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Make penalty PRNG available for general use by compiler.

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This commit is contained in:
Mike Pall
2010-02-26 17:01:33 +01:00
parent 3c6cec0846
commit a0fbb05bf0
2 changed files with 10 additions and 10 deletions
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10
src/lj_trace.c
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@@ -310,14 +310,6 @@ void lj_trace_freestate(global_State *g)
/* -- Penalties and blacklisting ------------------------------------------ */
/* Trivial PRNG for randomization of penalties. */
static uint32_t penalty_prng(jit_State *J, int bits)
{
/* Yes, this LCG is very weak, but that doesn't matter for our use case. */
J->prngstate = J->prngstate * 1103515245 + 12345;
return J->prngstate >> (32-bits);
}
/* Blacklist a bytecode instruction. */
static void blacklist_pc(GCproto *pt, BCIns *pc)
{
@@ -333,7 +325,7 @@ static void penalty_pc(jit_State *J, GCproto *pt, BCIns *pc, TraceError e)
if (mref(J->penalty[i].pc, const BCIns) == pc) { /* Cache slot found? */
/* First try to bump its hotcount several times. */
val = ((uint32_t)J->penalty[i].val << 1) +
penalty_prng(J, PENALTY_RNDBITS);
LJ_PRNG_BITS(J, PENALTY_RNDBITS);
if (val > PENALTY_MAX) {
blacklist_pc(pt, pc); /* Blacklist it, if that didn't help. */
return;