RE: GCC optimizes integer overflow: bug or feature?

[Dave Korn]

On 22 December 2006 00:59, Denis Vlasenko wrote:


> Or this, absolutely typical C code. i386 arch can compare
> 16 bits at a time here (luckily, no alighment worries on this arch):

  Whaddaya mean, no alignment worries?  Misaligned accesses *kill* your
performance!

  I know this doesn't affect correctness, but the coder might well have known
that the pointer is unaligned and written two separate byte-sized accesses on
purpose; volatile isn't the answer because it's too extreme, there's nothing
wrong with caching these values in registers and they don't spontaneously
change on us.

    cheers,
      DaveK
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