Re: [PATCH] Factor out division by squares and remove division around comparisons (2/2)

2017-11-19 Thread Jeff Law 
On 09/06/2017 03:55 AM, Jackson Woodruff wrote:
> Hi all,
> 
> A minor improvement came to mind while updating other parts of this patch.
> 
> I've updated a testcase to make it more clear and a condition now uses a
> call to is_division_by rather than manually checking those conditions.
> 
> Jackson
> 
> On 08/30/2017 05:32 PM, Jackson Woodruff wrote:
>> Hi all,
>>
>> I've attached a new version of the patch in response to a few of
>> Wilco's comments in person.
>>
>> The end product of the pass is still the same, but I have fixed
>> several bugs.
>>
>> Now tested independently of the other patches.
>>
>> On 08/15/2017 03:07 PM, Richard Biener wrote:
>>> On Thu, Aug 10, 2017 at 4:10 PM, Jackson Woodruff
>>>  wrote:
 Hi all,

 The patch implements the some of the division optimizations discussed in

 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71026 .

 We now reassociate (as discussed in the bug report):

  x / (y * y) -> x  * (1 / y) * (1 / y)

 If it is reasonable to do so. This is done with
 -funsafe-math-optimizations.

 Bootstrapped and regtested with part (1/2). OK for trunk?
>>>
>>> I believe your enhancement shows the inherent weakness of
>>> CSE of reciprocals in that it works from the defs.  It will
>>> handle x / (y * y) but not x / (y * y * y).
>>>
>>> I think a rewrite of this mini-pass is warranted.
>>
>> I suspect that there might be more to gain by of handling the case of
>> x / (y * z) rather than the case of x / (y**n), but I agree that this
>> pass could do more.
>>
>>>
>>> Richard.
>>>
 Jackson

 gcc/

 2017-08-03  Jackson Woodruff  

  PR 71026/tree-optimization
  * tree-ssa-math-opts (is_division_by_square,
  is_square_of, insert_sqaure_reciprocals): New.
  (insert_reciprocals): Change to insert reciprocals
  before a division by a square.
  (execute_cse_reciprocals_1): Change to consider
  division by a square.


 gcc/testsuite

 2017-08-03  Jackson Woodruff  

  PR 71026/tree-optimization
  * gcc.dg/associate_division_1.c: New.

>>
>> Thanks,
>>
>> Jackson.
>>
>> Updated ChangeLog:
>>
>> gcc/
>>
>> 2017-08-30  Jackson Woodruff  
>>
>>  PR 71026/tree-optimization
>>  * tree-ssa-math-opts (is_division_by_square, is_square_of): New.
>>  (insert_reciprocals): Change to insert reciprocals
>>  before a division by a square and to insert the square
>>  of a reciprocal.
>>  (execute_cse_reciprocals_1): Change to consider
>>  division by a square.
>>  (register_division_in): Add importance parameter.
>>
>> gcc/testsuite
>>
>> 2017-08-30  Jackson Woodruff  
>>
>>  PR 71026/tree-optimization
>>  * gcc.dg/extract_recip_3.c: New.
>>  * gcc.dg/extract_recip_4.c: New.
>>  * gfortran.dg/extract_recip_1.f: New.
OK for the trunk.   Sorry for the delays.

Do you have commit privileges in GCC?

Jeff

Re: [PATCH] Factor out division by squares and remove division around comparisons (2/2)

2017-11-16 Thread Wilco Dijkstra 

ping


From: Jackson Woodruff <jackson.woodr...@foss.arm.com>
Sent: 06 September 2017 10:55
To: Richard Biener
Cc: Wilco Dijkstra; kyrylo.tkac...@foss.arm.com; Joseph S. Myers; GCC Patches
Subject: Re: [PATCH] Factor out division by squares and remove division around 
comparisons (2/2)
  

Hi all,

A minor improvement came to mind while updating other parts of this patch.

I've updated a testcase to make it more clear and a condition now uses a 
call to is_division_by rather than manually checking those conditions.

