> /usr/local/linare-gcc-5.2/bin/gcc -S -O3 -march=armv8-a+lse test.c
>
> add_int:
> ldaddal w0, w0, [x1]
> add w2, w0, w0
> mov w0, w2
> ret
Am I going mad, or does this just return the contents of the memory
location * 2.
ldaddal w0, w0, [x1]
Returns the
Hi Yvan,
On 9 March 2016 at 13:22, Yvan Roux wrote:
> Hi Ed,
>
> On 9 March 2016 at 14:02, Edward Nevill wrote:
>> Hi,
>>
>>
>> Why the extra (unnecessary?) memory barrier?
>
> This is because Linaro gcc-5-branch is in sync with FSF gcc-5-branch
>
Hi,
I have been comparing the stock gcc 5.2 and the Linaro 5.2 (Linaro GCC
5.2-2015.11-1) and have noticed a difference with the __sync
intrinsics.
Here is the simple test case
--- cut here ---
int add_int(int add_value, int *dest)
{
return __sync_add_and_fetch(dest, add_value);
}
--- cut here
On Wed, 2016-03-02 at 14:25 +, Renato Golin wrote:
> On 2 March 2016 at 11:35, Edward Nevill wrote:
> > cmp x2, 8 <<< (1)
> > (1) If count as a 64 bit unsigned is <= 8 then it is probably still <= 8 as
> > a 32 bit unsigned.
>
&g
Hi,
I have just switched to gcc 5.2 from 4.9.2 and the code quality does seem to
have improved significantly. For example, it now seems much better at using
ldp/stp and it seems to has stopped gratuitous use of the SIMD registers.
However, I still have a few whinges:-)
See attached copy.c / co
Hi,
I did some tests on the following function
--- CUT HERE ---
int fibo(int n)
{
if (n < 2) return 1;
return (fibo(n-2) + fibo(n-1));
}
--- CUT HERE ---
and I discovered that it is faster -O2 than -O3. This is with gcc 4.9.2.
Looking at the disassembly I see it is using FP registers to hol
Hi,
I have being trying to persuade gcc to generate the ldp instruction without
success. I have tried many combinations, below is an example.
--- cut here ---
#define LDP(x,y,p) { \
struct vec { long x, y; } data; \
data = *(struct vec *)p; p += 2; \
x = data.x; y = data.
Hi,
I am trying to port the Boost.Context library (from www.boost.org) to aarch64
gcc and have come across a gnarly problem.
Boost.Context essentially does co-routine style context switching. It has a
structure f_context which it uses to save and restore contexts. The structure
f_context conta
