Re: Battle-plan for CTFE

[Stefam Koch via Digitalmars-d-announce]

On Tuesday, 25 October 2016 at 09:36:12 UTC, Stefam Koch wrote:

On Monday, 24 October 2016 at 06:37:12 UTC, Rory McGuire wrote:

Cool, thanks for the feedback.

I have take care of the blocker for now.

I turns out my tests contained wrong code that reused a register for multiple purposes.

LLVM does not like that.

So it assumed the wrong things while optimising and went into the wrong direction makeing complete bogus out of valid code.

First perf data is in

The is measured with time src/dmd -c -ctfe-bc

old interpreter (without -ctfe-bc) :

real    0m6.839s
user    0m6.423s
sys     0m0.407s

new interpreter (-ctfe-bc)

real    0m0.549s
user    0m0.547s
sys     0m0.000s

LLVM Backend (-ctfe-bc -version=UseLLVMBackend) :

real    0m0.039s
user    0m0.027s
sys     0m0.010s


The compiled code was :
int bug6498(int x)
{
    int n = 0;
    while (n < x)
        ++n;
    return n;
}
static assert(bug6498(10_000_000)==10_000_000);