This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Useless clobber?
- To: "Gcc at Gcc dot Gnu. Org" <gcc at gcc dot gnu dot org>
- Subject: Useless clobber?
- From: "Virgil Palanciuc" <Virgil dot Palanciuc at cs dot pub dot ro>
- Date: Tue, 11 Apr 2000 16:18:17 +0300
I found the following pattern in a .md file:
----------------------------------------------------------------------------
(define_insn ""
[(set (match_operand:SI 0 "register_operand" "=d")
(mult:SI
(zero_extend:SI
(match_operand:HI 1 "register_operand" "d"))
(zero_extend:SI
(match_operand 2 "register_operand" "d"))))
( clobber (match_operand:SI 3 "register_operand" "d"))]
""
"impyuu\\t%1,%2,%0")
----------------------------------------------------------------------------
I cannot comunicate with the guys that wrote the machine description(I
don't know how to contact them), but placing the clobber in this pattern
seems stupid to me.
On the other hand, I thought there might be a reason for this cloober to
be placed there, but I cannot think of any possible reason. Could anybody
who knows more about machine descriptions give me such a reason (or tell me
that it is safe to remove it) ?
Thanx.
Virgil