http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52306
--- Comment #15 from Mikael Pettersson <mikpe at it dot uu.se> 2013-01-30
17:34:11 UTC ---
(In reply to comment #1)
> The bug, duplicated by compiling attachment 26150 [details], from bug 43437
> comment 16,
> with a cross-compiler to m68k-elf with -O -c, exposes a reload problem.
> Before
> reload, we have this insn:
>
> (insn 288 287 290 40 (set (reg/f:SI 124 [ D.1788 ])
> (mem/f:SI (post_inc:SI (reg:SI 145 [ ivtmp.76 ])) [5 MEM[base:
> D.1889_285, offset: 0B]+0 S4 A16])) pr52306.c:278 37 {*movsi_m68k2}
> (expr_list:REG_INC (reg:SI 145 [ ivtmp.76 ])
> (nil)))
But isn't this already invalid, as it has both a post_inc and a REG_INC of the
same (reg:SI 145 [ ivtmp.76 ]) operand?
This is produced by the auto_inc_dec pass. Before that we have (175r.fwprop2):
(insn 188 187 190 22 (set (reg/v:SI 76 [ i ])
(plus:SI (reg/v:SI 76 [ i ])
(const_int 1 [0x1]))) pr43437-2.c:222 132 {*addsi3_internal}
(nil))
(insn 190 188 191 22 (set (cc0)
(compare (reg/v:SI 76 [ i ])
(reg/v:SI 68 [ n ]))) pr43437-2.c:222 14 {*m68k.md:486}
(nil))
which auto_inc_dec turns into (176r.auto_inc_dec):
289 r145:SI=r145:SI+0x4
288 r124:SI=[r145:SI]
288 r124:SI=[r145:SI]
found mem(288) *(r[145]+0)
289 r145:SI=r145:SI+0x4
found post inc(289) r[145]+=4
trying SIMPLE_POST_INC
rescanning insn with uid = 288.
deleting insn with uid = 288.
deleting insn with uid = 289.
****success 288 r124:SI=[r145:SI++]
REG_INC: r145:SI
...
288 r124:SI=[r145:SI++]
REG_INC: r145:SI
...
(insn 288 287 290 41 (set (reg/f:SI 124 [ D.1812 ])
(mem/f:SI (post_inc:SI (reg:SI 145 [ ivtmp.80 ])) [5 MEM[base:
D.1914_291, offset: 0B]+0 S4 A16])) pr43437-2.c:278 37 {*movsi_m68k2}
(expr_list:REG_INC (reg:SI 145 [ ivtmp.80 ])
(nil)))
Is this valid?