Jackson

On 08/30/2017 05:32 PM, Jackson Woodruff wrote:
> Hi all,
> 
> I've attached a new version of the patch in response to a few of Wilco's 
> comments in person.
> 
> The end product of the pass is still the same, but I have fixed several 
> bugs.
> 
> Now tested independently of the other patches.
> 
> On 08/15/2017 03:07 PM, Richard Biener wrote:
>> On Thu, Aug 10, 2017 at 4:10 PM, Jackson Woodruff
>> <jackson.woodr...@foss.arm.com> wrote:
>>> Hi all,
>>>
>>> The patch implements the some of the division optimizations discussed in
>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71026 .
>>>
>>> We now reassociate (as discussed in the bug report):
>>>
>>>  x / (y * y) -> x  * (1 / y) * (1 / y)
>>>
>>> If it is reasonable to do so. This is done with
>>> -funsafe-math-optimizations.
>>>
>>> Bootstrapped and regtested with part (1/2). OK for trunk?
>>
>> I believe your enhancement shows the inherent weakness of
>> CSE of reciprocals in that it works from the defs.  It will
>> handle x / (y * y) but not x / (y * y * y).
>>
>> I think a rewrite of this mini-pass is warranted.
> 
> I suspect that there might be more to gain by of handling the case of
> x / (y * z) rather than the case of x / (y**n), but I agree that this 
> pass could do more.
> 
>>
>> Richard.
>>
>>> Jackson
>>>
>>> gcc/
>>>
>>> 2017-08-03  Jackson Woodruff  <jackson.woodr...@arm.com>
>>>
>>>  PR 71026/tree-optimization
>>>  * tree-ssa-math-opts (is_division_by_square,
>>>  is_square_of, insert_sqaure_reciprocals): New.
>>>  (insert_reciprocals): Change to insert reciprocals
>>>  before a division by a square.
>>>  (execute_cse_reciprocals_1): Change to consider
>>>  division by a square.
>>>
>>>
>>> gcc/testsuite
>>>
>>> 2017-08-03  Jackson Woodruff  <jackson.woodr...@arm.com>
>>>
>>>  PR 71026/tree-optimization
>>>  * gcc.dg/associate_division_1.c: New.
>>>
> 
> Thanks,
> 
> Jackson.
> 
> Updated ChangeLog:
> 
> gcc/
> 
> 2017-08-30  Jackson Woodruff  <jackson.woodr...@arm.com>
> 
>  PR 71026/tree-optimization
>  * tree-ssa-math-opts (is_division_by_square, is_square_of): New.
>  (insert_reciprocals): Change to insert reciprocals
>  before a division by a square and to insert the square
>  of a reciprocal.
>  (execute_cse_reciprocals_1): Change to consider
>  division by a square.
>  (register_division_in): Add importance parameter.
> 
> gcc/testsuite
> 
> 2017-08-30  Jackson Woodruff  <jackson.woodr...@arm.com>
> 
>  PR 71026/tree-optimization
>  * gcc.dg/extract_recip_3.c: New.
>  * gcc.dg/extract_recip_4.c: New.
>  * gfortran.dg/extract_recip_1.f: New.
diff --git a/gcc/testsuite/gcc.dg/extract_recip_3.c 
b/gcc/testsuite/gcc.dg/extract_recip_3.c
new file mode 100644
index 
..ad9f2dc36f1e695ceca1f50bc78f4ac4fbb2e787
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/extract_recip_3.c
@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -fdump-tree-optimized" } */
+
+float
+extract_square (float *a, float *b, float x, float y)
+{
+  *a = 3 / (y * y);
+  *b = 5 / (y * y);
+
+  return x / (y * y);
+}
+
+/* Don't expect the 'powmult' (calculation of y * y)
+   to be deleted until a later pass, so look for one
+   more multiplication than strictly necessary.  */
+float
+extract_recip (float *a, float *b, float x, float y, float z)
+{
+  *a = 7 / y;
+  *b = x / (y * y);
+
+  return z / y;
+}
+
+/* 4 For the pointers to a, b, 4 multiplications in 'extract_square',
+   4 multiplications in 'extract_recip' expected.  */
+/* { dg-final { scan-tree-dump-times " \\* " 12 "optimized" } } */
+
+/* 1 division in 'extract_square', 1 division in 'extract_recip'. */
+/* { dg-final { scan-tree-dump-times " / " 2 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/extract_recip

Re: [PATCH] Factor out division by squares and remove division around comparisons (2/2)

2017-09-06 Thread Jackson Woodruff 

Hi all,

A minor improvement came to mind while updating other parts of this patch.

