[Bug target/114148] gcc.target/i386/pr106010-7b.c FAILs

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114148

--- Comment #4 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
(In reply to ro@CeBiTec.Uni-Bielefeld.DE from comment #3)
> To investigate further, I've added comparison functions to a reduced
> version of pr106010-7b.c, with
> 
> void
> cmp_epi8 (_Complex unsigned char* a, _Complex unsigned char* b)
> {
>   for (int i = 0; i != N; i++)
>     if (a[i] != b[i])
>       {
> 	printf ("cmp_epi8: i = %d: a[i].r = %x a[i].i = %x b[i].r = %x b[i].i =
> %x\n",
> 		i, __real__ a[i], __imag__ a[i], __real__ b[i], __imag__ b[i]);
>       }
> }
> 
> This shows (when using _Complex unsigned char since on Solaris, char is
> signed by default)
> 
> cmp_epi8: i = 76: a[i].r = 0 a[i].i = 0 b[i].r = 88 b[i].i = 33
> cmp_epi8: i = 77: a[i].r = 0 a[i].i = 0 b[i].r = 6 b[i].i = 8
> cmp_epi8: i = 80: a[i].r = 0 a[i].i = 0 b[i].r = 3 b[i].i = 0
> 
> I've also noticed that the test result depends on the implementation of
> malloc used:
> 
> * With Solaris libc malloc, libmalloc, and watchmalloc, the test aborts.
> 
> * However, when using one of libbsdmalloc, libmapmalloc, libmtmalloc, or
>   libumem, the test works.
> 
> However, ISTM that the test is simply bogus: in avx_test
> 
> * epi8_src, epi8_dst are allocated with malloc, buffer contents undefined
> 
> * epi8_dst is cleared
> 
> * epi8_dst is initialized from p_init
> 
> * in foo_epi8, epi8_src[0] (an undefined value) is copied into first N
>   elements of epi8_dst
> 
> * epi8_dst is compared to epi8_src (with the remaining members of epi8_src
>   still undefined)
uoops, does below patch fix the testcase on Solaris/x86?

   memcpy (pd_src, p_init, 2 * N * sizeof (double));
-  memcpy (ps_dst, p_init, 2 * N * sizeof (float));
-  memcpy (epi64_dst, p_init, 2 * N * sizeof (long long));
-  memcpy (epi32_dst, p_init, 2 * N * sizeof (int));
-  memcpy (epi16_dst, p_init, 2 * N * sizeof (short));
-  memcpy (epi8_dst, p_init, 2 * N * sizeof (char));
+  memcpy (ps_src, p_init, 2 * N * sizeof (float));
+  memcpy (epi64_src, p_init, 2 * N * sizeof (long long));
+  memcpy (epi32_src, p_init, 2 * N * sizeof (int));
+  memcpy (epi16_src, p_init, 2 * N * sizeof (short));
+  memcpy (epi8_src, p_init, 2 * N * sizeof (char));

> 
> Why on earth would the rest of epi8_dst and epi8_src be identical if
> epi8_src was never initialized?
Guess, epi8_src is all zero, and epi8_dst if set as epi8_src[0] by foo_epi8.