* Handle CONSTRUCTOR in operand_equal_p
@ 2015-10-14 16:27 Jan Hubicka
2015-10-14 17:26 ` Jeff Law
2015-10-14 18:42 ` Richard Biener
0 siblings, 2 replies; 9+ messages in thread
From: Jan Hubicka @ 2015-10-14 16:27 UTC (permalink / raw)
To: gcc-patches, rguenther
Hi,
this patch adds the CONSTRUCTOR case discussed while back. Only empty
constructors are matched, as those are only appearing in gimple operand.
I tested that during bootstrap about 7500 matches are for empty ctors.
There are couple hundred for non-empty probably used on generic.
Bootstrapped/regtested x86_64-linux, OK?
Honza
* fold-const.c (operand_equal_p): Match empty constructors.
Index: fold-const.c
===================================================================
--- fold-const.c (revision 228735)
+++ fold-const.c (working copy)
@@ -2890,6 +2891,11 @@ operand_equal_p (const_tree arg0, const_
return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
flags | OEP_ADDRESS_OF
| OEP_CONSTANT_ADDRESS_OF);
+ case CONSTRUCTOR:
+ /* In GIMPLE empty constructors are allowed in initializers of
+ vector types. */
+ return (!vec_safe_length (CONSTRUCTOR_ELTS (arg0))
+ && !vec_safe_length (CONSTRUCTOR_ELTS (arg1)));
default:
break;
}
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Handle CONSTRUCTOR in operand_equal_p
2015-10-14 16:27 Handle CONSTRUCTOR in operand_equal_p Jan Hubicka
@ 2015-10-14 17:26 ` Jeff Law
2015-10-14 17:35 ` Jan Hubicka
2015-10-14 18:42 ` Richard Biener
1 sibling, 1 reply; 9+ messages in thread
From: Jeff Law @ 2015-10-14 17:26 UTC (permalink / raw)
To: Jan Hubicka, gcc-patches, rguenther
On 10/14/2015 10:27 AM, Jan Hubicka wrote:
> Hi,
> this patch adds the CONSTRUCTOR case discussed while back. Only empty
> constructors are matched, as those are only appearing in gimple operand.
> I tested that during bootstrap about 7500 matches are for empty ctors.
> There are couple hundred for non-empty probably used on generic.
>
> Bootstrapped/regtested x86_64-linux, OK?
>
> Honza
>
> * fold-const.c (operand_equal_p): Match empty constructors.
OK. It'd be useful to have a test which shows that matching these
results in some kind of difference we can see in the dump files.
jeff
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Handle CONSTRUCTOR in operand_equal_p
2015-10-14 17:26 ` Jeff Law
@ 2015-10-14 17:35 ` Jan Hubicka
0 siblings, 0 replies; 9+ messages in thread
From: Jan Hubicka @ 2015-10-14 17:35 UTC (permalink / raw)
To: Jeff Law; +Cc: Jan Hubicka, gcc-patches, rguenther
> On 10/14/2015 10:27 AM, Jan Hubicka wrote:
> >Hi,
> >this patch adds the CONSTRUCTOR case discussed while back. Only empty
> >constructors are matched, as those are only appearing in gimple operand.
> >I tested that during bootstrap about 7500 matches are for empty ctors.
> >There are couple hundred for non-empty probably used on generic.
> >
> >Bootstrapped/regtested x86_64-linux, OK?
> >
> >Honza
> >
> > * fold-const.c (operand_equal_p): Match empty constructors.
> OK. It'd be useful to have a test which shows that matching these
> results in some kind of difference we can see in the dump files.
