As of DMD 2.063.2 it looks to me like inline assembly language
blocks are not usable in compile-time code. For example, the
following code
void main() {
enum a = abc();
}
ulong abc() {
asm { mov RAX,1; }
return 1;
}
will produce the error "Error: asm statements cannot be
interpreted at compile time".
Are there plans to eventually support the use of asm blocks in
CTFE?
If it were possible then I could use such a function in a static
if test. What I am looking to do is use a function that calls
CPUID (etc.) in a static if statement to determine which code to
generate, somewhat like the following.
bool isAVXPossible() { asm { ... use CPUID, etc. ... } }
void foo() {
static if(isAVXPossible()) {
asm { ... generate AVX version ... }
else {
asm { ... generate non AVX version ... }
}
}
I cannot use version(D_SIMD) because I need some more specificity
in the versioning. Similarly, version(X86) and version(X86_64)
are convenient but I would like to be more exact. Also, I tried
the functionality in core.cpuid but it also seems only able to
execute at run-time. When trying to use it in a static if
statement I get the error "Error: static variable xfeatures
cannot be read at compile time".
Any ideas on how to implement isAVXPossible() and its related
functionality without using a runtime test are appreciated.
Thanks
Joseph
