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re PR tree-optimization/89789 (Compile time hog during RPO VN)

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2019-03-25  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/89789
	* tree-ssa-sccvn.c (set_ssa_val_to): Do not allow lattice
	changes from non-undefined back to undefined.

	* gcc.dg/torture/pr89789.c: New testcase.

From-SVN: r269917
This commit is contained in:
Richard Biener 2019-03-25 13:53:50 +00:00 • committed by Richard Biener
parent be5ce04a61
commit 8d6419db2c
4 changed files with 59 additions and 4 deletions
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6
gcc/ChangeLog
View file

@ -1,3 +1,9 @@
2019-03-25 Richard Biener <rguenther@suse.de>
PR tree-optimization/89789
* tree-ssa-sccvn.c (set_ssa_val_to): Do not allow lattice
changes from non-undefined back to undefined.
2019-03-25 Thomas Otto <thomas.otto@pdv-fs.de>
* dwarf2out.c (comp_dir_string): cached_wd could be set to both a

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2019-03-25 Richard Biener <rguenther@suse.de>
PR tree-optimization/89789
* gcc.dg/torture/pr89789.c: New testcase.
2019-03-25 Nathan Sidwell <nathan@acm.org>
* g++.dg/abi/lambda-static-1.C: New.

23
gcc/testsuite/gcc.dg/torture/pr89789.c Normal file
View file

@ -0,0 +1,23 @@
/* { dg-do compile } */
int x2;
void
m2 (void)
{
goto gg;
int fz, vh = 0;
for (fz = 0; fz < 1; ++fz)
{
vh ^= x2;
if (0)
{
gg:
x2 %= 1;
x2 += vh;
}
}
}

29
gcc/tree-ssa-sccvn.c
View file

@ -3746,10 +3746,13 @@ set_ssa_val_to (tree from, tree to)
}
return false;
}
else if (currval != VN_TOP
&& ! is_gimple_min_invariant (currval)
&& ! ssa_undefined_value_p (currval, false)
&& is_gimple_min_invariant (to))
bool curr_invariant = is_gimple_min_invariant (currval);
bool curr_undefined = (TREE_CODE (currval) == SSA_NAME
&& ssa_undefined_value_p (currval, false));
if (currval != VN_TOP
&& !curr_invariant
&& !curr_undefined
&& is_gimple_min_invariant (to))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
@ -3764,6 +3767,24 @@ set_ssa_val_to (tree from, tree to)
}
to = from;
}
else if (currval != VN_TOP
&& !curr_undefined
&& TREE_CODE (to) == SSA_NAME
&& ssa_undefined_value_p (to, false))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Forcing VARYING instead of changing "
"value number of ");
print_generic_expr (dump_file, from);
fprintf (dump_file, " from ");
print_generic_expr (dump_file, currval);
fprintf (dump_file, " (non-undefined) to ");
print_generic_expr (dump_file, to);
fprintf (dump_file, " (undefined)\n");
}
to = from;
}
else if (TREE_CODE (to) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (to))
to = from;