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libitm: Avoid non-portable x86 branch prediction mnemonic.

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From-SVN: r181233
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Richard Henderson 2011-11-09 11:51:49 -08:00 • committed by Richard Henderson
parent a5b3d713cc
commit 8ee9fac21e
2 changed files with 8 additions and 3 deletions
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3
libitm/ChangeLog
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@ -1,5 +1,8 @@
2011-11-09 Richard Henderson <rth@redhat.com>
* config/x86/cacheline.h (gtm_cacheline::store_mask): Use .byte
to emit branch prediction hint.
* config/x86/sjlj.S: Protect elf directives with __ELF__.
Protect .note.GNU-stack with __linux__.

8
libitm/config/x86/cacheline.h
View file

@ -144,7 +144,7 @@ gtm_cacheline::operator= (const gtm_cacheline & __restrict s)
}
#endif
// ??? Support masked integer stores more efficiently with an unlocked cmpxchg
// Support masked integer stores more efficiently with an unlocked cmpxchg
// insn. My reasoning is that while we write to locations that we do not wish
// to modify, we do it in an uninterruptable insn, and so we either truely
// write back the original data or the insn fails -- unlike with a
@ -171,7 +171,8 @@ gtm_cacheline::store_mask (uint32_t *d, uint32_t s, uint8_t m)
"and %[m], %[n]\n\t"
"or %[s], %[n]\n\t"
"cmpxchg %[n], %[d]\n\t"
"jnz,pn 0b"
".byte 0x2e\n\t" // predict not-taken, aka jnz,pn
"jnz 0b"
: [d] "+m"(*d), [n] "=&r" (n), [o] "+a"(o)
: [s] "r" (s & bm), [m] "r" (~bm));
}
@ -198,7 +199,8 @@ gtm_cacheline::store_mask (uint64_t *d, uint64_t s, uint8_t m)
"and %[m], %[n]\n\t"
"or %[s], %[n]\n\t"
"cmpxchg %[n], %[d]\n\t"
"jnz,pn 0b"
".byte 0x2e\n\t" // predict not-taken, aka jnz,pn
"jnz 0b"
: [d] "+m"(*d), [n] "=&r" (n), [o] "+a"(o)
: [s] "r" (s & bm), [m] "r" (~bm));
#else