I will try to think of something. My main motivation is to get ipa-icf-gimple
and operand_equal_p into sync and hopefully comonize the logic. Having testcase
then will be a lot easier (any function with empty constructor will do)
Honza
>
> jeff
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Handle CONSTRUCTOR in operand_equal_p
2015-10-14 16:27 Handle CONSTRUCTOR in operand_equal_p Jan Hubicka
2015-10-14 17:26 ` Jeff Law
@ 2015-10-14 18:42 ` Richard Biener
2015-10-14 23:55 ` Jan Hubicka
1 sibling, 1 reply; 9+ messages in thread
From: Richard Biener @ 2015-10-14 18:42 UTC (permalink / raw)
To: Jan Hubicka, gcc-patches
On October 14, 2015 6:27:02 PM GMT+02:00, Jan Hubicka <hubicka@ucw.cz> wrote:
>Hi,
>this patch adds the CONSTRUCTOR case discussed while back. Only empty
>constructors are matched, as those are only appearing in gimple
>operand.
>I tested that during bootstrap about 7500 matches are for empty ctors.
>There are couple hundred for non-empty probably used on generic.
>
>Bootstrapped/regtested x86_64-linux, OK?
>
>Honza
>
> * fold-const.c (operand_equal_p): Match empty constructors.
>Index: fold-const.c
>===================================================================
>--- fold-const.c (revision 228735)
>+++ fold-const.c (working copy)
>@@ -2890,6 +2891,11 @@ operand_equal_p (const_tree arg0, const_
> return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,
>0),
> flags | OEP_ADDRESS_OF
> | OEP_CONSTANT_ADDRESS_OF);
>+ case CONSTRUCTOR:
>+ /* In GIMPLE empty constructors are allowed in initializers of
>+ vector types. */
The comment is wrong (or at least odd),
On gimple an empty vector constructor should be folded to a VECTOR_CST.
>+ return (!vec_safe_length (CONSTRUCTOR_ELTS (arg0))
>+ && !vec_safe_length (CONSTRUCTOR_ELTS (arg1)));
> default:
> break;
> }
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Handle CONSTRUCTOR in operand_equal_p
2015-10-14 18:42 ` Richard Biener
@ 2015-10-14 23:55 ` Jan Hubicka
2015-10-15 6:57 ` Richard Biener
0 siblings, 1 reply; 9+ messages in thread
From: Jan Hubicka @ 2015-10-14 23:55 UTC (permalink / raw)
To: Richard Biener; +Cc: Jan Hubicka, gcc-patches
> On October 14, 2015 6:27:02 PM GMT+02:00, Jan Hubicka <hubicka@ucw.cz> wrote:
> >Hi,
> >this patch adds the CONSTRUCTOR case discussed while back. Only empty
> >constructors are matched, as those are only appearing in gimple
> >operand.
> >I tested that during bootstrap about 7500 matches are for empty ctors.
> >There are couple hundred for non-empty probably used on generic.
> >
> >Bootstrapped/regtested x86_64-linux, OK?
> >
> >Honza
> >
> > * fold-const.c (operand_equal_p): Match empty constructors.
> >Index: fold-const.c
> >===================================================================
> >--- fold-const.c (revision 228735)
> >+++ fold-const.c (working copy)
> >@@ -2890,6 +2891,11 @@ operand_equal_p (const_tree arg0, const_
> > return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,
> >0),
> > flags | OEP_ADDRESS_OF
> > | OEP_CONSTANT_ADDRESS_OF);
> >+ case CONSTRUCTOR:
> >+ /* In GIMPLE empty constructors are allowed in initializers of
> >+ vector types. */
>
> The comment is wrong (or at least odd),
> On gimple an empty vector constructor should be folded to a VECTOR_CST.
Hmm, I tought we have a={} i.e. for clearing whole structure.
If we never have constructors appearing as gimple operands, I guess we don't
really need the code at gimple level (because at least so far ipa-icf has
separate path to compare constructors).
