Structs in unittest / functions shouldn't have frame pointer unless necessary

[dlangBugzillaToGithub]

hsteoh reported this on 2013-07-09T11:21:21Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=10585

Description

CODE:

------snip------
import std.stdio;

void listMembers(T)() {
        writefln("Size of %s is %d", T.stringof, T.sizeof);
        foreach (field; __traits(allMembers, T)) {
                writefln("\t%s", field);
        }
}

void main() {
        int y=1;
        
        struct S1 {
                int x;
        }
        static struct S2 {
                int x;
                bool opEquals() { return true; }
        }
        struct S3 {
                int x;
                bool opEquals() { return true; }
        }
        struct S4 {
                int x;
                bool opEquals() { return y==1; }
        }
        
        listMembers!S1();
        listMembers!S2();
        listMembers!S3();
        listMembers!S4();
}
------snip------

OUTPUT:
------snip------
Size of S1 is 4
        x
Size of S2 is 4
        x
        opEquals
Size of S3 is 16
        x
        opEquals
        this
Size of S4 is 16
        x
        opEquals
        this
------snip------

S3 is identical to S2 (except for the 'static' qualifier); DMD should not insert the frame pointer since it's not needed.

According to TDPL, the frame pointer is only inserted where needed.