C#•2y ago

Float (signed) number comparisons compiled to unsigned version of instruction

Why does

    public bool lteq(float a, float b) {
        return a <= b;
    }

    public bool lteq(float a, float b) {
        return a <= b;
    }

    public bool lteq(float a, float b) {
        return a <= b;
    }

    public bool lteq(float a, float b) {
        return a <= b;
    }

compile to

        IL_0000: ldarg.1
        IL_0001: ldarg.2
        IL_0002: cgt.un
        IL_0004: ldc.i4.0
        IL_0005: ceq
        IL_0007: ret

        IL_0000: ldarg.1
        IL_0001: ldarg.2
        IL_0002: cgt.un
        IL_0004: ldc.i4.0
        IL_0005: ceq
        IL_0007: ret

        IL_0000: ldarg.1
        IL_0001: ldarg.2
        IL_0002: cgt.un
        IL_0004: ldc.i4.0
        IL_0005: ceq
        IL_0007: ret

        IL_0000: ldarg.1
        IL_0001: ldarg.2
        IL_0002: cgt.un
        IL_0004: ldc.i4.0
        IL_0005: ceq
        IL_0007: ret

whereas

    public bool not(float a, float b) {
        return !(a > b);
    }

    public bool not(float a, float b) {
        return !(a > b);
    }

    public bool not(float a, float b) {
        return !(a > b);
    }

    public bool not(float a, float b) {
        return !(a > b);
    }

compiles to the same thing but with

cgt

cgt

cgt

cgt instead of

cgt.un

cgt.un

cgt.un

cgt.un? Are these two expressions not equivalent? I'm also confused why it's using

.un

.un

.un

C#/VB/F# compiler playground.