[Bug tree-optimization/81403] [8 Regression] wrong code at -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81403 --- Comment #9 from Richard Biener --- Author: rguenth Date: Thu Nov 23 08:30:41 2017 New Revision: 255092 URL: https://gcc.gnu.org/viewcvs?rev=255092&root=gcc&view=rev Log: 2017-11-23 Richard Biener PR tree-optimization/81403 * tree-ssa-pre.c (get_representative_for): Add parameter specifying a block we need a leader relative to. (phi_translate_1): For nary processing require a leader from get_representative_for given we run expression simplification using match-and-simplify. Remove previous fix. Modified: trunk/gcc/ChangeLog trunk/gcc/tree-ssa-pre.c
[Bug tree-optimization/81403] [8 Regression] wrong code at -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81403 Richard Biener changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution|--- |FIXED --- Comment #8 from Richard Biener --- Fixed.
[Bug tree-optimization/81403] [8 Regression] wrong code at -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81403 --- Comment #7 from Richard Biener --- Author: rguenth Date: Tue Jul 18 07:35:40 2017 New Revision: 250297 URL: https://gcc.gnu.org/viewcvs?rev=250297&root=gcc&view=rev Log: 2017-07-18 Richard Biener PR tree-optimization/80620 PR tree-optimization/81403 * tree-ssa-pre.c (phi_translate_1): Clear range and points-to info when re-using a VN table entry. * gcc.dg/torture/pr80620.c: New testcase. * gcc.dg/torture/pr81403.c: Likewise. Added: trunk/gcc/testsuite/gcc.dg/torture/pr80620.c trunk/gcc/testsuite/gcc.dg/torture/pr81403.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/tree-ssa-pre.c
[Bug tree-optimization/81403] [8 Regression] wrong code at -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81403 --- Comment #6 from Richard Biener --- Kind-of a duplicate of PR80620 as well. Testing a patch.
[Bug tree-optimization/81403] [8 Regression] wrong code at -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81403
--- Comment #5 from Richard Biener ---
So this is during partial-PRE insertion where after PRE insertion of
Found partial redundancy for expression {bit_not_expr,_13} (0020)
Inserted _33 = ~_3;
in predecessor 5 (0014)
Created phi prephitmp_34 = PHI <_33(5), _8(6)>
in block 7 (0020)
we value-replace 0020 by prephitmp_34 and thus during partial-PRE
phi-translation
find, when translating _14 & 10393, _8 for _14 (0020) to be translated across
the edge exposing the range.
On the other edge we get from translating _14 & 10393 all the way to
translating
var_9.5_12 = var_9 as operand which leads us to var_9.1_2 = var_9 and
ultimatively
to _8 via "simplification" of ~_3 which has a leader of _33 (fine IMHO), but
unfortunately _33 has a value number of _8.
So PRE doing any insertion of a lexically equivalent expression will
necessarily
end up with a SCCVN value-number that might have range info that is not valid
there. Thus:
tree result = vn_nary_op_lookup_pieces (newnary->length,
newnary->opcode,
newnary->type,
&newnary->op[0],
&nary);
if (result && is_gimple_min_invariant (result))
return get_or_alloc_expr_for_constant (result);
expr = pre_expr_pool.allocate ();
expr->kind = NARY;
expr->id = 0;
if (nary)
{
PRE_EXPR_NARY (expr) = nary;
new_val_id = nary->value_id;
get_or_alloc_expression_id (expr);
}
needs adjustment to push away range-info.
[Bug tree-optimization/81403] [8 Regression] wrong code at -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81403 Richard Biener changed: What|Removed |Added Priority|P3 |P1 Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org Target Milestone|--- |8.0 --- Comment #4 from Richard Biener --- Mine :/
[Bug tree-optimization/81403] [8 Regression] wrong code at -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81403 --- Comment #3 from Marc Glisse --- /* x & C -> x if we know that x & ~C == 0. */ Not clear where it is getting the bogus range/nonzero information from, I thought we had fixed all the places reusing SSA_NAMEs with stale information.
[Bug tree-optimization/81403] [8 Regression] wrong code at -O3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81403 Martin Liška changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2017-07-12 CC||marxin at gcc dot gnu.org, ||rguenth at gcc dot gnu.org Summary|wrong code at -O3 |[8 Regression] wrong code ||at -O3 Ever confirmed|0 |1 --- Comment #2 from Martin Liška --- Confirmed, started with r247596.
