http://d.puremagic.com/issues/show_bug.cgi?id=10018

           Summary: Value range propagation for immutable variables
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: lio+bugzilla@lunesu.com


--- Comment #0 from Lionello Lunesu <lio+bugzilla@lunesu.com> 2013-05-02 11:39:08 PDT ---
immutable int i = 1;    //range from initializer does not propagate

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--- Comment #1 from Lionello Lunesu <lio+bugzilla@lunesu.com> 2013-05-02 12:32:38 PDT ---
https://github.com/D-Programming-Language/dmd/pull/1955

Not sure how to test this. There's no [portable] way of testing whether a range is being propagated, is there?

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Andrej Mitrovic <andrej.mitrovich@gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |andrej.mitrovich@gmail.com


--- Comment #2 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2013-05-02 12:33:18 PDT ---
I don't understand the bug, what's the issue here?

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--- Comment #3 from Lionello Lunesu <lio+bugzilla@lunesu.com> 2013-05-02 17:35:02 PDT ---
(In reply to comment #2)
> I don't understand the bug, what's the issue here?

Any calculation with 'i' that uses VRP get the full int range, not the constant 1. The same holds for 'const int'.

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Lionello Lunesu <lio+bugzilla@lunesu.com> changed:

           What    |Removed                     |Added
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           Priority|P2                          |P4


--- Comment #4 from Lionello Lunesu <lio+bugzilla@lunesu.com> 2013-05-02 18:16:16 PDT ---
Degrading to P4, since in many cases, calling optimize() on the Expression
before doing getIntRange() will in fact return the constant range.

Not closing until I've identified that indeed implementing VarExp::getIntRange() would NOT have any effect.

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bearophile_hugs@eml.cc changed:

           What    |Removed                     |Added
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                 CC|                            |bearophile_hugs@eml.cc


--- Comment #5 from bearophile_hugs@eml.cc 2013-07-10 04:43:10 PDT ---
(In reply to comment #1)
> https://github.com/D-Programming-Language/dmd/pull/1955

This is a good improvement for D. I hope you will fix and reopen your patch.

But I think this issue should be tagged as "enhancement".

See also Issue 10594  for an "improvement" of this idea.

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--- Comment #6 from bearophile_hugs@eml.cc 2013-07-20 13:58:03 PDT ---
Se also Issue 10685 , Issue 10615 , Issue 10594

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