Honza
>
> >+ return (!vec_safe_length (CONSTRUCTOR_ELTS (arg0))
> >+ && !vec_safe_length (CONSTRUCTOR_ELTS (arg1)));
> > default:
> > break;
> > }
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Handle CONSTRUCTOR in operand_equal_p
2015-10-14 23:55 ` Jan Hubicka
@ 2015-10-15 6:57 ` Richard Biener
2015-10-21 19:10 ` Jan Hubicka
0 siblings, 1 reply; 9+ messages in thread
From: Richard Biener @ 2015-10-15 6:57 UTC (permalink / raw)
To: Jan Hubicka; +Cc: gcc-patches
On October 15, 2015 1:55:09 AM GMT+02:00, Jan Hubicka <hubicka@ucw.cz> wrote:
>> On October 14, 2015 6:27:02 PM GMT+02:00, Jan Hubicka
><hubicka@ucw.cz> wrote:
>> >Hi,
>> >this patch adds the CONSTRUCTOR case discussed while back. Only
>empty
>> >constructors are matched, as those are only appearing in gimple
>> >operand.
>> >I tested that during bootstrap about 7500 matches are for empty
>ctors.
>> >There are couple hundred for non-empty probably used on generic.
>> >
>> >Bootstrapped/regtested x86_64-linux, OK?
>> >
>> >Honza
>> >
>> > * fold-const.c (operand_equal_p): Match empty constructors.
>> >Index: fold-const.c
>> >===================================================================
>> >--- fold-const.c (revision 228735)
>> >+++ fold-const.c (working copy)
>> >@@ -2890,6 +2891,11 @@ operand_equal_p (const_tree arg0, const_
>> > return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,
>> >0),
>> > flags | OEP_ADDRESS_OF
>> > | OEP_CONSTANT_ADDRESS_OF);
>> >+ case CONSTRUCTOR:
>> >+ /* In GIMPLE empty constructors are allowed in initializers of
>> >+ vector types. */
>>
>> The comment is wrong (or at least odd),
>> On gimple an empty vector constructor should be folded to a
>VECTOR_CST.
>
>Hmm, I tought we have a={} i.e. for clearing whole structure.
Yes we do, but then the comment should refer to aggregate types.
>If we never have constructors appearing as gimple operands, I guess we
>don't
>really need the code at gimple level (because at least so far ipa-icf
>has
>separate path to compare constructors).
>
>Honza
>>
>> >+ return (!vec_safe_length (CONSTRUCTOR_ELTS (arg0))
>> >+ && !vec_safe_length (CONSTRUCTOR_ELTS (arg1)));
>> > default:
>> > break;
>> > }
>>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Handle CONSTRUCTOR in operand_equal_p
2015-10-15 6:57 ` Richard Biener
@ 2015-10-21 19:10 ` Jan Hubicka
2015-10-22 7:39 ` Richard Biener
0 siblings, 1 reply; 9+ messages in thread
From: Jan Hubicka @ 2015-10-21 19:10 UTC (permalink / raw)
To: Richard Biener; +Cc: Jan Hubicka, gcc-patches
Hi,
this is updated patch I am going to commit. As discussed, we also need to match
non-empty CONSTRUCTOR of vectors, but those should never be having CONSTANT flags
set, so they need care in the other path trhough operand_equal_p, so I will post
separate patch for that.
I updated the comment per Richard's comment and added a testcase. Vuriously
enoug we fold "val? (struct a){} : (struct a){}" only in PRE (tailmerging).
W/o the patch even .optimized dump has the test and we fold it away only after
lowering to RTL:
ret (int val)
{
struct a D.1764;
<bb 2>:
if (val_2(D) != 0)
goto <bb 3>;
else
goto <bb 4>;
<bb 3>:
D.1764 = {};
goto <bb 5>;
<bb 4>:
D.1764 = {};
<bb 5>:
return D.1764;
}
ret:
.LFB0:
.cfi_startproc
xorl %eax, %eax
ret
.cfi_endproc
With the patch we get:
ret (int val)
{
struct a D.1764;
<bb 2>:
D.1764 = {};
return D.1764;
}
Honza
* fold-const.c (operand_equal_p): Add code matching empty
constructors.
