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Re: [PATCH] C undefined behavior fix
- From: dewar at gnat dot com
- To: dewar at gnat dot com, mrs at windriver dot com, paulus at samba dot org
- Cc: gcc at gcc dot gnu dot org, linux-kernel at vger dot kernel dot org,trini at kernel dot crashing dot org, velco at fadata dot bg
- Date: Sun, 6 Jan 2002 14:29:01 -0500 (EST)
- Subject: Re: [PATCH] C undefined behavior fix
<<? Do you have an example where this fails? Do you not consider it a
bug? Now, I would place a fair amount of buren on the compiler to get
it right, though, this isn't absolute. For example, eieieio or
>>
I don't see the obligation on the compiler here. For instance spupose
you are on an architecture where a word read is faster than a byte read.
Let's make it specific, suppose you are on a 386 and the item is 16-bits.
Now it is quicker to read 32-bits, because no prefix is required. Do you
see anything in the C standard (or the Ada standard :-) which requires a
16-bit read here? I don't, but perhaps I am missing something.
Now if you are saying that this is a reasonable expectation, nothing to do
with the standard, then that's another matter, but my example of a tradeoff
with efficiency is an interesting one.