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Remove pow() splitting and cleanup backends.

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This commit is contained in:
Mike Pall
2020-05-23 21:33:01 +02:00
parent 5655be4546
commit b2307c8ad8
14 changed files with 95 additions and 222 deletions
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20
src/lj_opt_narrow.c
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@@ -593,10 +593,10 @@ TRef lj_opt_narrow_pow(jit_State *J, TRef rb, TRef rc, TValue *vb, TValue *vc)
/* Narrowing must be unconditional to preserve (-x)^i semantics. */
if (tvisint(vc) || numisint(numV(vc))) {
int checkrange = 0;
/* Split pow is faster for bigger exponents. But do this only for (+k)^i. */
/* pow() is faster for bigger exponents. But do this only for (+k)^i. */
if (tref_isk(rb) && (int32_t)ir_knum(IR(tref_ref(rb)))->u32.hi >= 0) {
int32_t k = numberVint(vc);
if (!(k >= -65536 && k <= 65536)) goto split_pow;
if (!(k >= -65536 && k <= 65536)) goto force_pow_num;
checkrange = 1;
}
if (!tref_isinteger(rc)) {
@@ -607,19 +607,11 @@ TRef lj_opt_narrow_pow(jit_State *J, TRef rb, TRef rc, TValue *vb, TValue *vc)
TRef tmp = emitir(IRTI(IR_ADD), rc, lj_ir_kint(J, 65536));
emitir(IRTGI(IR_ULE), tmp, lj_ir_kint(J, 2*65536));
}
return emitir(IRTN(IR_POW), rb, rc);
} else {
force_pow_num:
rc = lj_ir_tonum(J, rc); /* Want POW(num, num), not POW(num, int). */
}
split_pow:
/* FOLD covers most cases, but some are easier to do here. */
if (tref_isk(rb) && tvispone(ir_knum(IR(tref_ref(rb)))))
return rb; /* 1 ^ x ==> 1 */
rc = lj_ir_tonum(J, rc);
if (tref_isk(rc) && ir_knum(IR(tref_ref(rc)))->n == 0.5)
return emitir(IRTN(IR_FPMATH), rb, IRFPM_SQRT); /* x ^ 0.5 ==> sqrt(x) */
/* Split up b^c into exp2(c*log2(b)). Assembler may rejoin later. */
rb = emitir(IRTN(IR_FPMATH), rb, IRFPM_LOG2);
rc = emitir(IRTN(IR_MUL), rb, rc);
return emitir(IRTN(IR_FPMATH), rc, IRFPM_EXP2);
return emitir(IRTN(IR_POW), rb, rc);
}
/* -- Predictive narrowing of induction variables ------------------------- */