Re: bin/46978: internal compiler error building qt4-libs

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

New test case is:

typedef int __attribute__((vector_size(8))) m64;
m64 _mm_setzero_si64 ();
m64 _negate (m64, m64);
void
qt_blend_color_argb_x86 ()
{
    m64 mmx_0x00ff = _mm_setzero_si64 ();
    m64 mmx_0x0000 = _mm_setzero_si64 ();
    m64 ca;
    m64 ica = _negate (ca, mmx_0x00ff);
}

Compiling this with -mmx -O2 results in the given crash.
Unpatched gcc shows the same behavior with -mpreferred-stack-boundary=2.

Best bet so far is that the memory alignment is computed too early,
before the stack alignment is finalized.

Joerg