[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 --- Comment #12 from Georg-Johann Lay gjl at gcc dot gnu.org 2013-03-04 11:12:42 UTC --- Author: gjl Date: Mon Mar 4 11:12:30 2013 New Revision: 196428 URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=196428 Log: PR testsuite/52641 PR tree-optimization/52631 * gcc.dg/tree-ssa/pr52631.c: Fix 16-bit int. Modified: trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gcc.dg/tree-ssa/pr52631.c
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 --- Comment #10 from Jeffrey A. Law law at gcc dot gnu.org 2013-01-20 05:01:04 UTC --- Author: law Date: Sun Jan 20 05:00:56 2013 New Revision: 195318 URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=195318 Log: PR tree-optimization/52631 * tree-ssa-sccvn (visit_use): Before looking up the original statement, try looking up the simplified expression. PR tree-optimization/52631 * tree-ssa/pr52631.c: New test. * tree-ssa/ssa-fre-9: Update expected output. Added: trunk/gcc/testsuite/gcc.dg/tree-ssa/pr52631.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-9.c trunk/gcc/tree-ssa-sccvn.c
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 Jeffrey A. Law law at redhat dot com changed: What|Removed |Added Status|ASSIGNED|RESOLVED CC||law at redhat dot com Resolution||FIXED Target Milestone|4.7.3 |4.8.0 --- Comment #11 from Jeffrey A. Law law at redhat dot com 2013-01-20 05:02:28 UTC --- Fixed on trunk.
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 Jakub Jelinek jakub at gcc dot gnu.org changed: What|Removed |Added Target Milestone|4.7.2 |4.7.3 --- Comment #9 from Jakub Jelinek jakub at gcc dot gnu.org 2012-09-20 10:16:19 UTC --- GCC 4.7.2 has been released.
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 Richard Guenther rguenth at gcc dot gnu.org changed: What|Removed |Added Target Milestone|4.7.1 |4.7.2 --- Comment #8 from Richard Guenther rguenth at gcc dot gnu.org 2012-06-14 08:21:25 UTC --- GCC 4.7.1 is being released, adjusting target milestone.
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 Richard Guenther rguenth at gcc dot gnu.org changed: What|Removed |Added Priority|P3 |P2 Known to work||4.3.6 --- Comment #7 from Richard Guenther rguenth at gcc dot gnu.org 2012-04-13 13:10:04 UTC --- That looks good apart from the use of valid_gimple_rhs_p which allows too much. I'd rather use get_gimple_rhs_class (TREE_CODE (simplified)) and allow GIMPLE_UNARY_RHS, GIMPLE_BINARY_RHS and GIMPLE_TERNARY_RHS here.
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 --- Comment #5 from Andrew Pinski pinskia at gcc dot gnu.org 2012-03-24 03:10:37 UTC --- Ok, I have a patch which only tries to looking up the simplified expression and then if we find it, use it, otherwise use the original expression. I now understand why this makes a difference (for FRE it does not though).
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631
--- Comment #6 from Andrew Pinski pinskia at gcc dot gnu.org 2012-03-24
03:21:29 UTC ---
Here is the simpler patch:
Index: tree-ssa-sccvn.c
===
--- tree-ssa-sccvn.c(revision 185559)
+++ tree-ssa-sccvn.c(working copy)
@@ -3295,6 +3295,17 @@ visit_use (tree use)
}
else
{
+ /* First try to lookup the simplified expression. */
+ if (simplified valid_gimple_rhs_p (simplified))
+ {
+ tree result = vn_nary_op_lookup (simplified, NULL);
+ if (result)
+ {
+ changed = set_ssa_val_to (lhs, result);
+ goto done;
+ }
+ }
+ /* Otherwise visit the original statement. */
switch (get_gimple_rhs_class (code))
{
case GIMPLE_UNARY_RHS:
CUT -
ChangeLog:
* tree-ssa-sccvn.c (visit_use): Before looking up the original statement, try
looking up the simplified expression.
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 Andrew Pinski pinskia at gcc dot gnu.org changed: What|Removed |Added Status|UNCONFIRMED |ASSIGNED Keywords||missed-optimization Last reconfirmed||2012-03-20 AssignedTo|unassigned at gcc dot |pinskia at gcc dot gnu.org |gnu.org | Ever Confirmed|0 |1 Summary|VN does not use simplified |[4.6/4.7/4.8 Regression] VN |expression for lookup |does not use simplified ||expression for lookup Target Milestone|--- |4.7.1 --- Comment #1 from Andrew Pinski pinskia at gcc dot gnu.org 2012-03-20 06:09:18 UTC --- I am working on a fix. Note I did not find this because a performance issue but rather I found this while working on my gimple SSA combiner/simplifer patches.
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 --- Comment #2 from Andrew Pinski pinskia at gcc dot gnu.org 2012-03-20 06:57:51 UTC --- Created attachment 26927 -- http://gcc.gnu.org/bugzilla/attachment.cgi?id=26927 Patch which fixes the problem
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631 --- Comment #3 from Richard Guenther rguenth at gcc dot gnu.org 2012-03-20 11:13:57 UTC --- Hmm, but then you'd pessimize the case where b_2 1 were available? Thus, don't you need to do the lookup with the original expression anyway if the lookup for the simplified expression fails? Oh, and doesn't the testcase show a missed canonicalization?
[Bug tree-optimization/52631] [4.6/4.7/4.8 Regression] VN does not use simplified expression for lookup
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52631
--- Comment #4 from Andrew Pinski pinskia at gcc dot gnu.org 2012-03-21
00:14:37 UTC ---
(In reply to comment #3)
Hmm, but then you'd pessimize the case where b_2 1 were available? Thus,
don't you need to do the lookup with the original expression anyway if the
lookup for the simplified expression fails? Oh, and doesn't the testcase
show a missed canonicalization?
My patch just gets us back to where we were before tuples.
Before tuples we would do:
else if (simplified)
{
if (TREE_CODE (lhs) == SSA_NAME)
{
VN_INFO (lhs)-has_constants = expr_has_constants (simplified);
/* We have to unshare the expression or else
valuizing may change the IL stream. */
VN_INFO (lhs)-expr = unshare_expr (simplified);
}
rhs = simplified;
}
And then use rhs in the switch statement for visit_unary_op/visit_binary_op .
I don't see a missed canonicalization anywhere as we are combing (a31)1 and
then calling fold on it and it returns a31 which is the correct thing to do.
The main issue is we never do a lookup on a31 after we do the simplification,
we only do it on the b1.
Let me see if I can understand the question about b1 being available, a
testcase would be something like:
unsigned f(unsigned a, unsigned b, unsigned c)
{
unsigned d = c1;
if(b)
c = a31;
return (c 1) + d;
}
--- CUT ---
PRE produces (with both the patch and before):
bb 2:
d_3 = c_2(D) 1;
if (b_4(D) != 0)
goto bb 3;
else
goto bb 5;
bb 5:
goto bb 4;
bb 3:
c_6 = a_5(D) 31;
pretmp.3_11 = c_6 1;
bb 4:
# c_1 = PHI c_2(D)(5), c_6(3)
# prephitmp.4_12 = PHI d_3(5), pretmp.3_11(3)
D.1713_7 = prephitmp.4_12;
D.1712_8 = D.1713_7 + d_3;
return D.1712_8;
Which means we don't even do the simplifications while doing a PRE anyways.
