[Bug target/34422] Bootstrap error with --enable-fixed-point (configure should reject --enable-fixed-point on platforms that don't support it)

["egallager at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=34422

Eric Gallager <egallager at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2008-01-22 00:58:46         |2022-5-24
                 CC|                            |Chao-Ying.Fu at imgtec dot com,
                   |                            |schwab at gcc dot gnu.org

--- Comment #9 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Eric Gallager from comment #8)
> (In reply to Eric Gallager from comment #6)
> > So could the configure script error out earlier, then, if it is passed
> > --enable-fixed-point for a target other than MIPS?
> 
> I'm going to re-title and self-assign on that basis.

...ok, so wait, looking at gcc/configure.ac, it looks like there's already code
to ignore --enable-fixed-point for unsupported targets? (current list of
supported targets is arm, mips, and loongarch, for reference)
Furthermore, it looks like that code has been there since Chao-ying Fu first
added the flag in r0-82714-gab22c1fa94acc0... so why didn't it work and result
in the flag being properly ignored? I just checked again and the error still
occurs; now it reads:

/Users/ericgallager/gcc_newgit/abcdefghijklmnopqrstuvwxyz_01234567890.build/./gcc/xgcc
-B/Users/ericgallager/gcc_newgit/abcdefghijklmnopqrstuvwxyz_01234567890.build/./gcc/
-B/usr/local/x86_64-apple-darwin20/bin/ -B/usr/local/x86_64-apple-darwin20/lib/
-isystem /usr/local/x86_64-apple-darwin20/include -isystem
/usr/local/x86_64-apple-darwin20/sys-include    -g -O2 -g -Os -O2  -g -O2 -g
-Os -DIN_GCC -fPIC   -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual
-Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem
./include   -mmacosx-version-min=10.4 -fno-common -g -DIN_LIBGCC2
-fbuilding-libgcc -fno-stack-protector   -mmacosx-version-min=10.4 -fno-common
-I. -I. -I../.././gcc -I../../../libgcc -I../../../libgcc/.
-I../../../libgcc/../gcc -I../../../libgcc/../include  -DHAVE_CC_TLS
-DUSE_EMUTLS  -o _addQQ_s.o -MT _addQQ_s.o -MD -MP -MF _addQQ_s.dep -DSHARED
-DL_add -DQQ_MODE -c ../../../libgcc/fixed-bit.c
In file included from ../../../libgcc/fixed-bit.c:55:
../../../libgcc/fixed-bit.h:64:1: error: unable to emulate 'QQ'
   64 | typedef          _Fract QQtype  __attribute__ ((mode (QQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:65:1: error: unable to emulate 'UQQ'
   65 | typedef unsigned _Fract UQQtype __attribute__ ((mode (UQQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:66:1: error: unable to emulate 'HQ'
   66 | typedef          _Fract HQtype  __attribute__ ((mode (HQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:67:1: error: unable to emulate 'UHQ'
   67 | typedef unsigned _Fract UHQtype __attribute__ ((mode (UHQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:68:1: error: unable to emulate 'HA'
   68 | typedef          _Fract HAtype  __attribute__ ((mode (HA)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:69:1: error: unable to emulate 'UHA'
   69 | typedef unsigned _Fract UHAtype __attribute__ ((mode (UHA)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:84:1: error: unable to emulate 'SQ'
   84 | typedef          _Fract SQtype  __attribute__ ((mode (SQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:85:1: error: unable to emulate 'USQ'
   85 | typedef unsigned _Fract USQtype __attribute__ ((mode (USQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:86:1: error: unable to emulate 'SA'
   86 | typedef          _Fract SAtype  __attribute__ ((mode (SA)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:87:1: error: unable to emulate 'USA'
   87 | typedef unsigned _Fract USAtype __attribute__ ((mode (USA)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:98:1: error: unable to emulate 'DQ'
   98 | typedef          _Fract DQtype  __attribute__ ((mode (DQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:99:1: error: unable to emulate 'UDQ'
   99 | typedef unsigned _Fract UDQtype __attribute__ ((mode (UDQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:100:1: error: unable to emulate 'DA'
  100 | typedef          _Fract DAtype  __attribute__ ((mode (DA)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:101:1: error: unable to emulate 'UDA'
  101 | typedef unsigned _Fract UDAtype __attribute__ ((mode (UDA)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:112:1: error: unable to emulate 'TQ'
  112 | typedef          _Fract TQtype  __attribute__ ((mode (TQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:113:1: error: unable to emulate 'UTQ'
  113 | typedef unsigned _Fract UTQtype __attribute__ ((mode (UTQ)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:114:1: error: unable to emulate 'TA'
  114 | typedef          _Fract TAtype  __attribute__ ((mode (TA)));
      | ^~~~~~~
../../../libgcc/fixed-bit.h:115:1: error: unable to emulate 'UTA'
  115 | typedef unsigned _Fract UTAtype __attribute__ ((mode (UTA)));
      | ^~~~~~~
../../../libgcc/fixed-bit.c: In function '__addqq3':
../../../libgcc/fixed-bit.c:60:1: internal compiler error: in
classify_argument, at config/i386/i386.cc:2494
   60 | {
      | ^
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
See <https://gcc.gnu.org/bugs/> for instructions.
make[1]: *** [_addQQ_s.o] Error 1
make: *** [all-target-libgcc] Error 2

cc-ing people who touched the code in gcc/configure.ac that ought to cause the
flag to be ignored most recently, according to git blame.