[Bug c/46419] New: xmmintrin.h: _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps) returns false result in gcc >= 4.4

[Bug c/46419] New: xmmintrin.h: _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps) returns false result in gcc >= 4.4

[release_candidate at yahoo dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46419

           Summary: xmmintrin.h: _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps)
                    returns false result in gcc >= 4.4
           Product: gcc
           Version: 4.4.5
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: release_candidate@yahoo.com


Created attachment 22367
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22367
example code

Dear GCC developers,

I guess the patch set
<http://gcc.gnu.org/viewcvs?view=revision&revision=134558> broke the
_mm_cvtpu16_ps() and _mm_cvtpu8_ps() intrinsics.

For demonstration, please refer to the attached example. It is intended to
convert four chars (1,2,3,4) into a SSE float vector type (__m128) by using the
Intel intrinsics _mm_cvtpu8_ps() and _mm_setr_pi8().

The output of the program compiled with gcc-4.3 is:
    image: 1 2 3 4
    out4:  1 2 3 4
This result is correct, and complies with Intel's intrinsic docs 
<http://software.intel.com/sites/products/documentation/studio/composer/en-us/2011/compiler_c/intref_cls/common/intref_mmx_set.htm>
//
<http://software.intel.com/sites/products/documentation/studio/composer/en-us/2011/compiler_c/intref_cls/common/intref_sse_conversion.htm>,
as well as the output of icc compilation.

The output of gcc-4.4 and gcc-4.5 compilation is:
    image: 1 2 3 4
    out4:  3 4 1 2


I was able to trace this back the change set referred above. If I include the
old xmmintrin.h instead of the new header when using gcc-4.4, the result is
correct again. I didn't study the changes of rev. 134558  in detail, and I do
not know if the new algorithm is theoretically correct at all.


Could you please fix this bug?
I don't know about the other intrinsics touched by that patch.
Within this context, concerning the bug
<http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37496> might also be worth while.


Thanks,

Dirk

[Bug target/46419] [4.4, 4.5, 4.6 Regression] _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps) returns false result

[ubizjak at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46419

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |x86
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2010.11.10 22:14:13
          Component|c                           |target
         AssignedTo|unassigned at gcc dot       |ubizjak at gmail dot com
                   |gnu.org                     |
     Ever Confirmed|0                           |1
            Summary|xmmintrin.h: _mm_cvtpu16_ps |[4.4, 4.5, 4.6 Regression]
                   |(and hence _mm_cvtpu8_ps)   |_mm_cvtpu16_ps (and hence
                   |returns false result in gcc |_mm_cvtpu8_ps) returns
                   |>= 4.4                      |false result
   Target Milestone|---                         |4.4.6
           Severity|critical                    |normal

--- Comment #1 from Uros Bizjak <ubizjak at gmail dot com> 2010-11-10 22:14:13 UTC ---
Ugh...

Patch in testing:

Index: xmmintrin.h
===================================================================
--- xmmintrin.h    (revision 166558)
+++ xmmintrin.h    (working copy)
@@ -626,13 +626,13 @@
   __sign = __builtin_ia32_pcmpgtw ((__v4hi)0LL, (__v4hi)__A);

   /* Convert the four words to doublewords.  */
+  __losi = (__v2si) __builtin_ia32_punpcklwd ((__v4hi)__A, __sign);
   __hisi = (__v2si) __builtin_ia32_punpckhwd ((__v4hi)__A, __sign);
-  __losi = (__v2si) __builtin_ia32_punpcklwd ((__v4hi)__A, __sign);

   /* Convert the doublewords to floating point two at a time.  */
   __zero = (__v4sf) _mm_setzero_ps ();
-  __ra = __builtin_ia32_cvtpi2ps (__zero, __hisi);
-  __rb = __builtin_ia32_cvtpi2ps (__ra, __losi);
+  __ra = __builtin_ia32_cvtpi2ps (__zero, __losi);
+  __rb = __builtin_ia32_cvtpi2ps (__ra, __hisi);

   return (__m128) __builtin_ia32_movlhps (__ra, __rb);
 }
@@ -645,13 +645,13 @@
   __v4sf __zero, __ra, __rb;

   /* Convert the four words to doublewords.  */
+  __losi = (__v2si) __builtin_ia32_punpcklwd ((__v4hi)__A, (__v4hi)0LL);
   __hisi = (__v2si) __builtin_ia32_punpckhwd ((__v4hi)__A, (__v4hi)0LL);
-  __losi = (__v2si) __builtin_ia32_punpcklwd ((__v4hi)__A, (__v4hi)0LL);

