YACCWVT (yet another compiler crash with vector types)

[mleise]

In the following code LDC is special as it is the only compiler of the three that crashed on all variants and even goes into infinite loop, ignoring the assert that stops the others in time. (Upstream report: http://d.puremagic.com/issues/show_bug.cgi?id=10518)

import core.simd;
import std.stdio;

version (DigitalMars) { enum isDMD = true;  enum isGDC = false; enum isLDC = false; }
else version (GNU)    { enum isDMD = false; enum isGDC = true;  enum isLDC = false; }
else version (LDC)    { enum isDMD = false; enum isGDC = false; enum isLDC = true;  }

void main()
{
    static if (!isLDC) {
        // ldc: Error: expression 'cast(immutable(__vector(ubyte[16LU])))cast(ubyte)123u' is not a constant
        static immutable ubyte16 vec1 = 123;
        writeln(vec1.array);
    }

    static if (!isDMD && !isLDC && !isGDC) {
        // dmd: init.c:660: virtual Expression* ArrayInitializer::toExpression(Type*): Assertion `0' failed.
        // gdc: init.c:615: virtual Expression* ArrayInitializer::toExpression(): Assertion `0' failed.
        // ldc: infinite loop
        static immutable ubyte16 vec2 = [123,123,123,123,123,123,123,123,123,123,123,123,123,123,123,123];
        writeln(vec2.array);
    }
}

I could define a constant like this: "enum ubyte16 SIMDConstant = value;" and GDC will optimize that case to be as fast as a static variable, but unfortunately in LDC my code becomes 4x slower this way, similar to the negative effects on having a long enum array or string.

[redstar]

I can confirm the first error (LDC head and LLVM 3.4 trunk).

In the second case the assertion error is triggered for me, too. Do you use an optimized build of ldc?

[mleise]

I just use the default build generated by cmake.
But its good to know that in theory it works.

[redstar]

The first error is fixed with commit a2f7246.

[redstar]

Finally fixed in 0.13.0.

[mleise]

Amen :)