[Bug target/36135] GCC creates suboptimal ASM : suboptimal Adressing-Modes used

["gunnar at greyhound-data dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #3 from gunnar at greyhound-data dot com  2008-06-12 14:34 -------
Andreas,

What is your opinion to this?

GCC 2.9 used to combine the move with increment in the combine step to
something like this:
***
(insn 32 30 33 (set (reg/v:SI 32)
        (mem:SI (post_inc:SI (reg/v:SI 34)) 0)) 42 {movsi+1} (nil)
    (expr_list:REG_INC (reg/v:SI 34)
        (nil)))
***


So problem is that now GCC seems not to be able to do this anymore by itself
With GCC 4.4 the output is:
**
(insn 34 33 35 4 example2.c:11 (set (reg/v:SI 54 [ value ])
        (mem:SI (reg/v/f:SI 52 [ src ]) [2 S4 A16])) 37 {*movsi_cf} (nil))

(insn 35 34 36 4 example2.c:12 (set (reg/v:SI 53 [ value2 ])
        (mem:SI (plus:SI (reg/v/f:SI 52 [ src ])
                (const_int 4 [0x4])) [2 S4 A16])) 37 {*movsi_cf} (nil))

(insn 36 35 38 4 example2.c:5 (set (reg/v/f:SI 52 [ src ])
        (plus:SI (reg/v/f:SI 52 [ src ])
            (const_int 8 [0x8]))) 133 {*addsi3_5200} (nil))

(insn 38 36 40 4 example2.c:10 (set (reg/v:SI 50 [ size.21 ])
        (plus:SI (reg/v:SI 50 [ size.21 ])
            (const_int -1 [0xffffffff]))) 133 {*addsi3_5200} (nil))
***

Any ideas about this?


Kind regards

Gunnar von Boehn


-- 

gunnar at greyhound-data dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |schwab at suse dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36135