gcc-2.95.2 -fschedule-insns bug compiling jove

[TTK Ciar <ttk at gilliam dot users dot flyingcroc dot net>]

I ran across this while compiling jove.
The problem occurs with -O2 or -O3 but does not occur with -O1 or -O0,
or when -fschedule-insns is not given.
I have not yet verified that the error occurs in the latest snapshot.

> cc -O2 -fschedule-insns -DBSDPOSIX -c c.c
c.c: In function `Comment':
c.c:783: fixed or forbidden register 0 (ax) was spilled for class AREG.
c.c:783: This may be due to a compiler bug or to impossible asm
c.c:783: statements or clauses.
c.c:783: This is the instruction:
(insn 925 924 926 (parallel[ 
            (set (reg:SI 2 %ecx)
                (unspec:SI[ 
                        (mem:BLK (reg:SI 5 %edi) 0)
                        (const_int 0 [0x0])
                        (const_int 1 [0x1])
                    ]  0))
            (clobber (reg:SI 5 %edi))
        ] ) 411 {strlensi+1} (insn_list/j/c:REG_DEP_ANTI 918 (insn_list/j/c 924 (nil)))
    (expr_list:REG_UNUSED (reg:SI 5 %edi)
        (nil)))

(There is no inline asm in the source file.)

smokey> uname -a
FreeBSD smokey.westin16.flyingcroc.net 4.0-RELEASE FreeBSD 4.0-RELEASE #4: Fri Apr  7 10:42:09 PDT 2000     jkraft@smokey.westin16.flyingcroc.net:/usr/src/sys/compile/SMOKEY  i386

smokey> grep Pentium /var/log/messages | head -1
Apr  5 09:13:43 smokey /kernel: CPU: Pentium III/Pentium III Xeon (501.14-MHz 686-class CPU)

smokey> cc -v
Using builtin specs.
gcc version 2.95.2 19991024 (release)

This is for the 4.16 version of jove.  The sources are located at:
ftp://ftp.cs.toronto.edu/pub/moraes/jove/

  -- TTK