[Issue 15956] New: Incorrect value inside enum using simd vectors, weird tym errors, and weird if(true) {} partial solution.

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=15956

          Issue ID: 15956
           Summary: Incorrect value inside enum using simd vectors, weird
                    tym errors, and weird if(true) {} partial solution.
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: lasssafin at gmail.com

Consider this piece of code:

import std.stdio : writeln;

struct vec4 {
    import core.simd;
    string toString() const {
        import std.format : format;
        return "%s\t%s\t%s\t%s".format(vec.array[0], vec.array[1],
vec.array[2], vec.array[3]);
    }

    float4 vec;

    this(in float[4] arr) {
        vec.array = arr;
    }
        // Switching the constructor out with this removes the if(true) error
and corrects the value inside the enum.
        /+
    this(in float4 arr) {
        vec = arr;
    }
        +/
}

void main(string[] _ARGS) {
    enum vec4 enm = [1, 0.4, 0.6, 1];
    enm.writeln;

    vec4 rntime = [1, 0.4, 0.6, 1];
    rntime.writeln;
    // When uncommented causes error: incompatible types for ((rntime.vec) ==
(vec4([1.00000F, 0.4F, 0.6F, 1.00000F]).vec)): '__vector(float[4])' and
'__vector(float[4])'
    // writeln(rntime == enm); Comparing only vec explicitly doesn't work
either.

    // When commented causes error:
    // tym = x1d
    // Internal error: backend/cgxmm.c 547
    if(true) {} // Condition can really be anything.
}

Output:
1    0    0    0 // enm
1    0.4    0.6    1 // rntime

Output with -O:
1    0.4    0.6    1 // enm
1    0.4    0.6    1 // rntime

As you can see, the value inside the enum is not the value one would expect
there to be. There is also the error in comparing the two struct and the weird
if(true) clause.

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