On 11/26/14 14:59, Segher Boessenkool wrote:
On Wed, Nov 26, 2014 at 11:14:36AM -0700, Jeff Law wrote:
Are you talking about create_log_links? There can be no duplicates there
(anymore), that would be multiple defs of the same reg in the same insn,
indeed.
Yes, I was referring to the code in create_log_links. You dropped the
check for duplicate links. It caught my eye when reading the changes,
but then I realized the check may no longer be necessary.
Hmm, what about an insn that has two destinations, which happen to be
upper and lower SUBREGs of a pseudo. Would that create duplicate links
after your change?
Yes it would. And I'm not so certain distribute_log_links handles that
situation gracefully. Rats.
IMNSHO such RTL should be invalid (it can always be written simpler as
one SET); but there seems to be no such rule.
There's no such rule. And I was just using an example off the top of my
head. There may be others that can't necessarily be expressed by a
single set.
Jeff
