[Bug rtl-optimization/24265] New: ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[Bug rtl-optimization/24265] New: ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[ferdinandw+gcc at gmail dot com]

/tmp/gcc41/libexec/gcc/i686-pc-linux-gnu/4.1.0/cc1 -quiet -v test.c -dumpbase
test.c -mtune=pentiumpro -auxbase-strip test.o -O -version
-fmove-loop-invariants -fgcse -o test.o

GNU C version 4.1.0 20051007 (experimental) (i686-pc-linux-gnu)
        compiled by GNU C version 4.1.0 20051007 (experimental).
GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=129306
Compiler executable checksum: a278381769db4d67bad1ec630ceb45dd
test.c: In function 'foo':
test.c:14: error: unrecognizable insn:
(insn 21 16 39 0 (set (reg:DF 64)
        (const_double:DF -858993460 [0xcccccccc]
2.00000000000000011102230246251565404236316680908e-1 [0x0.ccccccccccccdp-2]))
-1 (nil)
    (nil))
test.c:14: internal compiler error: in extract_insn, at recog.c:2084

Configured with: ../gcc/configure --prefix=/tmp/gcc41 --enable-languages=c
--disable-nls --enable-checking=assert,rtlflag,misc

========================================================

void dset (double d1, double d2);

void foo ()
{
  int i;
  double m, d = 0.2;

  dset (m,d);

  for (i=1; i<=3; i++) {
    dset (m,d);
  }

}

========================================================

d needs to have the same value in both calls to dset for this ICE to occur.


-- 
           Summary: ICE: in extract_insn, at recog.c:2084 with -O -fgcse -
                    fmove-loop-invariants -mtune=pentiumpro
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ferdinandw+gcc at gmail dot com
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2005-10-07 19:58 -------
Confirmed, a regression from 4.0.0.

I think this is a target bug as you had:
(set (mem:DF (plus:SI (reg/f:SI 7 sp)
                 (const_int 8 [0x8])) [0 S8 A32])
        (const_double:DF -858993460 [0xcccccccc]
2.00000000000000011102230246251565404236316680908e-1 [0x0.ccccccccccccdp-2]))

before loop-invariant but after, you have:
(insn 21 16 17 0 (set (reg:DF 64)
+        (const_double:DF -858993460 [0xcccccccc]
2.00000000000000011102230246251565404236316680908e-1 [0x0.ccccccccccccdp-2]))
-1 (nil)
+    (nil))

Unless -fmove-loop-invariants is not calling emit_move_insn which might be the
issue.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
          Component|rtl-optimization            |target
     Ever Confirmed|0                           |1
           Keywords|                            |ice-on-valid-code
      Known to fail|                            |4.1.0
      Known to work|                            |4.0.0
   Last reconfirmed|0000-00-00 00:00:00         |2005-10-07 19:58:56
               date|                            |
            Summary|ICE: in extract_insn, at    |[4.1 Regression] ICE: in
                   |recog.c:2084 with -O -fgcse |extract_insn, at
                   |-fmove-loop-invariants -    |recog.c:2084 with -O -fgcse
                   |mtune=pentiumpro            |-fmove-loop-invariants -
                   |                            |mtune=pentiumpro
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[janis at gcc dot gnu dot org]

------- Comment #2 from janis at gcc dot gnu dot org  2005-10-08 00:03 -------
A regression hunt using an i686-linux cross compiler identified this patch
from hagog@gcc.gnu.org:

  http://gcc.gnu.org/ml/gcc-cvs/2005-06/msg00015.html


-- 

janis at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hagog at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[steven at gcc dot gnu dot org]

------- Comment #3 from steven at gcc dot gnu dot org  2005-10-17 18:54 -------
The patch identified in comment #2 has nothing to do with this problem.  Pinski
is right in comment #1, loop-invariant.c does not verify that the insns it
moves/inserts are valid.  Using emit_move_insn is just one thing it should do. 
Another thing is verifying that a reg-reg move exists for expressions moved out
of a loop into a register before the loop.  There are a few other issues I
found some time ago, but I don't recall the details.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[mmitchel at gcc dot gnu dot org]

------- Comment #4 from mmitchel at gcc dot gnu dot org  2005-10-31 06:07 -------
Does the analysis in Comment #3 imply that -fmove-loop-invariants is really not
ready for use by the general public?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[hubicka at gcc dot gnu dot org]

------- Comment #5 from hubicka at gcc dot gnu dot org  2005-11-03 19:38 -------
This is ineed move-loop-invariants bug.  It assumes that destination of memory
store can be changed to register without validating
that is not the case on i386 - you can write arbitrary floating point value to
memory, but you can load only 0 and 1 to register by single direct move.


-- 

hubicka at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rakdver at gcc dot gnu dot
                   |                            |org, hubicka at gcc dot gnu
                   |                            |dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[steven at gcc dot gnu dot org]

------- Comment #6 from steven at gcc dot gnu dot org  2005-11-06 01:20 -------
Oh well, I'll try and fix this...


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |steven at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[uros at kss-loka dot si]

------- Comment #7 from uros at kss-loka dot si  2005-11-08 12:40 -------
Created an attachment (id=10173)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10173&action=view)
Patch to fix the ice

This patch fixes the failure for me, but...


