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* [Bug rtl-optimization/37490]  New: [4.4 Regression] IRA causes FP code to have more spills
@ 2008-09-11 23:46 pinskia at gcc dot gnu dot org
  2008-09-11 23:46 ` [Bug rtl-optimization/37490] " pinskia at gcc dot gnu dot org
                   ` (12 more replies)
  0 siblings, 13 replies; 14+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2008-09-11 23:46 UTC (permalink / raw)
  To: gcc-bugs

I had quickly looked at PR 37488 and decided to try it out on PPC and noticed
that IRA generates worse code than what was being generated before.
Here is a simple testcase which does not have any indirect gotos in it:
void g(void);
const void* test(int action, void* ptr, int a, int *b)
{
   if (action == 0) {
      return 0;
   } else {
      char* ip = ptr;
      double reg_f_a;
      double reg_f[1];
      reg_f_a = 0.0;
      reg_f[0] = 0.0;
      if(a) goto L2;
L1: {
      int t1 = *(int*)(++ip);
      reg_f_a = reg_f_a + reg_f[t1];
      g();
      if(*(++b)) goto L1;
   }
L2:
      g();
      *(double*)ptr = reg_f_a;
   }
   return 0;
}

--- CUT ---
-       fmr 31,0
+       std 0,128(1)
+       lfd 31,128(1)

-       fmr 31,0
-       mr 31,4
-       addi 29,1,112
+       std 0,128(1)
+       mr 29,4
+       lfd 31,128(1)
+       addi 28,1,112

For some reason IRA decides it is better to use the GPRs for 0.0 than it is to
use the FPRs.


-- 
           Summary: [4.4 Regression] IRA causes FP code to have more spills
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37490


^ permalink raw reply	[flat|nested] 14+ messages in thread
end of thread, other threads:[~2010-02-25 18:56 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-09-11 23:46 [Bug rtl-optimization/37490] New: [4.4 Regression] IRA causes FP code to have more spills pinskia at gcc dot gnu dot org
2008-09-11 23:46 ` [Bug rtl-optimization/37490] " pinskia at gcc dot gnu dot org
2008-09-11 23:49 ` pinskia at gcc dot gnu dot org
2008-09-11 23:55 ` pinskia at gcc dot gnu dot org
2008-09-13 12:43 ` rguenth at gcc dot gnu dot org
2008-10-22  3:11 ` mmitchel at gcc dot gnu dot org
2008-12-24 23:03 ` pinskia at gcc dot gnu dot org
2009-02-16  9:12 ` bonzini at gnu dot org
2009-02-17 20:48 ` pinskia at gcc dot gnu dot org
2009-04-21 15:59 ` [Bug rtl-optimization/37490] [4.4/4.5 " jakub at gcc dot gnu dot org
2009-07-22 10:35 ` jakub at gcc dot gnu dot org
2009-10-15 12:54 ` jakub at gcc dot gnu dot org
2010-01-21 13:15 ` jakub at gcc dot gnu dot org
2010-02-25 18:56 ` law at redhat dot com

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