[Issue 3632] modify float is float to do a bitwise compare
https://issues.dlang.org/show_bug.cgi?id=3632 Dlang Bot changed: What|Removed |Added Status|REOPENED|RESOLVED Resolution|--- |FIXED --- Comment #39 from Dlang Bot --- dlang/dmd pull request #13780 "fix Issue 3632 - modify float is float to do a bitwise compare" was merged into master: - 6974a1e2185e29603329860ecfc85822bcfc9657 by Dennis Korpel: fix Issue 3632 - modify float is float to do a bitwise compare https://github.com/dlang/dmd/pull/13780 --
[Issue 3632] modify float is float to do a bitwise compare
https://issues.dlang.org/show_bug.cgi?id=3632 --- Comment #38 from Dlang Bot --- @dkorpel created dlang/dmd pull request #13780 "fix Issue 3632 - modify float is float to do a bitwise compare" fixing this issue: - fix Issue 3632 - modify float is float to do a bitwise compare update TOK & target fix xtest46 Change back to original ufcs test Update changes https://github.com/dlang/dmd/pull/13780 --
[Issue 3632] modify float is float to do a bitwise compare
https://issues.dlang.org/show_bug.cgi?id=3632 Nathan S. changed: What|Removed |Added Status|RESOLVED|REOPENED CC||n8sh.second...@hotmail.com Resolution|FIXED |--- --- Comment #37 from Nathan S. --- This was incorrectly marked fixed. `float is float` is still not a bitwise comparison. --- import std.math : isIdentical; assert(!isIdentical(float.nan, -float.nan)); // passes assert(float.nan is -float.nan); // also passes --- --
[Issue 3632] modify float is float to do a bitwise compare
https://issues.dlang.org/show_bug.cgi?id=3632 RazvanN changed: What|Removed |Added Status|REOPENED|RESOLVED CC||razvan.nitu1...@gmail.com Resolution|--- |FIXED --- Comment #36 from RazvanN --- Fixed by: https://github.com/dlang/dmd/pull/9897 --
[Issue 3632] modify float is float to do a bitwise compare
https://issues.dlang.org/show_bug.cgi?id=3632 --- Comment #35 from Dlang Bot --- @ibuclaw updated dlang/dmd pull request #7568 "fix Issue 3632 - modify float is float to do a bitwise compare" fixing this issue: - fix Issue 3632 - modify float is float to do a bitwise compare https://github.com/dlang/dmd/pull/7568 --
[Issue 3632] modify float is float to do a bitwise compare
https://issues.dlang.org/show_bug.cgi?id=3632 Daniel Kozak changed: What|Removed |Added CC||kozz...@gmail.com --- Comment #34 from Daniel Kozak --- *** Issue 8530 has been marked as a duplicate of this issue. *** --
[Issue 3632] modify float is float to do a bitwise compare
https://issues.dlang.org/show_bug.cgi?id=3632 Andrei Alexandrescu and...@erdani.com changed: What|Removed |Added Version|unspecified |D2 --
[Issue 3632] modify float is float to do a bitwise compare
https://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #32 from yebblies yebbl...@gmail.com 2013-11-15 18:02:51 EST --- *** Issue 11442 has been marked as a duplicate of this issue. *** -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
https://d.puremagic.com/issues/show_bug.cgi?id=3632
Denis Shelomovskij verylonglogin@gmail.com changed:
What|Removed |Added
CC||verylonglogin@gmail.com
--- Comment #29 from Denis Shelomovskij verylonglogin@gmail.com
2013-11-05 12:53:25 MSK ---
So currently we have this:
---
void main()
{
float f1, f2 = float.nan;
assert(f1 !is f2); // ok
import std.math;
assert(NaN(0) !is NaN(1)); // ok
assert(NaN(1) !is NaN(2)); // ok
}
static assert({
float f1, f2 = float.nan;
assert(f1 !is f2); // error, the only failing test
return 1;
}());
---
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[Issue 3632] modify float is float to do a bitwise compare
https://d.puremagic.com/issues/show_bug.cgi?id=3632
--- Comment #30 from Denis Shelomovskij verylonglogin@gmail.com
2013-11-05 13:02:09 MSK ---
Looks like we have bitwise comparison at runtime, but `f_is` generates some
long assembly code in contrast to `i_is`:
---
bool f_is(float f1, float f2)
{ return f1 is f2; }
bool i_is(int i1, int i2)
{ return i1 is i2; }
---
Can somebody explain what currently does `float is float` do in runtime?
