[LLVMdev] Optimization of calls to functions without side effects (from Kaleidoscope example)

[Rob Pieke]

> You need to set attribute ReadOnly on the sin / cos functions, using
> Function::addFnAttr(Attribute) for example.

Hmm ... I tried setting that right after Function::Create but I still get the same result (though flagged with "readonly")

declare double @sin(double) readonly

declare double @cos(double) readonly

define double @foo(double %x) readonly {
entry:
  %calltmp = call double @sin(double %x)
  %calltmp1 = call double @sin(double %x)
  %multmp = fmul double %calltmp, %calltmp1
  %calltmp2 = call double @cos(double %x)
  %calltmp3 = call double @cos(double %x)
  %multmp4 = fmul double %calltmp2, %calltmp3
  %addtmp = fadd double %multmp, %multmp4
  ret double %addtmp
}