optimization/4432: ICE when using -march=k6 -O2

[reichelt@igpm.rwth-aachen.de]

>Number:         4432
>Category:       optimization
>Synopsis:       ICE when using -march=k6 -O2
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-legal-code
>Submitter-Id:   net
>Arrival-Date:   Mon Oct 01 02:36:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Volker Reichelt
>Release:        gcc 3.0.1 and 3.0.2 20010924 (prerelease)
>Organization:
>Environment:
i686-pc-linux-gnu
>Description:
Compiling the following lines of code with -march=k6 -O2
using gcc version 3.0.2 20010924 (prerelease) will crash
the compiler:

int i, *p;

int f()
{
  i;
  *p = !i;
}

I get the following error message:

bug.c: In function `f':
bug.c:7: Unrecognizable insn:
(insn 36 18 25 (parallel[ 
            (set (reg:SI 1 edx [45])
                (const_int 0 [0x0]))
            (clobber (reg:CC 17 flags))
        ] ) -1 (nil)
    (expr_list:REG_UNUSED (reg:CC 17 flags)
        (nil)))
bug.c:7: Internal compiler error in insn_default_length, at insn-attrtab.c:223
Please submit a full bug report, etc.

Remarks:
* I distilled this example from Gábor Lénárt's bug report
  ( http://gcc.gnu.org/ml/gcc-bugs/2001-09/msg00856.html ).

* The problem is probably related to PR 4415.

* It's a regression from gcc 3.0.
>How-To-Repeat:
gcc -O2 -march=k6 -c <filename>
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: