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[Bug middle-end/25125] [4.1/4.2 Regression] (short) ((int)(unsigned short) + (int)) is done in the wrong type
- From: "kazu at codesourcery dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 19 Dec 2005 18:38:57 -0000
- Subject: [Bug middle-end/25125] [4.1/4.2 Regression] (short) ((int)(unsigned short) + (int)) is done in the wrong type
- References: <bug-25125-6528@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from kazu at codesourcery dot com 2005-12-19 18:38 -------
Subject: Re: [4.1/4.2 Regression] (short) ((int)(unsigned
short) + (int)) is done in the wrong type
Hi Mark,
> (Why should we get 1? Upon entry to f, a will be 1, since 32769 will be
> reduced modulo 2^16. Then, b will be 1 - 32768, or -32767. I don't see why
> that should be converted to 1 -- but I certainly don't see why it should be
> 32768 either.)
>
> In any case, wrong-code: P1.
First, 32769 will be reduced to -32767.
(int) -32767 + -(int)32768 = -65535.
If we take the lowest 16 bits of -65535, we get 1, and that's what f should be
returning.
Kazu Hirata
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25125