Asm and CTFE

[bearophile]

This code doesn't compile with the latest DMD 2.057head:

import std.math: poly;
enum p = poly(2.0, [-2, 3, 5]);
void main() {}


The error:
...\dmd2\src\phobos\std\math.d(3752): Error: asm statements cannot be interpreted at compile time
test.d(2):        called from here: poly(2L,[-2L,3L,5L])


The code of poly is something like this:


real poly(real x, const real[] A) pure {
    version (D_InlineAsm_X86) {
        version (Windows) {
            asm { // assembler by W. Bright
                mov     ECX,A[EBP];
                dec     ECX;
                lea     EDX,[ECX][ECX*8];
                add     EDX,ECX;
                add     EDX,A+4[EBP];
                fld     real ptr [EDX];
                jecxz   return_ST;
                fld     x[EBP];
                fxch    ST(1);
                align   4;
        L2:     fmul    ST,ST(1);
                fld     real ptr -10[EDX];
                sub     EDX,10;
                faddp   ST(1),ST;
                dec     ECX;
                jne     L2;
                fxch    ST(1);
                fstp    ST(0);
                align   4;
        return_ST:;
            }
        } else
            static assert(0);
    } else {
        sizediff_t i = A.length - 1;
        real r = A[i];
        while (--i >= 0) {
            r *= x;
            r += A[i];
        }
        return r;
    }
}


So there is code able to run at compile time, but D_InlineAsm_X86 is set at compile time too, despite CTFE is not able to run assembly code. In Phobos there are other similar cases where not-assembly fallback code is available, but it can't be used by CTFE.

Do you know how to improve this situation, avoiding messy code too?

Bye,
bearophile