   /* Convert the doublewords to floating point two at a time.  */
   __zero = (__v4sf) _mm_setzero_ps ();
-  __ra = __builtin_ia32_cvtpi2ps (__zero, __hisi);
-  __rb = __builtin_ia32_cvtpi2ps (__ra, __losi);
+  __ra = __builtin_ia32_cvtpi2ps (__zero, __losi);
+  __rb = __builtin_ia32_cvtpi2ps (__ra, __hisi);

   return (__m128) __builtin_ia32_movlhps (__ra, __rb);
 }

[Bug target/46419] [4.4, 4.5, 4.6 Regression] _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps) returns false result

[uros at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46419

--- Comment #2 from uros at gcc dot gnu.org 2010-11-10 23:00:08 UTC ---
Author: uros
Date: Wed Nov 10 23:00:01 2010
New Revision: 166569

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=166569
Log:
    PR middle-end/46419
    * config/i386/xmmintrin.h (_mm_cvtpi16_ps): Swap __hisi and __losi.
    (_mm_cvtpu16_ps): Ditto.

testsuite/ChangeLog:

    PR target/46419
    * gcc-target/i386/pr46419.c: New test.


Added:
    trunk/gcc/testsuite/gcc.target/i386/pr46419.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/xmmintrin.h
    trunk/gcc/testsuite/ChangeLog

[Bug target/46419] [4.4, 4.5, 4.6 Regression] _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps) returns false result

[uros at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46419

--- Comment #3 from uros at gcc dot gnu.org 2010-11-10 23:26:54 UTC ---
Author: uros
Date: Wed Nov 10 23:26:49 2010
New Revision: 166571

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=166571
Log:
    PR middle-end/46419
    * config/i386/xmmintrin.h (_mm_cvtpi16_ps): Swap __hisi and __losi.
    (_mm_cvtpu16_ps): Ditto.

testsuite/ChangeLog:

    PR target/46419
    * gcc-target/i386/pr46419.c: New test.


Added:
    branches/gcc-4_5-branch/gcc/testsuite/gcc.target/i386/pr46419.c
      - copied unchanged from r166569,
trunk/gcc/testsuite/gcc.target/i386/pr46419.c
Modified:
    branches/gcc-4_5-branch/gcc/ChangeLog
    branches/gcc-4_5-branch/gcc/config/i386/xmmintrin.h
    branches/gcc-4_5-branch/gcc/testsuite/ChangeLog

[Bug target/46419] [4.4, 4.5, 4.6 Regression] _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps) returns false result

[uros at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46419

--- Comment #4 from uros at gcc dot gnu.org 2010-11-10 23:28:10 UTC ---
Author: uros
Date: Wed Nov 10 23:28:03 2010
New Revision: 166572

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=166572
Log:
    PR middle-end/46419
    * config/i386/xmmintrin.h (_mm_cvtpi16_ps): Swap __hisi and __losi.
    (_mm_cvtpu16_ps): Ditto.

testsuite/ChangeLog:

    PR target/46419
    * gcc-target/i386/pr46419.c: New test.


Added:
    branches/gcc-4_4-branch/gcc/testsuite/gcc.target/i386/pr46419.c
      - copied unchanged from r166569,
trunk/gcc/testsuite/gcc.target/i386/pr46419.c
Modified:
    branches/gcc-4_4-branch/gcc/ChangeLog
    branches/gcc-4_4-branch/gcc/config/i386/xmmintrin.h
    branches/gcc-4_4-branch/gcc/testsuite/ChangeLog

[Bug target/46419] [4.4, 4.5, 4.6 Regression] _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps) returns false result

[ubizjak at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46419

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
                URL|                            |http://gcc.gnu.org/ml/gcc-p
                   |                            |atches/2010-11/msg01090.htm
                   |                            |l
         Resolution|                            |FIXED

--- Comment #5 from Uros Bizjak <ubizjak at gmail dot com> 2010-11-10 23:29:51 UTC ---
Fixed.

[Bug target/46419] [4.4, 4.5, 4.6 Regression] _mm_cvtpu16_ps (and hence _mm_cvtpu8_ps) returns false result

[ubizjak at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46419

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |cck0011 at yahoo dot com

--- Comment #6 from Uros Bizjak <ubizjak at gmail dot com> 2011-03-09 16:42:11 UTC ---
*** Bug 48036 has been marked as a duplicate of this bug. ***