digitalmars.D.bugs - [Issue 1989] New: opEquals should return bool
- d-bugmail puremagic.com Apr 12 2008
- d-bugmail puremagic.com Apr 14 2008
- d-bugmail puremagic.com Apr 14 2008
- d-bugmail puremagic.com May 22 2008
- d-bugmail puremagic.com May 26 2008
- d-bugmail puremagic.com Jun 10 2008
- d-bugmail puremagic.com Sep 03 2008
- d-bugmail puremagic.com Sep 03 2008
- d-bugmail puremagic.com Sep 03 2008
- d-bugmail puremagic.com Sep 10 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 Summary: opEquals should return bool Product: D Version: 1.028 Platform: Other OS/Version: All Status: NEW Severity: normal Priority: P2 Component: DMD AssignedTo: bugzilla digitalmars.com ReportedBy: larsivar igesund.net This has been requested many times on the NG (and I apologize if a bugzilla entry exists, I could not find it), but has been brushed off with bogus and/or outdated reasoning. Instead the int return cause confusion and problems, for instance in template code using bool returning predicates where opEquals won't work although doing the semantically same thing. --
Apr 12 2008
d-bugmail puremagic.com http://d.puremagic.com/issues/show_bug.cgi?id=1989 ------- Comment #1 from gide nwawudu.com 2008-04-14 05:45 -------..but has been brushed off with bogus and/or outdated reasoning.
opEquals returning bool makes sense, performance was given as the reason for not changing things. See, http://www.digitalmars.com/d/archives/digitalmars/D/bugs/7933.html. --
Apr 14 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 ------- Comment #2 from larsivar igesund.net 2008-04-14 05:54 ------- (In reply to comment #1)..but has been brushed off with bogus and/or outdated reasoning.
opEquals returning bool makes sense, performance was given as the reason for not changing things. See, http://www.digitalmars.com/d/archives/digitalmars/D/bugs/7933.html.
This was discussed in the main newsgroup at a later date, and it was shown there that the performance reasoning was outdated. Unfortunately I don't have the link handy. --
Apr 14 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 ------- Comment #3 from terranium yandex.ru 2008-05-22 07:33 ------- here's the link: http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/25112.PDF :) int areEqual(int op1, int op2) { return op1-op2; } mov eax, [ebp+8] sub eax, [ebp+12] ; now eax contains 0 if they're equal, this is not what we want. ; negate it setz al ; 3 bytes, 1 cycle and eax, 1 ; 3 bytes, 1 cycle ret 8 using bool: mov eax, [ebp+8] cmp eax, [ebp+12] sete al ; 3 bytes, 1 cycle ret 8 I can't see efficiency of int used instead of bool. --
May 22 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 matti.niemenmaa+dbugzilla iki.fi changed: What |Removed |Added ---------------------------------------------------------------------------- Platform|Other |All Version|1.028 |0.163 ------- Comment #4 from matti.niemenmaa+dbugzilla iki.fi 2008-05-26 09:50 ------- Here's a post which further ridicules the performance argument: http://yarchive.net/comp/fastest_int.html A quote from the summary: 'the bottom line of all of this, is that "fastest" is a very slippery metric, and no one should ever expect that any one size is uniformly faster, because it hardly ever is'. I set the version to 0.163 based on Issue 288, although maybe this should just be considered a duplicate of it? --
May 26 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 ------- Comment #5 from brunodomedeiros+bugz gmail.com 2008-06-10 10:59 ------- (In reply to comment #2)(In reply to comment #1)..but has been brushed off with bogus and/or outdated reasoning.
opEquals returning bool makes sense, performance was given as the reason for not changing things. See, http://www.digitalmars.com/d/archives/digitalmars/D/bugs/7933.html.
there that the performance reasoning was outdated. Unfortunately I don't have the link handy.
Lol, the NG thread where the performance argument was debunked is that very same one Gide posted ;), see this post: http://www.digitalmars.com/d/archives/digitalmars/D/bugs/7933.html#N8005 --
Jun 10 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 gide nwawudu.com changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |DUPLICATE ------- Comment #6 from gide nwawudu.com 2008-09-03 08:08 ------- *** This bug has been marked as a duplicate of 288 *** --
Sep 03 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 smjg iname.com changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |smjg iname.com ------- Comment #7 from smjg iname.com 2008-09-03 09:02 ------- (In reply to comment #2)This was discussed in the main newsgroup at a later date, and it was shown there that the performance reasoning was outdated. Unfortunately I don't have the link handy.
Was there any "performance reasoning" for this particular case that was even valid in the first place? (In reply to comment #3)int areEqual(int op1, int op2) { return op1-op2; }
Uh, that doesn't even work. Try it for yourself and see. Yet more reasons that opEquals should return bool: http://tinyurl.com/6p93a9 --
Sep 03 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 ------- Comment #8 from spam extrawurst.org 2008-09-03 09:41 ------- this is already fixed since 2.016 --
Sep 03 2008
http://d.puremagic.com/issues/show_bug.cgi?id=1989 ------- Comment #9 from terranium yandex.ru 2008-09-10 09:40 ------- (In reply to comment #7)int areEqual(int op1, int op2) { return op1-op2; }
Uh, that doesn't even work. Try it for yourself and see.
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Sep 10 2008