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Re: GCC optimizes integer overflow: bug or feature?
From: |
Gabriel Dos Reis |
Subject: |
Re: GCC optimizes integer overflow: bug or feature? |
Date: |
22 Dec 2006 03:47:58 +0100 |
Paul Eggert <address@hidden> writes:
| Ian Lance Taylor <address@hidden> writes:
|
| > We could disable VRP's assumptions about signed overflow. I don't
| > know what else we could do to fix this case. I don't even know how we
| > could issue a useful warning. Perhaps there is a way.
|
| It is a knotty problem. Thanks for thinking about it.
|
| I'm Handwaving with a capital H here, but one possibility is
| for plain -O2 to keep VRP, but disable its assumption about
| signed overflow when attempting to optimize away a
| comparison that comes directly from the user's code (as
| opposed to a comparison coming from subscript checking and
| the like).
If that is workable, it would be a good compromise.
-- Gaby
- Re: GCC optimizes integer overflow: bug or feature?, (continued)
- Re: GCC optimizes integer overflow: bug or feature?, Rask Ingemann Lambertsen, 2006/12/23
- Re: GCC optimizes integer overflow: bug or feature?, Gabriel Dos Reis, 2006/12/20
- Re: GCC optimizes integer overflow: bug or feature?, Robert Dewar, 2006/12/20
- Message not available
- Re: GCC optimizes integer overflow: bug or feature?, Paolo Bonzini, 2006/12/21
- Re: GCC optimizes integer overflow: bug or feature?, Paul Eggert, 2006/12/21
- Re: GCC optimizes integer overflow: bug or feature?, Joseph S. Myers, 2006/12/21
- Re: GCC optimizes integer overflow: bug or feature?, Paul Eggert, 2006/12/21
- Re: GCC optimizes integer overflow: bug or feature?, Ian Lance Taylor, 2006/12/21
- Re: GCC optimizes integer overflow: bug or feature?, Joseph S. Myers, 2006/12/21
- Re: GCC optimizes integer overflow: bug or feature?, Paul Eggert, 2006/12/21
- Re: GCC optimizes integer overflow: bug or feature?,
Gabriel Dos Reis <=
- Re: GCC optimizes integer overflow: bug or feature?, Paolo Bonzini, 2006/12/22
- Re: GCC optimizes integer overflow: bug or feature?, Paolo Bonzini, 2006/12/22
- Re: GCC optimizes integer overflow: bug or feature?, Paul Eggert, 2006/12/29
- Message not available
- Re: GCC optimizes integer overflow: bug or feature?, Toon Moene, 2006/12/27
- Re: GCC optimizes integer overflow: bug or feature?, Joe Buck, 2006/12/20
- Re: GCC optimizes integer overflow: bug or feature?, Andrew Haley, 2006/12/20
- Re: GCC optimizes integer overflow: bug or feature?, Gabriel Dos Reis, 2006/12/20
- RE: GCC optimizes integer overflow: bug or feature?, Dave Korn, 2006/12/20
- Re: GCC optimizes integer overflow: bug or feature?, Dorit Nuzman, 2006/12/20
- Re: GCC optimizes integer overflow: bug or feature?, Andrew Haley, 2006/12/19