Hello,
NOTE: the code examples below use fconstant's just to make the generated code
more readable, any compile-time constant like ma.SR lead to the same problem.
------------------------------------------------------------------------------
Lets start with the trivial example:
a = fconstant(float a, "");
b = fconstant(float b, "");
c = a / b;
process = *(c);
compiles to
virtual void instanceConstants(int sample_rate) {
fSampleRate = sample_rate;
fConst0 = a / b;
}
virtual void compute(int count, FAUSTFLOAT** RESTRICT inputs,
FAUSTFLOAT** RESTRICT outputs) {
FAUSTFLOAT* input0 = inputs[0];
FAUSTFLOAT* output0 = outputs[0];
for (int i0 = 0; i0 < count; i0 = i0 + 1) {
output0[i0] = FAUSTFLOAT(fConst0 * float(input0[i0]));
}
}
Good. Now lets use ffunction() with ffarity() > 0
a = fconstant(float a, "");
b = fconstant(float b, "");
c = a / b;
f1 = ffunction(float f1(float), "","");
process = f1 : *(c);
the generated code
virtual void instanceConstants(int sample_rate) {
fSampleRate = sample_rate;
fConst0 = a / b;
}
virtual void compute(int count, FAUSTFLOAT** RESTRICT inputs,
FAUSTFLOAT** RESTRICT outputs) {
FAUSTFLOAT* input0 = inputs[0];
FAUSTFLOAT* output0 = outputs[0];
for (int i0 = 0; i0 < count; i0 = i0 + 1) {
output0[i0] = FAUSTFLOAT(fConst0 *
f1(float(input0[i0])));
}
}
looks good too. However, if ffarity() == 0
a = fconstant(float a, "");
b = fconstant(float b, "");
c = a / b;
f0 = ffunction(float f0(), "","");
process = f0 : *(c);
then "a / b" is calculated at run time:
virtual void instanceConstants(int sample_rate) {
fSampleRate = sample_rate;
}
virtual void compute(int count, FAUSTFLOAT** RESTRICT inputs,
FAUSTFLOAT** RESTRICT outputs) {
FAUSTFLOAT* output0 = outputs[0];
for (int i0 = 0; i0 < count; i0 = i0 + 1) {
output0[i0] = FAUSTFLOAT(f0() * a / b);
}
}
and this looks like performance bug to me.
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More examples just in case,
a = fconstant(float a, "");
b = fconstant(float b, "");
c = a * b;
f0 = ffunction(float f0(), "","");
process = f0 : *(c);
demonstrates the same problem:
output0[i0] = FAUSTFLOAT(f0() * b * a);
however,
process = f0 * c; // should be equivalent to f0 : *(c)
compiles to
fConst0 = b * a;
...
output0[i0] = FAUSTFLOAT(fConst0 * f0());
------------------------------------------------------------------------------
Same problem with aterm's,
c = a + b;
f0 = ffunction(float f0(), "","");
process = f0 : +(c);
--->
output0[i0] = FAUSTFLOAT(a + f0() + b);
while "process = f0 + c" works correctly.
Oleg.
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