Re: Question on fixup_abnormal_edges

[Olivier Hainque <hainque at ACT-Europe dot FR>]

Jan Hubicka wrote:
> > 
> > 
> > Jan Hubicka wrote:
> > > I think we should make reload to recognize that given insn never
> > > fallsthru and avoid it from generating such dead code.  Even in case of
> > > USE it is wrong and here as well.  What is the last insn in the basic
> > > block?
> > 
> > The same as the previous one:
> > 
> > Breakpoint 2, fixup_abnormal_edges () at ../../src/gcc/reload1.c:9522
> > 9522    && insn != bb->head)
> > 
> > (gdb) list
> > 
> > 9518    /* Get past the new insns generated. Allow notes, as the insns may
> > 9519       be already deleted.  */
> > 9520    while ((GET_CODE (insn) == INSN || GET_CODE (insn) == NOTE)
> > 9521           && !can_throw_internal (insn)
> > 9522           && insn != bb->head)
> > 9523      insn = PREV_INSN (insn);
> > 9524    if (GET_CODE (insn) != CALL_INSN && !can_throw_internal (insn))
> > 9525      abort ();
> > 9526    bb->end = insn;
> > 
> > (gdb) p e
> > $1 = 0x0
> > 
> > (gdb) pr bb->end
> > (insn 2134 444 445 (set (reg:DI 22 $22)
> >         (mem:DI (plus:DI (reg/f:DI 29 $29)
> >       (const_int 640 [0x280])) [48 S8 A64])) 244 {*movdi_nofix} (nil)
> >     (nil))
> 
> Can you print the whole BB using debug_bb?  This still looks like
> reloading, so the instruction requiring the reload is probably earlier.

Sure:

(gdb) call debug_bb (bb)

;; Basic block 50, loop depth 0, count 0
;; Predecessors:  49 [50.0%]  (fallthru)
;; Registers live at start: 26 [$26] 29 [$29] 30 [$30] 155 347
(note 1464 437 2045 [bb 50] NOTE_INSN_BASIC_BLOCK)
(note 2045 1464 441 0x40539c00 NOTE_INSN_BLOCK_END)
(insn 441 2045 443 (set (reg:DI 16 $16)
        (reg:DI 2 $2 [155])) 244 {*movdi_nofix} (nil)
    (nil))
(insn 443 441 2133 (set (reg:DI 25 $25)
        (const_int 1 [0x1])) 244 {*movdi_nofix} (insn_list:REG_DEP_ANTI 441 (nil))
    (expr_list:REG_EQUAL (const_int 1 [0x1])
        (nil)))
(insn 2133 443 444 (set (mem:DI (plus:DI (reg/f:DI 29 $29)
                (const_int 640 [0x280])) [48 S8 A64])
        (reg:DI 22 $22)) 244 {*movdi_nofix} (nil)
    (nil))
(call_insn 444 2133 2134 (parallel[ 
            (call (mem:DI (symbol_ref:DI ("ada__exceptions__reraise_occurrence_no_defer")) [0 S8 A64])
                (const_int 1 [0x1]))
            (use (const_int 0 [0x0]))
            (use (reg:DI 25 $25))
            (use (reg:DI 26 $26))
            (clobber (reg:DI 27 $27))
        ] ) 211 {*call_vms_1} (insn_list 443 (insn_list 441 (nil)))
    (expr_list:REG_EH_REGION (const_int 16 [0x10])
        (expr_list:REG_NORETURN (const_int 0 [0x0])
            (nil)))
    (expr_list (use (reg:DI 16 $16))
        (nil)))
(insn 2134 444 445 (set (reg:DI 22 $22)
        (mem:DI (plus:DI (reg/f:DI 29 $29)
                (const_int 640 [0x280])) [48 S8 A64])) 244 {*movdi_nofix} (nil)
    (nil))
;; Registers live at end: 29 [$29] 30 [$30] 31 [AP] 63 [FP] 347
;; Successors:  51 [100.0%]  (ab,abcall,eh)

> What target do you use?

alpha-dec-openvms7.1

gcc version 3.2 2002-07-26 (prerelease) + our internal GNAT tree.