* gcc.dg/tree-ssa/operand-equal-1.c: Verify that empty constructors
are matched.
Index: fold-const.c
===================================================================
--- fold-const.c (revision 229133)
+++ fold-const.c (working copy)
@@ -2892,6 +2892,11 @@ operand_equal_p (const_tree arg0, const_
return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
flags | OEP_ADDRESS_OF
| OEP_CONSTANT_ADDRESS_OF);
+ case CONSTRUCTOR:
+ /* In GIMPLE empty constructors are allowed in initializers of
+ aggregates. */
+ return (!vec_safe_length (CONSTRUCTOR_ELTS (arg0))
+ && !vec_safe_length (CONSTRUCTOR_ELTS (arg1)));
default:
break;
}
Index: testsuite/gcc.dg/tree-ssa/operand-equal-1.c
===================================================================
--- testsuite/gcc.dg/tree-ssa/operand-equal-1.c (revision 0)
+++ testsuite/gcc.dg/tree-ssa/operand-equal-1.c (revision 0)
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-pre" } */
+struct a {int a,b;};
+struct a ret(int val)
+{
+ return val? (struct a){} : (struct a){};
+}
+/* { dg-final { scan-tree-dump-not "if " "pre"} } */
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Handle CONSTRUCTOR in operand_equal_p
2015-10-21 19:10 ` Jan Hubicka
@ 2015-10-22 7:39 ` Richard Biener
2015-10-23 5:43 ` Jan Hubicka
0 siblings, 1 reply; 9+ messages in thread
From: Richard Biener @ 2015-10-22 7:39 UTC (permalink / raw)
To: Jan Hubicka; +Cc: gcc-patches
On Wed, 21 Oct 2015, Jan Hubicka wrote:
> Hi,
> this is updated patch I am going to commit. As discussed, we also need to match
> non-empty CONSTRUCTOR of vectors, but those should never be having CONSTANT flags
> set, so they need care in the other path trhough operand_equal_p, so I will post
> separate patch for that.
>
> I updated the comment per Richard's comment and added a testcase. Vuriously
> enoug we fold "val? (struct a){} : (struct a){}" only in PRE (tailmerging).
> W/o the patch even .optimized dump has the test and we fold it away only after
> lowering to RTL:
> ret (int val)
> {
> struct a D.1764;
>
> <bb 2>:
> if (val_2(D) != 0)
> goto <bb 3>;
> else
> goto <bb 4>;
>
> <bb 3>:
> D.1764 = {};
> goto <bb 5>;
>
> <bb 4>:
> D.1764 = {};
>
> <bb 5>:
> return D.1764;
>
> }
>
> ret:
> .LFB0:
> .cfi_startproc
> xorl %eax, %eax
> ret
> .cfi_endproc
>
> With the patch we get:
>
> ret (int val)
> {
> struct a D.1764;
>
> <bb 2>:
> D.1764 = {};
> return D.1764;
>
> }
But only via GENERIC folding I suppose. Yes, we don't value-number
aggregates and generally PRE (and DOM via excessive jump-threading)
is the only pass that remotely handles this kind of situation.
code hoisting/sinking would maybe catch this but as this involves
memory I'm not sure the implementation ontop of PRE that is stuck
in some PR would catch it.
Richard.
> Honza
>
> * fold-const.c (operand_equal_p): Add code matching empty
> constructors.
> * gcc.dg/tree-ssa/operand-equal-1.c: Verify that empty constructors
> are matched.
