On 02/04/2019 01.55, Sultan Alsawaf wrote:
> On Mon, Apr 01, 2019 at 10:43:13PM +0200, Rasmus Villemoes wrote:
>> No. First, these are concerns for all arches. Second, if you can find
>> some particular place where string parsing/matching is in any way
>> performance relevant and not just done
On Mon, Apr 01, 2019 at 10:43:13PM +0200, Rasmus Villemoes wrote:
> Consider your patch replacing !strcmp(buf, "123") by !memcmp(buf, "123",
> 4). buf is known to point to a nul-terminated string. But it may point
> at, say, the second-last byte in a page, with the last byte in that page
> being a
On 30/03/2019 23.59, Sultan Alsawaf wrote:
> How can the memcmps cross a page boundary when memcmp itself will
> only read in large buffers of data at word boundaries?
Consider your patch replacing !strcmp(buf, "123") by !memcmp(buf, "123",
4). buf is known to point to a nul-terminated string.
On Mon, Mar 25, 2019 at 10:24:00PM +0100, Rasmus Villemoes wrote:
> What I'm worried about is your patch changing every single strcmp(,
> "literal") into a memcmp, with absolutely no way of knowing or checking
> anything about the other buffer. And actually, it doesn't have to be a
> BE arch with
On 24/03/2019 23.32, Sultan Alsawaf wrote:
> On Sun, Mar 24, 2019 at 10:17:49PM +0100, Rasmus Villemoes wrote:
>> gcc already knows the semantics of these functions and can optimize
>> accordingly. E.g. for strcpy() of a literal to a buffer, gcc readily
>> compiles
>
> The example you gave
On Sun, Mar 24, 2019 at 10:17:49PM +0100, Rasmus Villemoes wrote:
> gcc already knows the semantics of these functions and can optimize
> accordingly. E.g. for strcpy() of a literal to a buffer, gcc readily
> compiles
The example you gave appears to get optimized accordingly, but there are
On 24/03/2019 03.24, Sultan Alsawaf wrote:
> I messed up the return value for strcat in the first patch. Here's a fixed
> version, ready for some scathing reviews.
>
> From: Sultan Alsawaf
>
> When strcpy, strcat, and strcmp are used with a literal string, they can
> be optimized to memcpy or
On Sat, Mar 23, 2019 at 07:24:06PM -0700, Sultan Alsawaf wrote:
> I messed up the return value for strcat in the first patch. Here's a fixed
> version, ready for some scathing reviews.
>
> From: Sultan Alsawaf
>
> When strcpy, strcat, and strcmp are used with a literal string, they can
> be
I messed up the return value for strcat in the first patch. Here's a fixed
version, ready for some scathing reviews.
From: Sultan Alsawaf
When strcpy, strcat, and strcmp are used with a literal string, they can
be optimized to memcpy or memcmp calls. These alternatives are faster
since knowing
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