[Bug target/51552] New: bfin generates bad assembly

[Bug target/51552] New: bfin generates bad assembly

[joel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51552

             Bug #: 51552
           Summary: bfin generates bad assembly
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: joel@gcc.gnu.org


Created attachment 26085
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26085
Preprocessed test case

xgcc (GCC) 4.7.0 20111214 (experimental) [trunk revision 182330]
Target: bfin-rtems4.11 compiling newlib

/home2/joel/build/b-bfin-gcc/./gcc/xgcc -B/home2/joel/build/b-bfin-gcc/./gcc/
-nostdinc -B/home2/joel/build/b-bfin-gcc/bfin-rtems4.11/newlib/ -isystem
/home2/joel/build/b-bfin-gcc/bfin-rtems4.11/newlib/targ-include -isystem
/users/joel/test-gcc/gcc-svn/newlib/libc/include
-B/users/joel/test-gcc/install-svn/bfin-rtems4.11/bin/
-B/users/joel/test-gcc/install-svn/bfin-rtems4.11/lib/ -isystem
/users/joel/test-gcc/install-svn/bfin-rtems4.11/include -isystem
/users/joel/test-gcc/install-svn/bfin-rtems4.11/sys-include   
-DPACKAGE_NAME=\"newlib\" -DPACKAGE_TARNAME=\"newlib\"
-DPACKAGE_VERSION=\"1.19.0\" -DPACKAGE_STRING=\"newlib\ 1.19.0\"
-DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -I.
-I/users/joel/test-gcc/gcc-svn/newlib/libc/string -D_COMPILING_NEWLIB
-DMALLOC_PROVIDED -DEXIT_PROVIDED -DSIGNAL_PROVIDED
-DREENTRANT_SYSCALLS_PROVIDED -DHAVE_NANOSLEEP -DHAVE_BLKSIZE -DHAVE_FCNTL
-DHAVE_ASSERT_FUNC -D_NO_GETLOGIN -D_NO_GETPWENT -D_NO_GETUT -D_NO_GETPASS
-D_NO_SIGSET -D_NO_WORDEXP -D_NO_POPEN -Wall -fno-builtin      -g -O2 -c -o
lib_a-strsignal.o `test -f 'strsignal.c' || echo
'/users/joel/test-gcc/gcc-svn/newlib/libc/string/'`strsignal.c
/tmp/cctEZ5VY.s: Assembler messages:
/tmp/cctEZ5VY.s:24: Error: syntax error. Input text was .LCFI1.
/tmp/cctEZ5VY.s:24: Error: 

Cutting this down, it appears to be the -g flag:


[joel@rtbf64a string]$ /home2/joel/build/b-bfin-gcc/./gcc/xgcc
-B/home2/joel/build/b-bfin-gcc/./gcc/ -O2 -c -fno-builtin j.c
[joel@rtbf64a string]$ /home2/joel/build/b-bfin-gcc/./gcc/xgcc
-B/home2/joel/build/b-bfin-gcc/./gcc/ -O2 -c -g -fno-builtin j.c
/tmp/ccwaXpNe.s: Assembler messages:
/tmp/ccwaXpNe.s:24: Error: syntax error. Input text was .LCFI1.
/tmp/ccwaXpNe.s:24: Error: 

The bad asm generated is here:

.LCFI0:
        R2 = ROT R0 BY 0 ||
.LCFI1:
        R7 = [P2] ||
        nop;

I am guessing there should have been a semi-colon and maybe a nop before
.LCFI1.

[Bug target/51552] bfin generates bad assembly

[jiez at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51552

Jie Zhang <jiez at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011-12-17
                 CC|                            |jiez at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #1 from Jie Zhang <jiez at gcc dot gnu.org> 2011-12-17 03:06:37 UTC ---
This was caused by r177218 for PR target/49864.

[Bug target/51552] bfin generates bad assembly

[jiez at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51552

--- Comment #2 from Jie Zhang <jiez at gcc dot gnu.org> 2011-12-21 04:35:19 UTC ---
(gdb) p insn
$23 = (rtx) 0x7ffff701b180
(gdb) pr
(parallel [
        (unspec [
                (const_int -4 [0xfffffffffffffffc])
            ] 5)
        (set/f (mem:SI (plus:SI (reg/f:SI 14 SP)
                    (const_int -4 [0xfffffffffffffffc])) [0 S4 A32])
            (reg:SI 7 R7))
        (set/f (reg/f:SI 14 SP)
            (plus:SI (reg/f:SI 14 SP)
                (const_int -4 [0xfffffffffffffffc])))

Before that commit, dwarf2out_frame_debug_expr (insn) will set any_cfis_emitted
in dwarf2out_frame_debug, which will cause dwarf2out_flush_queued_reg_saves to
emit the CFI. But after that commit, dwarf2out_frame_debug_expr (insn) will not
set any_cfis_emitted.

[Bug target/51552] bfin generates bad assembly

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51552

Richard Henderson <rth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rth at gcc dot gnu.org

--- Comment #3 from Richard Henderson <rth at gcc dot gnu.org> 2011-12-21 17:51:30 UTC ---
Well, honestly the largest problem is that the bfin backend is
emitting bundles in a way that can't be split, but in separate insns.

The ia64 backend handles this case by supporting "debug labels"
in the assembler, which are understood not to break the bundle.

As far as the middle-end is concerned, it's doing absolutely nothing
wrong. I'll see what I can do to restore the kinda-sorta working state
that we had before, but you really ought to fix the backend to not
lie to the middle-end.

Consider implementing debug labels in the assembler.  Or failing
that, pack your insn bundles into sequences, or something.

[Bug target/51552] bfin generates bad assembly

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51552

Richard Henderson <rth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |rth at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #4 from Richard Henderson <rth at gcc dot gnu.org> 2011-12-21 18:12:39 UTC ---
Mine.  The only thing I'll concede is that this is a debug size
regression from 4.6, as there's an unnecessary advance between
the two cfi opcodes.

[Bug target/51552] bfin generates bad assembly

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51552

--- Comment #5 from Richard Henderson <rth at gcc dot gnu.org> 2011-12-21 20:21:14 UTC ---
Author: rth
Date: Wed Dec 21 20:21:00 2011
New Revision: 182604

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=182604
Log:
PR target/51552
        * dwarf2cfi.c (dwarf2out_frame_debug): Move any_cfis_emitted code...
        (scan_trace): ... here.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/dwarf2cfi.c

[Bug target/51552] bfin generates bad assembly

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51552

Richard Henderson <rth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #6 from Richard Henderson <rth at gcc dot gnu.org> 2011-12-21 20:35:52 UTC ---
http://gcc.gnu.org/ml/gcc-patches/2011-12/msg01577.html