatal ("Option %s not used consistently in all LTO input files",
foption->orig_option_with_args_text);
break;
+
+ case OPT_O:
+ case OPT_Ofast:
+ case OPT_Og:
+ case OPT_Os:
+ for (j = 0; j < *decoded_options_count; ++j)
+ if ((*decoded_options)[j].opt_index == OPT_O
+ || (*decoded_options)[j].opt_index == OPT_Ofast
+ || (*decoded_options)[j].opt_index == OPT_Og
+ || (*decoded_options)[j].opt_index == OPT_Os)
+ break;
+ if (j == *decoded_options_count)
+ append_option (decoded_options, decoded_options_count, foption);
+ else if ((*decoded_options)[j].opt_index == foption->opt_index
+ && foption->opt_index != OPT_O)
+ /* Exact same options get merged. */
+ ;
+ else
+ {
+ /* For mismatched option kinds preserve the optimization
+ level only, thus merge it as -On. This also handles
+ merging of same optimization level -On. */
+ int level = 0;
+ switch (foption->opt_index)
+ {
+ case OPT_O:
+ if (foption->arg[0] == '\0')
+ level = MAX (level, 1);
+ else
+ level = MAX (level, atoi (foption->arg));
+ break;
+ case OPT_Ofast:
+ level = MAX (level, 3);
+ break;
+ case OPT_Og:
+ level = MAX (level, 1);
+ break;
+ case OPT_Os:
+ level = MAX (level, 2);
+ break;
+ default:
+ gcc_unreachable ();
+ }
+ switch ((*decoded_options)[j].opt_index)
+ {
+ case OPT_O:
+ if ((*decoded_options)[j].arg[0] == '\0')
+ level = MAX (level, 1);
+ else
+ level = MAX (level, atoi ((*decoded_options)[j].arg));
+ break;
+ case OPT_Ofast:
+ level = MAX (level, 3);
+ break;
+ case OPT_Og:
+ level = MAX (level, 1);
+ break;
+ case OPT_Os:
+ level = MAX (level, 2);
+ break;
+ default:
+ gcc_unreachable ();
+ }
+ (*decoded_options)[j].opt_index = OPT_O;
+ char *tem;
+ asprintf (&tem, "-O%d", level);
+ (*decoded_options)[j].arg = &tem[2];
+ (*decoded_options)[j].canonical_option[0] = tem;
+ (*decoded_options)[j].value = 1;
+ }
+ break;
}
}
}
*************** run_gcc (unsigned argc, char *argv[])
*** 610,615 ****
--- 681,690 ----
case OPT_fwrapv:
case OPT_ftrapv:
case OPT_fstrict_overflow:
+ case OPT_O:
+ case OPT_Ofast:
+ case OPT_Og:
+ case OPT_Os:
break;
default:
