>
> On 2/23/21 3:14 AM, YunQiang Su wrote:
> > For MIPSr6, we may wish to use compact-branches only.
> > Currently, we have to use `always' option, while it is mark as
> > conflict with pre-R6.
> > cc1: error: unsupported combination: ‘mips32r2’
> > -mcompact-branches=always Just ignore -mcompact-branches=always for
> pre-R6.
> >
> > This patch also defines
> > __mips_compact_branches_never
> > __mips_compact_branches_always
> > __mips_compact_branches_optimal
> > predefined macros
> >
> > gcc/ChangeLog:
> > * config/mips/mips.c (mips_option_override):
> > * config/mips/mips.h (TARGET_RTP_PIC): not trigger error for
> > compact-branches=always for pre-R6.
> > (TARGET_CB_NEVER): Likewise.
> > (TARGET_CB_ALWAYS): Likewise.
> > (struct mips_cpu_info): define macros for compact branch policy.
> > * doc/invoke.texi: Document "always" with pre-R6.
> >
> > gcc/testsuite/ChangeLog:
> > * gcc.target/mips/compact-branches-1.c: add isa_rev>=6.
> > * gcc.target/mips/mips.exp: don't add -mipsXXr6 option for
> > -mcompact-branches=always. It is usable for pre-R6 now.
> > * gcc.target/mips/compact-branches-8.c: New test.
> > * gcc.target/mips/compact-branches-9.c: New test.
> So I think Maciej's comment was that you simply shouldn't be using
> -mcompact-branches=always at mips32r2 (or anything pre-r6) together.
>
> I think what you're trying to do here is set up a scenario where you're
> defaulting to mips32r6 and compact-branches, but not error if something
> specifies -mcpu=mips32r2 or something similar, right?
>
Yes. If we introduce the build time option, and configure gcc with always, then
gcc will always try to
Pass -mconpact-branches=always to cc1, even we use something like:
mipsisa32r6el-linux-gnu-gcc -mips32r2 -c xx.c
It may break something.
> jeff