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[Issue 3632] modify float is float to do a bitwise compare
https://d.puremagic.com/issues/show_bug.cgi?id=3632
--- Comment #31 from yebblies yebbl...@gmail.com 2013-11-05 21:20:15 EST ---
(In reply to comment #30)
Looks like we have bitwise comparison at runtime, but `f_is` generates some
long assembly code in contrast to `i_is`:
---
bool f_is(float f1, float f2)
{ return f1 is f2; }
bool i_is(int i1, int i2)
{ return i1 is i2; }
---
Can somebody explain what currently does `float is float` do in runtime?
Calls memcmp (
https://github.com/D-Programming-Language/dmd/pull/724/files#diff-6e3ab8a500e476994f345ede433811bbR2479
)
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[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #28 from yebblies yebbl...@gmail.com 2013-01-17 16:08:29 EST --- New (and hopefully last) pull https://github.com/D-Programming-Language/dmd/pull/1499 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #26 from github-bugzi...@puremagic.com 2012-04-27 15:06:20 PDT --- Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/f9c21c2a77e32d310c8cb9d6c23f517d410cbec6 Reintroduce the fix for issue 3632, without the dependency on fixing issue 1824. Revert the parts in clone.c that were commented out, so pull #387 can merge cleanly. https://github.com/D-Programming-Language/dmd/commit/5da38bd430246d82e06d5581bb15325094821ca5 Merge pull request #730 from yebblies/issue3632 Reintroduce the fix for issue 3632, without the dependency on fixing issue 1824. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #27 from Walter Bright bugzi...@digitalmars.com 2012-04-27 15:43:54 PDT --- Reverted because their tests failed. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #23 from github-bugzi...@puremagic.com 2012-02-17 16:40:35 PST --- Commit pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/b558967f56b3702557e5c70132e77dd05561f2e3 Merge pull request #724 from yebblies/issue3632 Issue 3632 - modify float is float to do a bitwise compare -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #24 from Walter Bright bugzi...@digitalmars.com 2012-02-17 17:22:43 PST --- change reverted - does not work -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #25 from yebblies yebbl...@gmail.com 2012-02-18 13:36:57 EST --- New pull to revert the revert. https://github.com/D-Programming-Language/dmd/pull/730 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #21 from bearophile_h...@eml.cc 2012-02-16 04:44:31 PST --- (In reply to comment #20) - I really believe that the advantages of 'is' always being a straight bitwise comparison outweigh the downsides. This is what I was asking in the closed down issue 3981 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #22 from yebblies yebbl...@gmail.com 2012-02-17 00:08:26 EST --- (In reply to comment #21) This is what I was asking in the closed down issue 3981 I know, that's why I closed issue 3981 with a comment saying that part was covered by this report... -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 yebblies yebbl...@gmail.com changed: What|Removed |Added Keywords||pull AssignedTo|nob...@puremagic.com|yebbl...@gmail.com --- Comment #20 from yebblies yebbl...@gmail.com 2012-02-16 17:07:55 EST --- New pull for this issue: https://github.com/D-Programming-Language/dmd/pull/724 Walter, please reconsider your position - I really believe that the advantages of 'is' always being a straight bitwise comparison outweigh the downsides. As you've pointed the inconsistency between how floats are handled with 'is' and when determining if template value parameters match, I've changed that too to make it consistent. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #19 from Steven Schveighoffer schvei...@yahoo.com 2011-07-18 06:37:46 PDT --- (In reply to comment #18) (In reply to comment #7) Reopening as the commit above will cause the following assert to fail: static assert(real.init !is real.nan); If they are not the same bit pattern, I think this is fine. is should be a bitwise compare. I don't know enough about floating point to know whether they are the same bit pattern. I think I misread the above. If the above assert fails, and they are different bit patterns, this is definitely a problem. Two different bit patterns should fail to compare as equal. == can do the intelligent standards-conforming thing, but 'is' should do bitwise comparison. If it doesn't, then you cannot use it as a tool to verify low-level manipulation (such as allocating memory with a pre-defined value) is working. And I don't see the point of using 'is' on floating points otherwise, it's misleading. