recompute opt flags after opt level change

recompute opt flags after opt level change

flag_omit_frame_pointer is set in machine-independent code depending
on the optimization level.  It is then overridden in x86
target-specific code depending on a macro defined by
--enable-frame-pointer.

Uses of attribute optimize go through machine-independent overriding
of flag_omit_frame_pointer, but the x86-specific overriding code did
NOT cover this flag, so, even if the attribute does not change the
optimization level, flag_omit_frame_pointer may end up with a
different value, and prevent inlining because of incompatible flags,
as detected by the gcc.dg/ipa/iinline-attr.c test on an
--enable-frame-pointer x86 toolchain.

for  gcc/ChangeLog

	* config/i386/i386-options.c
	(ix86_recompute_optlev_based_flags): New, moved out of...
	(ix86_option_override_internal): ... this.  Call it.
	(ix86_override_options_after_change): Call it here too.

From-SVN: r276405