[df] RFA: artifical defs of global registers for EH, etc.

[Richard Sandiford]

Ian Lance Taylor <iant@google.com> writes:
> Richard Sandiford <rsandifo@nildram.co.uk> writes:
>
>> gcc/
>> 	* df-scan.c (df_bb_refs_collect): Only compute bb_has_eh_pred once.
>> 	Create artificial definitions of global registers at the beginning
>> 	of non-local goto receivers and exception handlers.
>> 	(df_get_entry_block_def_set): Add global registers.
>
> If you or somebody else can construct a test case for which this
> generates incorrect code, then this is OK for mainline, ideally with
> that test case committed as well.  It seems to me that it should be
> possible to construct a target specific test case involving a global
> register and a non-local goto.

Thanks.  I've tried to come up with a testcase, but haven't
managed to.  Let's leave it till 4.4.

Richard