>
> Index: fold-const.c
> ===================================================================
> --- fold-const.c (revision 229133)
> +++ fold-const.c (working copy)
> @@ -2892,6 +2892,11 @@ operand_equal_p (const_tree arg0, const_
> return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
> flags | OEP_ADDRESS_OF
> | OEP_CONSTANT_ADDRESS_OF);
> + case CONSTRUCTOR:
> + /* In GIMPLE empty constructors are allowed in initializers of
> + aggregates. */
> + return (!vec_safe_length (CONSTRUCTOR_ELTS (arg0))
> + && !vec_safe_length (CONSTRUCTOR_ELTS (arg1)));
> default:
> break;
> }
> Index: testsuite/gcc.dg/tree-ssa/operand-equal-1.c
> ===================================================================
> --- testsuite/gcc.dg/tree-ssa/operand-equal-1.c (revision 0)
> +++ testsuite/gcc.dg/tree-ssa/operand-equal-1.c (revision 0)
> @@ -0,0 +1,8 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-pre" } */
> +struct a {int a,b;};
> +struct a ret(int val)
> +{
> + return val? (struct a){} : (struct a){};
> +}
> +/* { dg-final { scan-tree-dump-not "if " "pre"} } */
>
>
--
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: Handle CONSTRUCTOR in operand_equal_p
2015-10-22 7:39 ` Richard Biener
@ 2015-10-23 5:43 ` Jan Hubicka
0 siblings, 0 replies; 9+ messages in thread
From: Jan Hubicka @ 2015-10-23 5:43 UTC (permalink / raw)
To: Richard Biener; +Cc: Jan Hubicka, gcc-patches
>
> But only via GENERIC folding I suppose. Yes, we don't value-number
> aggregates and generally PRE (and DOM via excessive jump-threading)
> is the only pass that remotely handles this kind of situation.
I actually think it is tail merging unifying the code, but I did not
really look too deep into it.
Honza
>
> code hoisting/sinking would maybe catch this but as this involves
> memory I'm not sure the implementation ontop of PRE that is stuck
> in some PR would catch it.
>
> Richard.
>
> > Honza
> >
> > * fold-const.c (operand_equal_p): Add code matching empty
> > constructors.
> > * gcc.dg/tree-ssa/operand-equal-1.c: Verify that empty constructors
> > are matched.
> >
> > Index: fold-const.c
> > ===================================================================
> > --- fold-const.c (revision 229133)
> > +++ fold-const.c (working copy)
> > @@ -2892,6 +2892,11 @@ operand_equal_p (const_tree arg0, const_
> > return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
> > flags | OEP_ADDRESS_OF
> > | OEP_CONSTANT_ADDRESS_OF);
> > + case CONSTRUCTOR:
> > + /* In GIMPLE empty constructors are allowed in initializers of
> > + aggregates. */
> > + return (!vec_safe_length (CONSTRUCTOR_ELTS (arg0))
> > + && !vec_safe_length (CONSTRUCTOR_ELTS (arg1)));
> > default:
> > break;
> > }
> > Index: testsuite/gcc.dg/tree-ssa/operand-equal-1.c
> > ===================================================================
> > --- testsuite/gcc.dg/tree-ssa/operand-equal-1.c (revision 0)
> > +++ testsuite/gcc.dg/tree-ssa/operand-equal-1.c (revision 0)
> > @@ -0,0 +1,8 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -fdump-tree-pre" } */
> > +struct a {int a,b;};
> > +struct a ret(int val)
> > +{
> > + return val? (struct a){} : (struct a){};
> > +}
> > +/* { dg-final { scan-tree-dump-not "if " "pre"} } */
> >
> >
>
> --
> Richard Biener <rguenther@suse.de>
> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2015-10-23 5:22 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-10-14 16:27 Handle CONSTRUCTOR in operand_equal_p Jan Hubicka
2015-10-14 17:26 ` Jeff Law
2015-10-14 17:35 ` Jan Hubicka
2015-10-14 18:42 ` Richard Biener
2015-10-14 23:55 ` Jan Hubicka
2015-10-15 6:57 ` Richard Biener
2015-10-21 19:10 ` Jan Hubicka
2015-10-22 7:39 ` Richard Biener
2015-10-23 5:43 ` Jan Hubicka
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