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MDEV-21984: POWER crc32 acceleration - fix clang's behavior on versions >= 7

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Clang 7 changed the behavior of vec_xxpermdi in order to match GCC's
behavior.  After this change, code that used to work on Clang 6 stopped
to work on Clang >= 7.

Tested on Clang 6, 7, 8 and 9.

Reference: https://bugs.llvm.org/show_bug.cgi?id=38192

Upstream fix: 361aaf77a5
This commit is contained in:
Tulio Magno Quites Machado Filho 2020-03-26 13:13:31 +11:00 committed by Vicențiu-Marian Ciorbaru
parent 811e4409ce
commit 9aacda409d
1 changed files with 10 additions and 5 deletions
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15
extra/crc32-vpmsum/clang_workaround.h
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@ -39,7 +39,12 @@ __vector unsigned long long __builtin_pack_vector (unsigned long __a,
return __v;
}
#ifndef vec_xxpermdi
/*
* Clang 7 changed the behavior of vec_xxpermdi in order to provide the same
* behavior of GCC. That means code adapted to Clang >= 7 does not work on
* Clang <= 6. So, fallback to __builtin_unpack_vector() on Clang <= 6.
*/
#if !defined vec_xxpermdi || __clang_major__ <= 6
static inline
unsigned long __builtin_unpack_vector (__vector unsigned long long __v,
@ -62,9 +67,9 @@ static inline
unsigned long __builtin_unpack_vector_0 (__vector unsigned long long __v)
{
#if defined(__BIG_ENDIAN__)
return vec_xxpermdi(__v, __v, 0x0)[1];
#else
return vec_xxpermdi(__v, __v, 0x0)[0];
#else
return vec_xxpermdi(__v, __v, 0x3)[0];
#endif
}
@ -72,9 +77,9 @@ static inline
unsigned long __builtin_unpack_vector_1 (__vector unsigned long long __v)
{
#if defined(__BIG_ENDIAN__)
return vec_xxpermdi(__v, __v, 0x3)[1];
#else
return vec_xxpermdi(__v, __v, 0x3)[0];
#else
return vec_xxpermdi(__v, __v, 0x0)[0];
#endif
}
#endif /* vec_xxpermdi */