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Revert to trival pow() optimizations to prevent inaccuracies.

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This commit is contained in:
Mike Pall
2022-03-08 19:44:10 +01:00
parent aa0550e3f0
commit 96d6d50320
18 changed files with 45 additions and 157 deletions
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44
src/lj_vmmath.c
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@@ -30,52 +30,12 @@ LJ_FUNCA double lj_wrap_sinh(double x) { return sinh(x); }
LJ_FUNCA double lj_wrap_cosh(double x) { return cosh(x); }
LJ_FUNCA double lj_wrap_tanh(double x) { return tanh(x); }
LJ_FUNCA double lj_wrap_atan2(double x, double y) { return atan2(x, y); }
LJ_FUNCA double lj_wrap_pow(double x, double y) { return pow(x, y); }
LJ_FUNCA double lj_wrap_fmod(double x, double y) { return fmod(x, y); }
#endif
/* -- Helper functions ---------------------------------------------------- */
/* Unsigned x^k. */
static double lj_vm_powui(double x, uint32_t k)
{
double y;
lj_assertX(k != 0, "pow with zero exponent");
for (; (k & 1) == 0; k >>= 1) x *= x;
y = x;
if ((k >>= 1) != 0) {
for (;;) {
x *= x;
if (k == 1) break;
if (k & 1) y *= x;
k >>= 1;
}
y *= x;
}
return y;
}
/* Signed x^k. */
double lj_vm_powi(double x, int32_t k)
{
if (k > 1)
return lj_vm_powui(x, (uint32_t)k);
else if (k == 1)
return x;
else if (k == 0)
return 1.0;
else
return 1.0 / lj_vm_powui(x, (uint32_t)-k);
}
double lj_vm_pow(double x, double y)
{
int32_t k = lj_num2int(y);
if ((k >= -65536 && k <= 65536) && y == (double)k)
return lj_vm_powi(x, k);
else
return pow(x, y);
}
double lj_vm_foldarith(double x, double y, int op)
{
switch (op) {
@@ -84,7 +44,7 @@ double lj_vm_foldarith(double x, double y, int op)
case IR_MUL - IR_ADD: return x*y; break;
case IR_DIV - IR_ADD: return x/y; break;
case IR_MOD - IR_ADD: return x-lj_vm_floor(x/y)*y; break;
case IR_POW - IR_ADD: return lj_vm_pow(x, y); break;
case IR_POW - IR_ADD: return pow(x, y); break;
case IR_NEG - IR_ADD: return -x; break;
case IR_ABS - IR_ADD: return fabs(x); break;
#if LJ_HASJIT