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use register constraint instead of memory operand for riscv64 atomics 

the "A" constraint is simply for an address expression that's a single
register, but it's not yet supported by clang, and has no advantage
here over just using a register operand for the address. the latter is
actually preferable in the a_cas_p case because it avoids aliasing an
lvalue onto the memory.
This commit is contained in:
Rich Felker 2019-07-17 19:07:57 -04:00
parent 2dcbeabd91
commit f0eb2e77b2
1 changed files with 8 additions and 8 deletions
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16
arch/riscv64/atomic_arch.h
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@ -9,13 +9,13 @@ static inline int a_cas(volatile int *p, int t, int s)
{ {
int old, tmp; int old, tmp;
__asm__ __volatile__ ( __asm__ __volatile__ (
"\n1: lr.w.aqrl %0, %2\n" "\n1: lr.w.aqrl %0, (%2)\n"
" bne %0, %3, 1f\n" " bne %0, %3, 1f\n"
" sc.w.aqrl %1, %4, %2\n" " sc.w.aqrl %1, %4, (%2)\n"
" bnez %1, 1b\n" " bnez %1, 1b\n"
"1:" "1:"
: "=&r"(old), "=r"(tmp), "+A"(*p) : "=&r"(old), "=r"(tmp)
: "r"(t), "r"(s) : "r"(p), "r"(t), "r"(s)
: "memory"); : "memory");
return old; return old;
} }
@ -26,13 +26,13 @@ static inline void *a_cas_p(volatile void *p, void *t, void *s)
void *old; void *old;
int tmp; int tmp;
__asm__ __volatile__ ( __asm__ __volatile__ (
"\n1: lr.d.aqrl %0, %2\n" "\n1: lr.d.aqrl %0, (%2)\n"
" bne %0, %3, 1f\n" " bne %0, %3, 1f\n"
" sc.d.aqrl %1, %4, %2\n" " sc.d.aqrl %1, %4, (%2)\n"
" bnez %1, 1b\n" " bnez %1, 1b\n"
"1:" "1:"
: "=&r"(old), "=r"(tmp), "+A"(*(long *)p) : "=&r"(old), "=r"(tmp)
: "r"(t), "r"(s) : "r"(p), "r"(t), "r"(s)
: "memory"); : "memory");
return old; return old;
} }