------- Comment #2 from ubizjak at gmail dot com 2007-06-11 07:35 -------
This is the fault of combine pass. It isn't obvious to me, why it is
converting:
(insn 7 6 13 2 shift.c:6 (set (subreg:TI (reg:V2DI 62) 0)
(ashift:TI (subreg:TI (reg:V2DI 61 [ __a ]) 0)
(const_int 64 [0x40]))) 1115 {sse2_ashlti3} (insn_list:REG_DEP_TRUE
6 (nil))
(expr_list:REG_DEAD (reg:V2DI 61 [ __a ])
(expr_list:REG_EQUAL (ashift:TI (subreg:TI (reg/v:V2DI 60 [ __a ]) 0)
(const_int 64 [0x40]))
(nil))))
)
to
(insn 7 6 13 2 shift.c:6 (parallel [
(set (subreg:TI (reg:V2DI 62) 0)
(ashift:TI (reg:TI 21 xmm0 [ __a ])
(const_int 64 [0x40])))
(clobber (reg:CC 17 flags))
]) 412 {*ashlti3_2} (nil)
(expr_list:REG_UNUSED (reg:CC 17 flags)
(expr_list:REG_DEAD (reg:V2DI 21 xmm0 [ __a ])
(nil))))
Note the clobber in above pattern. So, what is wrong with:
(define_insn "sse2_ashlti3"
[(set (match_operand:TI 0 "register_operand" "=x")
(ashift:TI (match_operand:TI 1 "register_operand" "0")
(match_operand:SI 2 "const_0_to_255_mul_8_operand" "n")))]
"TARGET_SSE2"
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32280
