Re: [PATCH] PR 15825: emit_move_insn problems in ifcvt.c (take 2)

[Roger Sayle <roger at eyesopen dot com>]

On Fri, 25 Jun 2004, Richard Henderson wrote:
> On Fri, Jun 25, 2004 at 08:49:38AM -0600, Roger Sayle wrote:
> > As a follow-up patch, I'll propose inlining seq_contains_jump
> > directly into end_ifcvt_sequence, it's only remaining caller, to
> > minimize any additional overhead with using this approach.
> > Pre-approval?
>
> Yes, merge the JUMP_INSN check into the existing insn scan loop.

Thanks.

For the record, here's the patch that I've just committed.  I only
noticed when deleting the function seq_contains_jump that the function
immediately following it, block_fallthru, didn't have a comment before
it, so I've added one.  I also took the liberty of renaming the local
variable "y" to the slightly less cryptic "insn".

The following patch has been tested on i686-pc-linux-gnu with a full
"make bootstrap", all default languages, and regression tested with a
top-level "make -k check" with no new failures.

Committed to mainline CVS.



2004-06-25  Roger Sayle  <roger@eyesopen.com>

	* ifcvt.c (seq_contains_jump): Delete function.
	(end_ifcvt_sequence): Replace call to seq_contains_jump with an
	inline test for a jump instruction in the existing "insn" loop.
	(block_fallthru): Document function.


Index: ifcvt.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/ifcvt.c,v
retrieving revision 1.148
diff -c -3 -p -r1.148 ifcvt.c
*** ifcvt.c	25 Jun 2004 18:40:05 -0000	1.148
--- ifcvt.c	25 Jun 2004 21:45:20 -0000
*************** static bool life_data_ok;
*** 88,94 ****
  static int count_bb_insns (basic_block);
  static rtx first_active_insn (basic_block);
  static rtx last_active_insn (basic_block, int);
- static int seq_contains_jump (rtx);
  static basic_block block_fallthru (basic_block);
  static int cond_exec_process_insns (ce_if_block_t *, rtx, rtx, rtx, rtx, int);
  static rtx cond_exec_get_condition (rtx);
--- 88,93 ----
*************** last_active_insn (basic_block bb, int sk
*** 213,234 ****
    return insn;
  }

! /* It is possible, especially when having dealt with multi-word
!    arithmetic, for the expanders to have emitted jumps.  Search
!    through the sequence and return TRUE if a jump exists so that
!    we can abort the conversion.  */
!
! static int
! seq_contains_jump (rtx insn)
! {
!   while (insn)
!     {
!       if (GET_CODE (insn) == JUMP_INSN)
! 	return 1;
!       insn = NEXT_INSN (insn);
!     }
!   return 0;
! }

  static basic_block
  block_fallthru (basic_block bb)
--- 212,218 ----
    return insn;
  }

! /* Return the basic block reached by falling though the basic block BB.  */

  static basic_block
  block_fallthru (basic_block bb)
*************** noce_emit_move_insn (rtx x, rtx y)
*** 707,713 ****
  static rtx
  end_ifcvt_sequence (struct noce_if_info *if_info)
  {
!   rtx y;
    rtx seq = get_insns ();

    set_used_flags (if_info->x);
--- 691,697 ----
  static rtx
  end_ifcvt_sequence (struct noce_if_info *if_info)
  {
!   rtx insn;
    rtx seq = get_insns ();

    set_used_flags (if_info->x);
*************** end_ifcvt_sequence (struct noce_if_info
*** 715,729 ****
    unshare_all_rtl_in_chain (seq);
    end_sequence ();

!   if (seq_contains_jump (seq))
!     return NULL_RTX;
!
!   /* Make sure that all of the instructions emitted are recognizable.
       As an excersise for the reader, build a general mechanism that
       allows proper placement of required clobbers.  */
!   for (y = seq; y ; y = NEXT_INSN (y))
!     if (recog_memoized (y) == -1)
        return NULL_RTX;
    return seq;
  }

--- 699,713 ----
    unshare_all_rtl_in_chain (seq);
    end_sequence ();

!   /* Make sure that all of the instructions emitted are recognizable,
!      and that we haven't introduced a new jump instruction.
       As an excersise for the reader, build a general mechanism that
       allows proper placement of required clobbers.  */
!   for (insn = seq; insn; insn = NEXT_INSN (insn))
!     if (GET_CODE (insn) == JUMP_INSN
! 	|| recog_memoized (insn) == -1)
        return NULL_RTX;
+
    return seq;
  }


Roger
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