I've updated a testcase to make it more clear and a condition now uses a 
call to is_division_by rather than manually checking those conditions.


Jackson

On 08/30/2017 05:32 PM, Jackson Woodruff wrote:

Hi all,

I've attached a new version of the patch in response to a few of Wilco's 
comments in person.


The end product of the pass is still the same, but I have fixed several 
bugs.


Now tested independently of the other patches.

On 08/15/2017 03:07 PM, Richard Biener wrote:

On Thu, Aug 10, 2017 at 4:10 PM, Jackson Woodruff
 wrote:

Hi all,

The patch implements the some of the division optimizations discussed in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71026 .

We now reassociate (as discussed in the bug report):

 x / (y * y) -> x  * (1 / y) * (1 / y)

If it is reasonable to do so. This is done with
-funsafe-math-optimizations.

Bootstrapped and regtested with part (1/2). OK for trunk?


I believe your enhancement shows the inherent weakness of
CSE of reciprocals in that it works from the defs.  It will
handle x / (y * y) but not x / (y * y * y).

I think a rewrite of this mini-pass is warranted.


I suspect that there might be more to gain by of handling the case of
x / (y * z) rather than the case of x / (y**n), but I agree that this 
pass could do more.




Richard.


Jackson

gcc/

2017-08-03  Jackson Woodruff  

 PR 71026/tree-optimization
 * tree-ssa-math-opts (is_division_by_square,
 is_square_of, insert_sqaure_reciprocals): New.
 (insert_reciprocals): Change to insert reciprocals
 before a division by a square.
 (execute_cse_reciprocals_1): Change to consider
 division by a square.


gcc/testsuite

2017-08-03  Jackson Woodruff  

 PR 71026/tree-optimization
 * gcc.dg/associate_division_1.c: New.



Thanks,

Jackson.

Updated ChangeLog:

gcc/

2017-08-30  Jackson Woodruff  

 PR 71026/tree-optimization
 * tree-ssa-math-opts (is_division_by_square, is_square_of): New.
 (insert_reciprocals): Change to insert reciprocals
 before a division by a square and to insert the square
 of a reciprocal.
 (execute_cse_reciprocals_1): Change to consider
 division by a square.
 (register_division_in): Add importance parameter.