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #14 from Don clugd...@yahoo.com.au 2011-06-28 01:08:25 PDT --- (In reply to comment #10) (In reply to comment #9) (In reply to comment #8) This is intended. All nans are regarded as the same (even signalling and non-signalling). So we have to use std.math.isIdentical() to tell apart floating point values on the base of the their bit patterns. Do you have any need for this? I use it all the time, mainly for distinguishing between +0.0 and -0.0 But I think this has perhaps not been understood in this discussion: bitwise compare doesn't just affect NaN, it also means that +0.0 !is -0.0. There definitely seems value in changing 'is' so that 'A is A' is true for any A. Note that any user-defined type can define == to always return false, so it isn't true that 'A is B' implies 'A==B', so we don't lose consistency in that way. But it's reasonable to argue that '+0.0 is -0.0' should return true, and if you do that, then 'NaN is NaN' should also return true, regardless of the payload. Related: I think almost no one uses the NaN payloads because (beside being a niche need) almost no language gives easy and explicit support to manage those payloads (while in std.math there are functions like getNaNPayload). I've been around numerics for 35 years now, and I've never seen a use for NaN payloads. I've never seen anyone even propose a use. Until then, I suspect supporting such would just cause problems. NaN payloads were used extensively in Apple's SANE, to distinguish different error types. Eg, http://doc.4d.com/4D-Language-Reference-11.6/Error-Codes/SANE-NaN-Errors-1-255.300-206143.en.html -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #15 from Walter Bright bugzi...@digitalmars.com 2011-06-28 02:17:47 PDT --- (In reply to comment #14) I use it all the time, mainly for distinguishing between +0.0 and -0.0 'is' does distinguish between +0 and -0. Just not -Nan and +Nan, nor the Nan payloads. But it's reasonable to argue that '+0.0 is -0.0' should return true, and if you do that, then 'NaN is NaN' should also return true, regardless of the payload. I believe those are entirely different situations. The sign of 0 has a mathematical meaning to fp arithmetic, the sign/payload of Nan does not. NaN payloads were used extensively in Apple's SANE, to distinguish different error types. Eg, http://doc.4d.com/4D-Language-Reference-11.6/Error-Codes/SANE-NaN-Errors-1-255.300-206143.en.html I didn't know that. But it's worth noting that SANE has been dropped. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #16 from Don clugd...@yahoo.com.au 2011-06-28 04:43:29 PDT --- (In reply to comment #15) (In reply to comment #14) I use it all the time, mainly for distinguishing between +0.0 and -0.0 'is' does distinguish between +0 and -0. Just not -Nan and +Nan, nor the Nan payloads. Then I don't understand the reasoning. I don't think the payload NaN behaviour is terribly important, but being able to do bitwise compare gives an _enormous_ speed benefit. Note that it isn't possible to create a NaN with a payload at compile time, so I don't think that the argument based on template behaviour is relevant -- as I see it, either behaviour is reasonable. But it's reasonable to argue that '+0.0 is -0.0' should return true, and if you do that, then 'NaN is NaN' should also return true, regardless of the payload. I believe those are entirely different situations. The sign of 0 has a mathematical meaning to fp arithmetic, the sign/payload of Nan does not. Yes, but my argument was the other way around: if you're going to special trouble with -0, you should deal with NaNs as well. But now, if you haven't given -0 special treatment, why slow down 'is' for the sake of the incredibly obscure NaN payload case? Why not just say, it does a bitwise compare, which is fast but may give unexpected answers in the case of negative zero and NaNs? -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
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--- Comment #17 from Steven Schveighoffer schvei...@yahoo.com 2011-06-28
04:56:43 PDT ---
(In reply to comment #11)
The use case I can remember being discussed is using 'v is float.init' to
determine if a floating point value is uninitialized or is a nan due to the
result of a calculation.
