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| author | Jim Wilson <wilson@cygnus.com> | 1997-08-28 20:04:19 +0000 |
|---|---|---|
| committer | Jim Wilson <wilson@gcc.gnu.org> | 1997-08-28 13:04:19 -0700 |
| commit | 00fc09e1496ef843e27f98c53f19cb6141993526 (patch) | |
| tree | 66dc80f24ea66452119a42a584107a662c0b3e2b | |
| parent | 2601ebca412b05d466bccccd2c4a74e1cec60c05 (diff) | |
| download | gcc-00fc09e1496ef843e27f98c53f19cb6141993526.zip gcc-00fc09e1496ef843e27f98c53f19cb6141993526.tar.gz gcc-00fc09e1496ef843e27f98c53f19cb6141993526.tar.bz2 | |
Fix x86 libio -O2 miscompilation problem.
* i386.c (ix86_expand_epilogue): Emit blockage instruction when pic.
From-SVN: r14992
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/config/i386/i386.c | 10 |
2 files changed, 14 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d135b4b..33fec6b 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +Thu Aug 28 13:01:43 1997 Jim Wilson <wilson@cygnus.com> + + * i386.c (ix86_expand_epilogue): Emit blockage instruction when pic. + Thu Aug 28 07:03:15 1997 Jeffrey A Law (law@cygnus.com) * version.c: Bump for latest snapshot. diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 35dbc62..d8d9757 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -2128,6 +2128,16 @@ ix86_expand_epilogue () xops[2] = stack_pointer_rtx; + /* When -fpic, we must emit a scheduling barrier, so that the instruction + that restores %ebx (which is PIC_OFFSET_TABLE_REGNUM), does not get + moved before any instruction which implicitly uses the got. This + includes any instruction which uses a SYMBOL_REF or a LABEL_REF. + + Alternatively, this could be fixed by making the dependence on the + PIC_OFFSET_TABLE_REGNUM explicit in the RTL. */ + if (flag_pic) + emit_insn (gen_blockage ()); + if (nregs > 1 || ! frame_pointer_needed) { if (frame_pointer_needed) |