gcc/testsuite

2017-08-30  Jackson Woodruff  

 PR 71026/tree-optimization
 * gcc.dg/extract_recip_3.c: New.
 * gcc.dg/extract_recip_4.c: New.
 * gfortran.dg/extract_recip_1.f: New.
diff --git a/gcc/testsuite/gcc.dg/extract_recip_3.c 
b/gcc/testsuite/gcc.dg/extract_recip_3.c
new file mode 100644
index 
..ad9f2dc36f1e695ceca1f50bc78f4ac4fbb2e787
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/extract_recip_3.c
@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -fdump-tree-optimized" } */
+
+float
+extract_square (float *a, float *b, float x, float y)
+{
+  *a = 3 / (y * y);
+  *b = 5 / (y * y);
+
+  return x / (y * y);
+}
+
+/* Don't expect the 'powmult' (calculation of y * y)
+   to be deleted until a later pass, so look for one
+   more multiplication than strictly necessary.  */
+float
+extract_recip (float *a, float *b, float x, float y, float z)
+{
+  *a = 7 / y;
+  *b = x / (y * y);
+
+  return z / y;
+}
+
+/* 4 For the pointers to a, b, 4 multiplications in 'extract_square',
+   4 multiplications in 'extract_recip' expected.  */
+/* { dg-final { scan-tree-dump-times " \\* " 12 "optimized" } } */
+
+/* 1 division in 'extract_square', 1 division in 'extract_recip'. */
+/* { dg-final { scan-tree-dump-times " / " 2 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/extract_recip_4.c 
b/gcc/testsuite/gcc.dg/extract_recip_4.c
new file mode 100644
index 
..83105c60ced5c2671f3793d76482c35502712a2c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/extract_recip_4.c
@@ -0,0 +1,35 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -fdump-tree-optimized" } */
+
+/* Don't expect any of these divisions to be extracted.  */
+double f (double x, int p)
+{
+  if (p > 0)
+{
+  return 1.0/(x * x);
+}
+
+  if (p > -1)
+{
+  return x * x * x;
+}
+  return  1.0 /(x);
+}
+
+/* Expect a reciprocal to be extracted here.  */
+double g (double *a, double x, double y)
+{
+  *a = 3 / y;
+  double k = x / (y * y);
+
+  if (y * y == 2.0)
+return k + 1 / y;
+  else
+return k - 1 / y;
+}
+
+/* Expect 2 divisions in 'f' and 1 in 'g'.  */
+/* { dg-final { scan-tree-dump-times " / " 3 "optimized" } } */
+/* Expect 3 multiplications in 'f' and 4 in 'g'.  Also
+   expect one for the point to a.  */
+/* { dg-final { scan-tree-dump-times " \\* " 8 "optimized" } } */
diff --git a/gcc/testsuite/gfortran.dg/extract_recip_1.f

Re: [PATCH] Factor out division by squares and remove division around comparisons (2/2)

2017-08-30 Thread Jackson Woodruff 

Hi all,

I've attached a new version of the patch in response to a few of Wilco's 
comments in person.


The end product of the pass is still the same, but I have fixed several 
bugs.


Now tested independently of the other patches.

On 08/15/2017 03:07 PM, Richard Biener wrote:

On Thu, Aug 10, 2017 at 4:10 PM, Jackson Woodruff
 wrote:

Hi all,

The patch implements the some of the division optimizations discussed in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71026 .

We now reassociate (as discussed in the bug report):

 x / (y * y) -> x  * (1 / y) * (1 / y)

If it is reasonable to do so. This is done with
-funsafe-math-optimizations.

Bootstrapped and regtested with part (1/2). OK for trunk?


I believe your enhancement shows the inherent weakness of
CSE of reciprocals in that it works from the defs.  It will
handle x / (y * y) but not x / (y * y * y).

I think a rewrite of this mini-pass is warranted.


I suspect that there might be more to gain by of handling the case of
x / (y * z) rather than the case of x / (y**n), but I agree that this 
pass could do more.




Richard.


Jackson

gcc/

2017-08-03  Jackson Woodruff  

 PR 71026/tree-optimization
 * tree-ssa-math-opts (is_division_by_square,
 is_square_of, insert_sqaure_reciprocals): New.
 (insert_reciprocals): Change to insert reciprocals
 before a division by a square.
 (execute_cse_reciprocals_1): Change to consider
 division by a square.


gcc/testsuite

2017-08-03  Jackson Woodruff  

 PR 71026/tree-optimization
 * gcc.dg/associate_division_1.c: New.



Thanks,

Jackson.

Updated ChangeLog:

gcc/

2017-08-30  Jackson Woodruff  

PR 71026/tree-optimization
* tree-ssa-math-opts (is_division_by_square, is_square_of): New.
(insert_reciprocals): Change to insert reciprocals
before a division by a square and to insert the square
of a reciprocal.
(execute_cse_reciprocals_1): Change to consider
division by a square.
(register_division_in): Add importance parameter.

