On Thu, 2007-01-18 at 12:44 +0530, pranav bhandarkar wrote:
On 1/17/07, Mircea Namolaru [EMAIL PROTECTED] wrote:
Thanks. Another question I have is that, in this case, will the
following
http://gcc.gnu.org/wiki/Sign_Extension_Removal
help in removal of the sign / zero extension ?
On Thursday 18 January 2007 09:31, Jeffrey Law wrote:
I haven't followed this thread that closely, but it seems to me this
could be done in the propagation engine.
Basically we keep track of the known zero, sign bit copies and known
nonzero bits for SSA names, then propagate them in the
On Thu, 2007-01-18 at 09:41 +0100, Steven Bosscher wrote:
There appear to be more bit operations in RTL, so perhaps it is a
better idea to implement a known-bits propagation pass for RTL, with
the new dataflow engine.
If that's the case then most of the opportunities are appearing due to
Basically we keep track of the known zero, sign bit copies and known
nonzero bits for SSA names, then propagate them in the obvious ways.
Basically replicating a lot of what combine cse do in this area,
but at the tree level. It's something I've always wanted to see
implemented, but never
On 1/18/07, Richard Kenner [EMAIL PROTECTED] wrote:
I'm not immediately aware of too many cases where lowering the IL is
going to expose new opportunities to track and optimize nonzero/zero
bits stuff.
Bitfield are the big one. If you have both bitfield and logical operations,
you can often
On 1/18/07, Jeffrey Law [EMAIL PROTECTED] wrote:
On Thu, 2007-01-18 at 12:44 +0530, pranav bhandarkar wrote:
On 1/17/07, Mircea Namolaru [EMAIL PROTECTED] wrote:
Thanks. Another question I have is that, in this case, will the
following
http://gcc.gnu.org/wiki/Sign_Extension_Removal
Thanks. Another question I have is that, in this case, will the
following
http://gcc.gnu.org/wiki/Sign_Extension_Removal
help in removal of the sign / zero extension ?
First, it seems to me that in your case:
(1) a = a | 1 /* a |= 1 */
(2) a = a | 1 /* a |= 1 */
the expressions a | 1 in
Thanks. Another question I have is that, in this case, will the
following
http://gcc.gnu.org/wiki/Sign_Extension_Removal
help in removal of the sign / zero extension ?
First, it seems to me that in your case:
(1) a = a | 1 /* a |= 1 */
(2) a = a | 1 /* a |= 1 */
the expressions a | 1 in
First, it seems to me that in your case:
(1) a = a | 1 /* a |= 1 */
(2) a = a | 1 /* a |= 1 */
the expressions a | 1 in (1) and (2) are different as the a
is not the same. So there is nothing to do for CSE.
It's not a CSE issue, but after (1), you know that the low-order bit of
a is a
[EMAIL PROTECTED] (Richard Kenner) wrote on 17/01/2007 18:04:20:
First, it seems to me that in your case:
(1) a = a | 1 /* a |= 1 */
(2) a = a | 1 /* a |= 1 */
the expressions a | 1 in (1) and (2) are different as the a
is not the same. So there is nothing to do for CSE.
It's
On 1/17/07, Mircea Namolaru [EMAIL PROTECTED] wrote:
[EMAIL PROTECTED] (Richard Kenner) wrote on 17/01/2007 18:04:20:
First, it seems to me that in your case:
(1) a = a | 1 /* a |= 1 */
(2) a = a | 1 /* a |= 1 */
the expressions a | 1 in (1) and (2) are different as the a
is not
Also this is removed for the case of integers by the CSE pass
IIRC . The problem arises only for the type being a char or a short.
Yes, That is true. With gcc 4.1 one of the 'or's gets eliminated for
'int'. I am putting below two sets of logs. The first just before
cse_main and the second just
On 1/17/07, Mircea Namolaru [EMAIL PROTECTED] wrote:
Thanks. Another question I have is that, in this case, will the
following
http://gcc.gnu.org/wiki/Sign_Extension_Removal
help in removal of the sign / zero extension ?
First, it seems to me that in your case:
(1) a = a | 1 /* a |= 1 */
Hello Everyone,
I have the following source code
static int i;
static char a;
char foo_gen(int);
void foo_assert(char);
void foo ()
{
int *x = i;
a = foo_gen(0);
a |= 1; /* 1-*/
if (*x) goto end:
a | =1; /* -2--*/
foo_assert(a);
end:
return;
}
Now I expect
On 1/15/07, pranav bhandarkar [EMAIL PROTECTED] wrote:
Hello Everyone,
I have the following source code
static int i;
static char a;
char foo_gen(int);
void foo_assert(char);
void foo ()
{
int *x = i;
a = foo_gen(0);
a |= 1; /* 1-*/
if (*x) goto end:
a | =1; /*
On 1/15/07, Richard Guenther [EMAIL PROTECTED] wrote:
On 1/15/07, pranav bhandarkar [EMAIL PROTECTED] wrote:
Hello Everyone,
I have the following source code
static int i;
static char a;
char foo_gen(int);
void foo_assert(char);
void foo ()
{
int *x = i;
a = foo_gen(0);
a
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