[snip]
Maybe Steven or Don have an opinion on this feature they asked for?
'isIdentical' seems to do a straight bitwise comparison.
Quite simply, the above (v is float.init) is my use case. In some parts of the
code, the runtime is responsible for default initializing data. I wanted to
verify that my code was properly initializing the data to T.init.
This is impossible without casting the value to a ubyte[] array to do a
comparison (and even then, it's not quite right, because you can have garbage
data in some cases).
But it makes no sense to me for is to ever do anything but a bitwise compare.
In other words, given any type T (and I mean any type T):
foo(T t)
{
assert(t is t);
}
should always pass. It makes no sense to me for is to do anything else -- it's
low-level bitwise comparison that bypasses any operators.
To make this true for every type *except* floating point types seems like a
huge inconsistency.
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[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #18 from Steven Schveighoffer schvei...@yahoo.com 2011-06-28 05:02:11 PDT --- (In reply to comment #7) Reopening as the commit above will cause the following assert to fail: static assert(real.init !is real.nan); If they are not the same bit pattern, I think this is fine. is should be a bitwise compare. I don't know enough about floating point to know whether they are the same bit pattern. In my understanding of floating point, this means that: if(x is typeof(x).nan) ... is not wise code -- it may fail if the exact nan bitpattern is different (my understanding is that nan has multiple representations). While it may be unintuitive, that is no fault of D -- floating point is sometimes very unintuitive. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 kenn...@gmail.com changed: What|Removed |Added Status|REOPENED|RESOLVED Resolution||FIXED --- Comment #6 from kenn...@gmail.com 2011-06-27 07:21:00 PDT --- https://github.com/D-Programming-Language/dmd/commit/32740 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 yebblies yebbl...@gmail.com changed: What|Removed |Added Status|RESOLVED|REOPENED Resolution|FIXED | --- Comment #7 from yebblies yebbl...@gmail.com 2011-06-27 08:19:40 PDT --- Reopening as the commit above will cause the following assert to fail: static assert(real.init !is real.nan); And the padding issue has only been fixed for the compile time evaluation, not runtime. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #8 from Walter Bright bugzi...@digitalmars.com 2011-06-27 11:32:17 PDT --- (In reply to comment #7) Reopening as the commit above will cause the following assert to fail: static assert(real.init !is real.nan); This is intended. All nans are regarded as the same (even signalling and non-signalling). And the padding issue has only been fixed for the compile time evaluation, not runtime. You're right. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #9 from bearophile_h...@eml.cc 2011-06-27 13:33:12 PDT --- (In reply to comment #8) This is intended. All nans are regarded as the same (even signalling and non-signalling). So we have to use std.math.isIdentical() to tell apart floating point values on the base of the their bit patterns. Related: I think almost no one uses the NaN payloads because (beside being a niche need) almost no language gives easy and explicit support to manage those payloads (while in std.math there are functions like getNaNPayload). -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #10 from Walter Bright bugzi...@digitalmars.com 2011-06-27 14:51:23 PDT --- (In reply to comment #9) (In reply to comment #8) This is intended. All nans are regarded as the same (even signalling and non-signalling). So we have to use std.math.isIdentical() to tell apart floating point values on the base of the their bit patterns. Do you have any need for this? Related: I think almost no one uses the NaN payloads because (beside being a niche need) almost no language gives easy and explicit support to manage those payloads (while in std.math there are functions like getNaNPayload). I've been around numerics for 35 years now, and I've never seen a use for NaN payloads. I've never seen anyone even propose a use. Until then, I suspect supporting such would just cause problems. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
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--- Comment #11 from yebblies yebbl...@gmail.com 2011-06-27 20:40:16 PDT ---
(In reply to comment #10)
I've been around numerics for 35 years now, and I've never seen a use for NaN
payloads. I've never seen anyone even propose a use. Until then, I suspect
supporting such would just cause problems.
This report has always been asking for a bitwise comparion, which is (as far as
I can tell) how every other type is treated by 'is'.
