This was caused (or perhaps abetted by) the representation of EQ
as NE ^ 1. With the subsequent truncation and zero-extend, I
think combine reached its insn limit of 3 before seeing everything
it needed to see.
This can be 4 now, if you tweak the initial heuristic.
--
Eric Botcazou
Richard Henderson wrote:
On 08/07/2012 10:02 AM, Ulrich Weigand wrote:
The following patch changes the builtin expander to pass a MEM oldval
as-is to the back-end expander, so that the back-end can move the
store to before the CC operation. With that patch I'm also seeing
all the IPMs
Richard Henderson wrote:
On 08/06/2012 11:34 AM, Ulrich Weigand wrote:
There is one particular inefficiency I have noticed. This code:
if (!__atomic_compare_exchange_n (v, expected, max, 0 , 0, 0))
abort ();
from atomic-compare-exchange-3.c gets compiled into:
l
On 08/07/2012 10:02 AM, Ulrich Weigand wrote:
The following patch changes the builtin expander to pass a MEM oldval
as-is to the back-end expander, so that the back-end can move the
store to before the CC operation. With that patch I'm also seeing
all the IPMs disappear.
...
What do you
On 08/06/2012 11:34 AM, Ulrich Weigand wrote:
There is one particular inefficiency I have noticed. This code:
if (!__atomic_compare_exchange_n (v, expected, max, 0 , 0, 0))
abort ();
from atomic-compare-exchange-3.c gets compiled into:
l %r3,0(%r2)
larl
