[Issue 21641] New: std.format: %g produces in rare circumstances inconsistent result

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21641

          Issue ID: 21641
           Summary: std.format: %g produces in rare circumstances
                    inconsistent result
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: minor
          Priority: P1
         Component: phobos
          Assignee: nobody at puremagic.com
          Reporter: bugzilla at bernis-buecher.de

import std.stdio;

void main()
{
    float a = -999999.8125;
    writefln!"%#.1g"(a);
    writefln!"%#.2g"(a);
    writefln!"%#.3g"(a);
    writefln!"%#.4g"(a);
    writefln!"%#.5g"(a);
    writefln!"%#.6g"(a);
    writefln!"%#.7g"(a);
    writefln!"%#.8g"(a);
    writefln!"%#.9g"(a);
}

produces:

-1.e+06
-1.0e+06
-1.00e+06
-1.000e+06
-1.0000e+06
-1.e+06
-999999.8
-999999.81
-999999.812

The sixth line is inconsistent, should be -1.00000e+06.

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