[cfe-commits] implicit sign/bitwidth conversions during array indexing?

Eli Friedman eli.friedman at gmail.com
Fri Nov 14 11:00:32 PST 2008

On Thu, Nov 13, 2008 at 6:43 PM, Zhongxing Xu <xuzhongxing at gmail.com> wrote:
> Is this the rule:
>  - if the bitwidth of E2 is the same as the pointer, do the arithmetic.
>  - if the bitwidth of E2 is different from the pointer, trunc or ext it to
> the same width of the pointer. Signed-ness affects the ext operation. Then
> do the arithmetic.

The rule is conceptually the following: "Do the arithmetic exactly; if
there's overflow, the result is undefined."

Your rules are equivalent for the defined cases, though.


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