[Bug target/14981] [3.4/3.5 Regression] ICE in _mm_xor_pd for SSE2 with -O1

["reichelt at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Additional Comments From reichelt at gcc dot gnu dot org  2004-08-17 02:51 -------
Here's a more detailed description what's happening:
The testcase can be reduced to

==========================================================
typedef int v2df __attribute__ ((mode (V2DF)));

v2df foo(double d)
{
    v2df x={0.0,d};
    v2df y={0.0,0.0};
    return __builtin_ia32_xorpd(x,y);
}
==========================================================

which crashes the compiler when compiled with "gcc -O -msse2".
The crash on the 3.3 branch (3.3 - 3.3.5) is in subreg_hard_regno,
the crash in the 3.4 branch (3.4.0 - 3.4.2) is immed_double_const
(both in emit-rtl.c).

These are actuelly two distinct problems, one with non-constant parameters,
and one with constant parameters which can be shown with the following
testcases:

The first one triggers the 3.3.x failure:
==========================================================
typedef int v2df __attribute__ ((mode (V2DF)));

v2df foo(double d)
{
    v2df x={0.0,d};
    return __builtin_ia32_xorpd(x,x);
}
==========================================================
Since the mode V2DF was introduced in 3.3 this is not a regression,
but a fix on the 3.3 branch would be nice anyway IMHO.

The second one triggers the 3.4.x failure:
==========================================================
typedef int v2df __attribute__ ((mode (V2DF)));

void foo()
{
    v2df x={0.0,0.0};
    __builtin_ia32_xorpd(x,x);
}
==========================================================
Since this worked in 3.3 this is a 3.4 regression.


Btw, the header file emmintrin.h was introduced in 3.3.3, so the
original example couldn't be compiled in 3.3 - 3.3.2.
The 3.3.2 version mentioned in the original bug report seems to be
Red Hat's own version with additional patches.


Alas that's not all. By specifying "-msse" instead of "-O -msse2"
the last testcase crashes the 3.4 branch and mainline in
extract_constrain_insn_cached, at recog.c:2000 (thus a 3.4/3.5 regression)
If I don't even use "-msse", the 3.3 branch fails in
ix86_function_arg_boundary, at config/i386/i386.c:2414.

Btw, I removed the known-to-work/fail entries since they differ
from testcase to testcase.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |reichelt at gcc dot gnu dot
                   |                            |org
           Severity|normal                      |critical
           Keywords|                            |monitored
      Known to fail|3.4.0 3.3.4                 |
      Known to work|3.5.0 3.3.3                 |
            Summary|[3.3/3.4 Regression] ICE in |[3.4/3.5 Regression] ICE in
                   |_mm_xor_pd for SSE2  with - |_mm_xor_pd for SSE2 with -O1
                   |O1                          |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14981