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[uros at kss-loka dot si]

------- Comment #8 from uros at kss-loka dot si  2005-11-08 12:53 -------
> This patch fixes the failure for me, but...

... we actually gain nothing here.

>From .loop2_done, we have following sequence, where mem->reg load is pushed out
of the loop:

(insn 21 16 39 0 (set (reg:DF 64)
        (mem/u/c/i:DF (symbol_ref/u:SI ("*.LC0") [flags 0x2]) [0 S8 A64])) -1
(nil)
    (nil))
;; End of basic block 0, registers live:
 (nil)

(note 39 21 17 NOTE_INSN_LOOP_BEG)

;; Start of basic block 1, registers live: (nil)
(code_label 17 39 18 1 2 "" [1 uses])

(note 18 17 47 1 [bb 1] NOTE_INSN_BASIC_BLOCK)

(insn 47 18 22 1 (set (mem:DF (plus:SI (reg/f:SI 7 sp)
                (const_int 8 [0x8])) [0 S8 A32])
        (reg:DF 64)) -1 (nil)
    (nil))


However, in .postreload, the insn 21 (now insn 53) is moved back _into_ the
loop (why?):

(note 21 16 39 0 NOTE_INSN_DELETED)
;; End of basic block 0, registers live:
 6 [bp] 7 [sp] 16 [argp] 20 [frame] 60 64

(note 39 21 17 NOTE_INSN_LOOP_BEG)

;; Start of basic block 1, registers live: 6 [bp] 7 [sp] 59 60 64
(code_label 17 39 18 1 2 "" [1 uses])

(note 18 17 53 1 [bb 1] NOTE_INSN_BASIC_BLOCK)

(insn 53 18 47 1 (set (reg:DF 8 st)
        (mem/u/c/i:DF (symbol_ref/u:SI ("*.LC0") [flags 0x2]) [0 S8 A64])) 63
{*movdf_noin
teger} (nil)
    (nil))

(insn 47 53 54 1 (set (mem:DF (plus:SI (reg/f:SI 7 sp)
                (const_int 8 [0x8])) [0 S8 A32])
        (reg:DF 8 st)) 63 {*movdf_nointeger} (nil)
    (nil))


Proposed patch thus only fixes the damage. Otherwise, all this register
moving/copying doesn't gain anything, as reload fixes something on its own.

Also, REG_EQUAL notes are lost (before and after the patch). This results in
following asm:

        ...
        movl $-1717986918, 8(%esp)
        movl $1070176665, 12(%esp)
        fldl -16(%ebp)
        fstpl   (%esp)
        call dset
        movl $1, %ebx
.L2:
        fldl .LC0          <<< reload moves this insn back into the loop
        fstpl   8(%esp)
        fldl -16(%ebp)
        fstpl   (%esp)
        call dset
        incl %ebx
        cmpl $4, %ebx
        jne  .L2
        addl $36, %esp
        ...



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[uros at kss-loka dot si]

------- Comment #9 from uros at kss-loka dot si  2005-11-08 13:23 -------
Bah... set_unique_reg_note is needed:

  /* If new move insn is invalid (i.e. move of const_double to
     387 stack register), force constant into memory.  */
  if (recog_memoized (inv->insn) == -1)
    {
      rtx src = SET_SRC (set);

      if (GET_CODE (src) == CONST_DOUBLE)
        {
          SET_SRC (set) = validize_mem (force_const_mem (mode, src));
          set_unique_reg_note (inv->insn, REG_EQUAL, src);
        }
    }

to produce:

        movl $1, %ebx
.L2:
        movl $-1717986918, 8(%esp)
        movl $1070176665, 12(%esp)
        fldl -16(%ebp)
        fstpl   (%esp)
        call dset
        addl $1, %ebx
        cmpl $4, %ebx
        jne  .L2



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[steven at gcc dot gnu dot org]

------- Comment #10 from steven at gcc dot gnu dot org  2005-11-08 13:45 -------
The patch from comment #7 is wrong.

The proper fix is already on the killloop-branch.  You could try my patch for
PR 24408, which should depend on this one.


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |24408
              nThis|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[steven at gcc dot gnu dot org]

------- Comment #11 from steven at gcc dot gnu dot org  2005-11-11 19:34 -------
Subject: Bug 24265

Author: steven
Date: Fri Nov 11 19:34:39 2005
New Revision: 106795

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=106795
Log:
        PR 24265
        * loop-invariant.c (may_assign_reg_p): Make sure a hard register
        can be assigned to.
        (find_invariant_insn): Do the cheapest check, may_assign_reg_p,
        before check_maybe_invariant.
        (move_invariant_reg): Use gen_move_insn instead of replacing
        SET_DEST with the temporary for the invariant.
        (move_loop_invariants): If checking is enabled, do internal
        consistency checks after completing the pass.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/loop-invariant.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265

[Bug target/24265] [4.1 Regression] ICE: in extract_insn, at recog.c:2084 with -O -fgcse -fmove-loop-invariants -mtune=pentiumpro

[steven at gcc dot gnu dot org]

------- Comment #12 from steven at gcc dot gnu dot org  2005-11-11 19:39 -------
Fixed on mainline.  The bug is also on the GCC 4.0 branch, but I am not going
to backport the patch.


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24265