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[PATCH, x86, 63534] Fix '-p' profile for 32 bit PIC mode


Hi,

The patch fixes profile in 32bits PIC mode (only -p option affected).

x86 bootstrap, make check passed

spec2000 o2 -p train data on Corei7:
CINT -5%
CFP  +1,5
compared to a compiler before "enabling ebx".

There is a potential performance improve after the patch applied
suggested by Jakub:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63534#c8
There is opened bug on this: PR63527. However the fix of the bug is
more complicated.

Is it ok?

ChangeLog

2014-10-16  Evgeny Stupachenko  <evstupac@gmail.com>

        PR target/63534
        * config/i386/i386.c (x86_function_profiler): Add GOT register init
        for mcount call.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index a3ca2ed..5117572 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -39119,11 +39126,15 @@ x86_function_profiler (FILE *file, int
labelno ATTRIBUTE_UNUSED)
     }
   else if (flag_pic)
     {
+      fprintf (file,"\tpush\t%%ebx\n");
+      fprintf (file,"\tcall\t__x86.get_pc_thunk.bx\n");
+      fprintf (file,"\taddl\t$_GLOBAL_OFFSET_TABLE_, %%ebx\n");
 #ifndef NO_PROFILE_COUNTERS
       fprintf (file, "\tleal\t%sP%d@GOTOFF(%%ebx),%%"
PROFILE_COUNT_REGISTER "\n",
               LPREFIX, labelno);
 #endif
       fprintf (file, "1:\tcall\t*%s@GOT(%%ebx)\n", mcount_name);
+      fprintf (file,"\tpop\t%%ebx\n");
     }
   else
     {


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