optimization/3861: K6 optimization broken when compiling libstdc++-v3

[jlaako@pp.htv.fi]

>Number:         3861
>Category:       optimization
>Synopsis:       K6 optimization broken when compiling libstdc++-v3
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-legal-code
>Submitter-Id:   net
>Arrival-Date:   Sat Jul 28 15:16:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Jussi Laako
>Release:        3.0.1
>Organization:
>Environment:
i586-linux
>Description:
With K6 optimization (-march=k6 -mcpu=k6) make boostrap fails when compiling libstdc++-v3, but compiles with pentium optimization (-march=i586 -mcpu=i586).

Following command fails with following error:

/usr/local/src/gcc-objdir/gcc/xgcc -B/usr/local/src/gcc-objdir/gcc/ -nostdinc++ -L/usr/local/src/gcc-objdir/i586-pc-linux-gnu/libstdc++-v3/src -L/usr/local/src/gcc-objdir/i586-pc-linux-gnu/libstdc++-v3/src/.libs -B/usr/local/i586-pc-linux-gnu/bin/ -B/usr/local/i586-pc-linux-gnu/lib/ -isystem /usr/local/i586-pc-linux-gnu/include -nostdinc++ -I/usr/local/src/gcc-objdir/i586-pc-linux-gnu/libstdc++-v3/include/i586-pc-linux-gnu -I/usr/local/src/gcc-objdir/i586-pc-linux-gnu/libstdc++-v3/include -I../../../../gcc/libstdc++-v3/libsupc++ -I../../../../gcc/libstdc++-v3/libmath -mcpu=k6 -march=k6 -O2 -mfancy-math-387 -D_GNU_SOURCE -fno-implicit-templates -Wall -Wno-format -W -Wwrite-strings -Winline -fdiagnostics-show-location=once -ffunction-sections -fdata-sections -g -c ../../../../gcc/libstdc++-v3/src/ios.cc -o ios.o


../../../../gcc/libstdc++-v3/src/ios.cc: In static member function `static void
   std::ios_base::Init::_S_ios_create(bool)':
../../../../gcc/libstdc++-v3/src/ios.cc:173: Unrecognizable insn:
(insn 1652 15 1656 (parallel[
            (set (reg:SI 3 ebx [215])
                (const_int 0 [0x0]))
            (clobber (reg:CC 17 flags))
        ] ) -1 (insn_list:REG_DEP_ANTI 1621 (nil))
    (expr_list:REG_UNUSED (reg:CC 17 flags)
        (nil)))
../../../../gcc/libstdc++-v3/src/ios.cc:173: Internal compiler error in
   insn_default_length, at insn-attrtab.c:223
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL: http://www.gnu.org/software/gcc/bugs.html > for instructions.
>How-To-Repeat:
CFLAGS="-march=k6 -mcpu=k6 -O2 -mfancy-math-387"
>Fix:

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