RE: [sv-ec] Re: [sv-bc] Musings on array assignment compatibility

From: Bresticker, Shalom <shalom.bresticker_at_.....>
Date: Wed Jun 03 2009 - 22:54:14 PDT
Hi, Greg,

Ooops.  Sorry.  I meant 2380. The one that relaxes the assignment compatibility definition for packed elements of unpacked arrays - going from equivalent to assignment compatible.
[SB] For the record, as Jonathan pointed out, 1447 was the change that relaxed that requirement, possibly inadvertently, after 1800 had strengthened it from SV 3.1a.

I was thinking of 1364-2005 section 5.6, which says:
5.6 Assignments and truncation
If the width of the right-hand expression is larger than the width of the left-hand side in an assignment, the
MSBs of the right-hand expression will always be discarded to match the size of the left-hand side.
Implementations are not required to warn or report any errors related to assignment size mismatch or
truncation. Truncating the sign bit of a signed expression may change the sign of the result.

[SB] Thanks, I missed that. P1800-2009 modifies that statement to say, "Implementations can, but are not required to, warn or report any errors related to assignment size mismatch or truncation."

I suppose I'm exaggerating to say that "not required to warn" encourages vendors to offer a warning.
I still think 1364 planted this seed of an idea.
Would the assignment compatibility change (2380) be more palatable if a warning about size (or bit value) change was required?

[SB] I would strongly oppose that. (You see? I'm not blindly in favor of warnings...)

Thanks,
Shalom
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Received on Wed Jun 3 22:56:26 2009

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