[Bug target/66821] New: reassoc-37.c fails on -march=pentium

[Bug target/66821] New: reassoc-37.c fails on -march=pentium

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

            Bug ID: 66821
           Summary: reassoc-37.c fails on -march=pentium
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: julia.koval at intel dot com
  Target Milestone: ---

FAIL: gcc.dg/tree-ssa/reassoc-37.c scan-tree-dump optimized
"(8784908|0x0*860c0c)"
FAIL: gcc.dg/tree-ssa/reassoc-37.c scan-tree-dump optimized "(<<|>>)"

./gcc -m32 reassoc-37.c
193.t.optimised pass generates:
  <bb 2>:
  _26 = (unsigned int) x_2(D);
  if (_26 > 23)
    goto <bb 4>;
  else
    goto <bb 3>;

  <bb 3>:
  _28 = 8784908 >> x_2(D);
  _29 = _28 & 1;
  _34 = ~_28;
  _32 = _34 & 1;
  _30 = (_Bool) _34;
  if (_30 != 0)
    goto <bb 4>;
  else
    goto <bb 5>;

./gcc -m32 -march=pentium
193.t.optimised pass generates:
<bb 2>:
  _22 = (unsigned int) x_2(D);
  _23 = _22 & 4294967287;
  _24 = _23 + 4294967294;
  if (_24 > 1)
    goto <bb 3>;
  else
    goto <bb 6>;

  <bb 3>:
  _20 = _22 + 4294967279;
  if (_20 > 1)
    goto <bb 4>;
  else
    goto <bb 6>;

[Bug target/66821] reassoc-37.c fails on -march=pentium

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
Which code is better?

[Bug target/66821] reassoc-37.c fails on -march=pentium

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #2 from Yulia Koval <julia.koval at intel dot com> ---
Well, second one looks better, but first one generates 9b smaller code.
Can we disable this test for this target if it is not an issue?

[Bug target/66821] reassoc-37.c fails on -march=pentium

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Yulia Koval from comment #2)
> Well, second one looks better, but first one generates 9b smaller code.
> Can we disable this test for this target if it is not an issue?

This is a tuning issue.  We want smaller codes for IA MCU.  Please check
-march=iamcu, not -march=pentium.  We can't change Pentium tuning.  But
we can change IA MCU tuning.

[Bug target/66821] reassoc-37.c fails on -march=pentium

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #4 from Yulia Koval <julia.koval at intel dot com> ---
The issue remains for -march=iamcu but not for -miamcu.

[Bug target/66821] reassoc-37.c fails on -march=pentium

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Yulia Koval from comment #4)
> The issue remains for -march=iamcu but not for -miamcu.

Let's fix -march=iamcu.

[Bug target/66821] reassoc-37.c fails on -march=pentium

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #6 from Yulia Koval <julia.koval at intel dot com> ---
msticlxl58$ size miam
   text    data     bss     dec     hex filename
     72       0       0      72      48 miam
msticlxl58$ size march
   text    data     bss     dec     hex filename
     81       0       0      81      51 march

[Bug target/66821] reassoc-37.c fails on -march=pentium

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Yulia Koval from comment #6)
> msticlxl58$ size miam
>    text    data     bss     dec     hex filename
>      72       0       0      72      48 miam
> msticlxl58$ size march
>    text    data     bss     dec     hex filename
>      81       0       0      81      51 march

Which one is -march=iamcu?

[Bug target/66821] reassoc-37.c fails on -march=pentium

[julia.koval at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #8 from Yulia Koval <julia.koval at intel dot com> ---
(In reply to H.J. Lu from comment #7)
> (In reply to Yulia Koval from comment #6)
> > msticlxl58$ size miam
> >    text    data     bss     dec     hex filename
> >      72       0       0      72      48 miam
> > msticlxl58$ size march
> >    text    data     bss     dec     hex filename
> >      81       0       0      81      51 march
> 
> Which one is -march=iamcu?

miam is -miamcu, the same as just "-m32"
march is -march=iamcu

[Bug target/66821] reassoc-37.c fails on -march=iamcu

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-07-09
     Ever confirmed|0                           |1

--- Comment #9 from H.J. Lu <hjl.tools at gmail dot com> ---
A patch is posted at

https://gcc.gnu.org/ml/gcc-patches/2015-07/msg00806.html

[Bug target/66821] reassoc-37.c fails on -march=iamcu

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |6.0

--- Comment #11 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed.

[Bug target/66821] reassoc-37.c fails on -march=iamcu

[hjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66821

--- Comment #12 from hjl at gcc dot gnu.org <hjl at gcc dot gnu.org> ---
Author: hjl
Date: Mon Aug 24 15:31:02 2015
New Revision: 227133

URL: https://gcc.gnu.org/viewcvs?rev=227133&root=gcc&view=rev
Log:
Add a testcase for PR target/66821

        PR target/66821
        * gcc.target/i386/pr66821.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr66821.c
Modified:
    trunk/gcc/testsuite/ChangeLog