The use case I can remember being discussed is using 'v is float.init' to
determine if a floating point value is uninitialized or is a nan due to the
result of a calculation.
This seems to be the reason float.nan and float.init have different payloads in
the first place.
Currently this fails:
struct A { float f; }
A a;
A b;
b.f = float.nan;
assert((a is b) is (a.f is b.f));
Making 'is' for floating point types consistent with 'is' for other types seems
to me like a better move than introducing a new special case.
Maybe Steven or Don have an opinion on this feature they asked for?
'isIdentical' seems to do a straight bitwise comparison.
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[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #12 from Walter Bright bugzi...@digitalmars.com 2011-06-27 21:08:47 PDT --- (In reply to comment #11) Making 'is' for floating point types consistent with 'is' for other types seems to me like a better move than introducing a new special case. The current behavior matches template argument matching. Making it different from such will introduce all kinds of anomalous behavior. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 --- Comment #13 from yebblies yebbl...@gmail.com 2011-06-27 21:25:22 PDT --- (In reply to comment #12) The current behavior matches template argument matching. Making it different from such will introduce all kinds of anomalous behavior. Fair enough. I'm not sure which way is more useful, but they should definitely match. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 Walter Bright bugzi...@digitalmars.com changed: What|Removed |Added Status|NEW |RESOLVED CC||bugzi...@digitalmars.com Resolution||FIXED --- Comment #3 from Walter Bright bugzi...@digitalmars.com 2011-06-25 23:20:33 PDT --- https://github.com/D-Programming-Language/dmd/commit/0d93cf4333df6e167f9027eb1a4b0aa9a940ff19 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 bearophile_h...@eml.cc changed: What|Removed |Added CC||bearophile_h...@eml.cc --- Comment #4 from bearophile_h...@eml.cc 2011-06-26 00:49:51 PDT --- Do you know what's missing in the list of bug 3981 ? -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
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kenn...@gmail.com changed:
What|Removed |Added
Status|RESOLVED|REOPENED
CC||kenn...@gmail.com
Resolution|FIXED |
--- Comment #5 from kenn...@gmail.com 2011-06-26 01:37:29 PDT ---
This is *not yet fixed*. The current implementation in DMD
real_t v1 = e1-toReal();
real_t v2 = e2-toReal();
cmp = !memcmp(v1, v2, sizeof(real_t));
will not work, at least on OS X, because while 'real_t' ('long double') is only
a 80-bit floating point number (occupying 10 bytes), with alignment
'sizeof(real_t)' will take 16 bytes. The extra 6 bytes of paddings are often
filled with garbage. This makes even
4.0 is 4.0
to return 'false'.
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http://d.puremagic.com/issues/show_bug.cgi?id=3632 yebblies yebbl...@gmail.com changed: What|Removed |Added Keywords||patch CC||yebbl...@gmail.com --- Comment #2 from yebblies yebbl...@gmail.com 2011-06-14 23:50:06 PDT --- Possible implementation. https://github.com/D-Programming-Language/dmd/pull/126 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
[Issue 3632] modify float is float to do a bitwise compare
http://d.puremagic.com/issues/show_bug.cgi?id=3632 Don clugd...@yahoo.com.au changed: What|Removed |Added CC||clugd...@yahoo.com.au --- Comment #1 from Don clugd...@yahoo.com.au 2009-12-18 22:49:41 PST --- (In reply to comment #0) It was pointed out that Phobos has isIdentical, but that doesn't work with literals for some reason: float a; assert(isIdentical(a, float.init)) // fails! That's because of the recently discovered NaN bug; the code generated for uninitialized floats and doubles needs to change. It's not a problem with isIdentical. But it shouldn't be this hard. Why does 'is' do a bitwise compare for everything *except* floating point numbers? I propose that for floating point types, x is y be equivalent to a bitwise compare. It is easy to say in the spec x is y does a bitwise compare, which for all builtin types except for floating point types is equivalent to equality I think this would be a good idea. I've thought that several times myself. I created the isIdentical() function because I think there's a need for it. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email --- You are receiving this mail because: ---
