BUG: Creating shared C++ libs using -march=pentiumpro broken on the release branch

[Manfred Hollstein]

Hi there,

Since the   patch   to  "load_pic_register"   has been    applied   to
config/i386/i386.md  on  the  "gcc-2_95-branch", creating  shared  C++
libraries using the "-march=pentiumpro" flag  became impossible. I did
an update on the branch today  (2000/06/28 16:24:00 +0200), configured
like this:

$ env CC=gcc CFLAGS="-O9 -march=pentiumpro -fomit-frame-pointer"	\
      CXXFLAGS="-O9 -march=pentiumpro -g" LDFLAGS= LINGUAS="de es fr it"\
  /bin/sh ../gcc-2.95.3/configure --host=i686-redhat6-linux-gnu		\
	--target=i686-redhat6-linux-gnu --srcdir=../gcc-2.95.3		\
	--prefix=/opt/gnu --exec-prefix=/opt/gnu/H-ia32-linux		\
	--with-gnu-as --with-gnu-ld --enable-shared			\
	--enable-version-specific-runtime-libs --enable-threads=yes	\
	--with-local-prefix=/opt/gnu --enable-languages=c,gcov,c++	\
	--enable-nls --verbose

followed by a

$ make bootstrap

So far,  no  problems. But,  running "make    check" reveals  lots  of
failures in the C++ are, all of which are similar to this:

/home/gnu/work/GNU/gcc-2.95.3-i686-redhat6-linux-gnu/i686-redhat6-linux-gnu//libstdc++/libstdc++.so: undefined reference to `LPR0'
collect2: ld returned 1 exit status

I tracked it down today to this change:

diff -rcp gcc-2.95.2/gcc/config/i386/i386.md gcc-2.95.3/gcc/config/i386/i386.md
*** gcc-2.95.2/gcc/config/i386/i386.md	Tue Sep  7 09:45:42 1999
--- gcc-2.95.3/gcc/config/i386/i386.md	Sat Jan 22 16:02:52 2000
***************
*** 1,5 ****
  ; GCC machine description for Intel X86.
! ;; Copyright (C) 1988, 94, 95, 96, 97, 98, 1999 Free Software Foundation, Inc.
  ;; Mostly by William Schelter.
  
  ;; This file is part of GNU CC.
--- 1,5 ----
  ; GCC machine description for Intel X86.
! ;; Copyright (C) 1988, 94-99, 2000 Free Software Foundation, Inc.
  ;; Mostly by William Schelter.
  
  ;; This file is part of GNU CC.
*************** byte_xor_operation:
*** 8187,8192 ****
--- 8187,8201 ----
  
  (define_expand "exception_receiver"
    [(const_int 0)]
+   "flag_pic"
+   "
+ {
+   load_pic_register ();
+   DONE;
+ }")
+ 
+ (define_expand "builtin_setjmp_receiver"
+   [(label_ref (match_operand 0 "" ""))]
    "flag_pic"
    "
  {

Note, there's not even a ChangeLog entry for it... You can compile the
attached builtinbuf.ii like this:

$ gcc -march=pentiumpro -fvtable-thunks -fno-implicit-templates -fpic -c --save-temps builtinbuf.ii

and  then grep  for   LPR0, which will  only   show references  but no
definitions for it :-( Essentially, builtinbuf.ii does not contain any
definitions  other  than one frame  descriptor  plus the usual pthread
weak symbols (look at the attached builtinbuf.s).

This does not happen with gcc-2.95.2 or on the mainline.

If someone has a patch for it, that would be fine; otherwise, I'll dig
around further myself if time permits.

Cheers.

l8er
manfred

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