https://issues.dlang.org/show_bug.cgi?id=20451
Issue ID: 20451
Summary: comparing identical floating points does not work on
Win32 and FreeBSD32.
Product: D
Version: D2
Hardware: Other
OS: Windows
Status: NEW
Severity: normal
Priority: P1
Component: dmd
Assignee: [email protected]
Reporter: [email protected]
Evolving from issue 5628:
---
import std.math;
import std.stdio;
void main()
{
immutable real x = 46;
immutable float xf = x;
immutable double xd = x;
immutable short neg2 = -2;
immutable long neg8 = -8;
writefln!"%.70f"(pow(xd, neg2));
writefln!"%.70f"(cast(double) (1 / (x * x)));
writefln!"%.70f"(pow(xf, neg8));
writefln!"%.70f"(cast(float) (1 / ((x * x) * (x * x) * (x * x) * (x *
x))))$
assert(pow(xd, neg2) == cast(double) (1 / (x * x))); // line 7902
assert(pow(xf, neg8) == cast(float) (1 / ((x * x) * (x * x) * (x * x) * (x
$
}
---
I ran essentially this program in the testsuite and got:
0.0004725897920604915061933148923145608932827599346637725830078125000000
0.0004725897920604915061933148923145608932827599346637725830078125000000
0.0000000000000498812518796420273359260022516536992043256759643554687500
0.0000000000000498812518796420273359260022516536992043256759643554687500
****** FAIL release32 std.math
core.exception.AssertError@std/math.d(7902): unittest failure
This is the output of FreeBSD-32. On Win32 the result was essentially the same.
All others worked. If this program doesn't work (I have no direct access to any
of the two OSs), go to std.math, look for the test containing "neg8" and put
the last 6 lines of the unittest there (and remove @safe etc. from the test).
Then let the testsuite run.
And I'm pretty aware, that one should not compare floating point numbers with
== due to rounding issues. But the output above shows, that the numbers have
identical bit patterns and they are also of identical type. That should not
even fail with floating point numbers.
--
