question oh macros and gcc's intelligence

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* question oh macros and gcc's intelligence
@ 2011-03-17  7:48 Oliver Neukum
  2011-03-17  9:06 ` Al Viro
  0 siblings, 1 reply; 2+ messages in thread
From: Oliver Neukum @ 2011-03-17  7:48 UTC (permalink / raw)
  To: linux-kernel

Hi,

if I write:

if (le16_to_cpu(p) == CONST) a();

is gcc smart enough to convert CONST to le16 and do
a simple comparison?

	Regards
		Oliver

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: question oh macros and gcc's intelligence
  2011-03-17  7:48 question oh macros and gcc's intelligence Oliver Neukum
@ 2011-03-17  9:06 ` Al Viro
  0 siblings, 0 replies; 2+ messages in thread
From: Al Viro @ 2011-03-17  9:06 UTC (permalink / raw)
  To: Oliver Neukum; +Cc: linux-kernel

On Thu, Mar 17, 2011 at 08:48:57AM +0100, Oliver Neukum wrote:
> Hi,
> 
> if I write:
> 
> if (le16_to_cpu(p) == CONST) a();
> 
> is gcc smart enough to convert CONST to le16 and do
> a simple comparison?

On little-endian - certainly, on big-endian - forget it.
	if (p == cpu_to_le16(CONST))
would obviously work on any architecture and yes, it would be a comparison
with compile-time constant.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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