[Issue 13152] [REG2.064.2] Compiler high cpu usage and never ends

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13152

Vladimir Panteleev <thecybershadow at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |thecybershadow at gmail.com
            Summary|Compiler high cpu usage and |[REG2.064.2] Compiler high
                   |never ends                  |cpu usage and never ends

--- Comment #2 from Vladimir Panteleev <thecybershadow at gmail.com> ---
Domingo, can you try removing "public" from the imports in each module? I think
that's what's causing the slowdown.

I can reproduce the problem (and arrive at the same bisect result) with the
following synthetic test case:

////// a.d /////
public import a;
public import b;
.....
public import y;
public import z;
////////////////

Then copy a.d to b.d, c.d, ..., z.d.

You can use the following program to generate the test files:

///////////////////// gen.d ////////////////////
import std.stdio;

enum last = 'z';

void main()
{
    for (char c = 'a'; c<=last; c++)
    {
        auto f = File(c ~ ".d", "w");
        for (char c2 = 'a'; c2<=last; c2++)
            f.writefln("public import %s;", c2);
    }
}
////////////////////////////////////////////////

Running `dmd a.d` will take a very long time.

Introduced in https://github.com/D-Programming-Language/dmd/pull/2448 (between
2.063 and 2.064.2).

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