gcc/testsuite

2017-08-30  Jackson Woodruff  

PR 71026/tree-optimization
* gcc.dg/extract_recip_3.c: New.
* gcc.dg/extract_recip_4.c: New.
* gfortran.dg/extract_recip_1.f: New.
diff --git a/gcc/testsuite/gcc.dg/extract_recip_3.c 
b/gcc/testsuite/gcc.dg/extract_recip_3.c
new file mode 100644
index 
..0ea3fdf5cca06a0806a55185ef8b0a4b0507
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/extract_recip_3.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -fdump-tree-optimized" } */
+
+float
+extract_square (float x, float y, float *a, float *b)
+{
+  *a = 3 / (y * y);
+  *b = 5 / (y * y);
+
+  return x / (y * y);
+}
+
+/* Don't expect the 'powmult' (calculation of y * y)
+   to be deleted until a later pass, so look for one
+   more multiplication than strictly necessary.  */
+float
+extract_recip (float *w, float x, float y, float z)
+{
+  *w = 7 / y;
+
+  return x / (y * y) + z / y;
+}
+
+/* 3 For the pointers to a, b and w, 4 multiplications in 'extract_square',
+   5 multiplications in 'extract_recip' expected.  */
+/* { dg-final { scan-tree-dump-times " \\* " 12 "optimized" } } */
+
+/* 1 division in 'extract_square', 1 division in 'extract_recip'. */
+/* { dg-final { scan-tree-dump-times " / " 2 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/extract_recip_4.c 
b/gcc/testsuite/gcc.dg/extract_recip_4.c
new file mode 100644
index 
..5a31d40ed910cdd1914cc1e82358493be428946a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/extract_recip_4.c
@@ -0,0 +1,33 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -fdump-tree-optimized" } */
+
+/* Don't expect any of these divisions to be extracted.  */
+double f (double x, int p)
+{
+  if (p > 0)
+{
+  return 1.0/(x * x);
+}
+
+  if (p > -1)
+{
+  return x * x * x;
+}
+  return  1.0 /(x);
+}
+
+/* Expect a reciprocal to be extracted here.  */
+double g (double x, double y)
+{
+  double k = x / (y * y);
+
+  if (y * y == 2.0)
+return k + 1 / y;
+  else
+return k - 1 / y;
+}
+
+/* Expect 2 divisions in 'f' and 1 in 'g'.  */
+/* { dg-final { scan-tree-dump-times " / " 3 "optimized" } } */
+/* Expect 3 multiplications in 'f' and 3 in 'g'.  */
+/* { dg-final { scan-tree-dump-times " \\* " 6 "optimized" } } */
diff --git a/gcc/testsuite/gfortran.dg/extract_recip_1.f 
b/gcc/testsuite/gfortran.dg/extract_recip_1.f
new file mode 100644
index 
..ecf05189773b6c2f46222857fd88fd010bfdf348
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/extract_recip_1.f
@@ -0,0 +1,19 @@
+! { dg-do compile }
+! { dg-options "-Ofast -fdump-tree-optimized" }
+
+  SUBROUTINE F(N,X,Y,Z,A,B)
+  DIMENSION

Re: [PATCH] Factor out division by squares and remove division around comparisons (2/2)

2017-08-15 Thread Richard Biener 
On Thu, Aug 10, 2017 at 4:10 PM, Jackson Woodruff
 wrote:
> Hi all,
>
> The patch implements the some of the division optimizations discussed in
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71026 .
>
> We now reassociate (as discussed in the bug report):
>
> x / (y * y) -> x  * (1 / y) * (1 / y)
>
> If it is reasonable to do so. This is done with
> -funsafe-math-optimizations.
>
> Bootstrapped and regtested with part (1/2). OK for trunk?

I believe your enhancement shows the inherent weakness of
CSE of reciprocals in that it works from the defs.  It will
handle x / (y * y) but not x / (y * y * y).

I think a rewrite of this mini-pass is warranted.

Richard.

> Jackson
>
> gcc/
>
> 2017-08-03  Jackson Woodruff  
>
> PR 71026/tree-optimization
> * tree-ssa-math-opts (is_division_by_square,
> is_square_of, insert_sqaure_reciprocals): New.
> (insert_reciprocals): Change to insert reciprocals
> before a division by a square.
> (execute_cse_reciprocals_1): Change to consider
> division by a square.
>
>
> gcc/testsuite
>
> 2017-08-03  Jackson Woodruff  
>
> PR 71026/tree-optimization
> * gcc.dg/associate_division_1.c: New.
>