The following fixes PR80974 by not being too clever when preserving
SSA info during VN. I didn't want to invent a way to unwind changes
done in this hack.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2017-06-06 Richard Biener <rguent...@suse.de>
PR tree-optimization/80974
* tree-ssa-sccvn.c (set_ssa_val_to): Do not change but only
keep or clear leaders SSA info.
* gcc.dg/torture/pr80974.c: New testcase.
Index: gcc/tree-ssa-sccvn.c
===================================================================
--- gcc/tree-ssa-sccvn.c (revision 248913)
+++ gcc/tree-ssa-sccvn.c (working copy)
@@ -3328,6 +3328,9 @@ set_ssa_val_to (tree from, tree to)
== get_addr_base_and_unit_offset (TREE_OPERAND (to, 0), &toff))
&& coff == toff))
{
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, " (changed)\n");
+
/* If we equate two SSA names we have to make the side-band info
of the leader conservative (and remember whatever original value
was present). */
@@ -3342,22 +3345,6 @@ set_ssa_val_to (tree from, tree to)
gimple_bb (SSA_NAME_DEF_STMT (to))))
/* Keep the info from the dominator. */
;
- else if (SSA_NAME_IS_DEFAULT_DEF (from)
- || dominated_by_p_w_unex
- (gimple_bb (SSA_NAME_DEF_STMT (to)),
- gimple_bb (SSA_NAME_DEF_STMT (from))))
- {
- /* Save old info. */
- if (! VN_INFO (to)->info.range_info)
- {
- VN_INFO (to)->info.range_info = SSA_NAME_RANGE_INFO (to);
- VN_INFO (to)->range_info_anti_range_p
- = SSA_NAME_ANTI_RANGE_P (to);
- }
- /* Use that from the dominator. */
- SSA_NAME_RANGE_INFO (to) = SSA_NAME_RANGE_INFO (from);
- SSA_NAME_ANTI_RANGE_P (to) = SSA_NAME_ANTI_RANGE_P (from);
- }
else
{
/* Save old info. */
@@ -3369,6 +3356,12 @@ set_ssa_val_to (tree from, tree to)
}
/* Rather than allocating memory and unioning the info
just clear it. */
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "clearing range info of ");
+ print_generic_expr (dump_file, to);
+ fprintf (dump_file, "\n");
+ }
SSA_NAME_RANGE_INFO (to) = NULL;
}
}
@@ -3381,17 +3374,6 @@ set_ssa_val_to (tree from, tree to)
gimple_bb (SSA_NAME_DEF_STMT (to))))
/* Keep the info from the dominator. */
;
- else if (SSA_NAME_IS_DEFAULT_DEF (from)
- || dominated_by_p_w_unex
- (gimple_bb (SSA_NAME_DEF_STMT (to)),
- gimple_bb (SSA_NAME_DEF_STMT (from))))
- {
- /* Save old info. */
- if (! VN_INFO (to)->info.ptr_info)
- VN_INFO (to)->info.ptr_info = SSA_NAME_PTR_INFO (to);
- /* Use that from the dominator. */
- SSA_NAME_PTR_INFO (to) = SSA_NAME_PTR_INFO (from);
- }
else if (! SSA_NAME_PTR_INFO (from)
/* Handle the case of trivially equivalent info. */
|| memcmp (SSA_NAME_PTR_INFO (to),
@@ -3403,14 +3385,18 @@ set_ssa_val_to (tree from, tree to)
VN_INFO (to)->info.ptr_info = SSA_NAME_PTR_INFO (to);
/* Rather than allocating memory and unioning the info
just clear it. */
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "clearing points-to info of ");
+ print_generic_expr (dump_file, to);
+ fprintf (dump_file, "\n");
+ }
SSA_NAME_PTR_INFO (to) = NULL;
}
}
}
VN_INFO (from)->valnum = to;
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " (changed)\n");
return true;
}
if (dump_file && (dump_flags & TDF_DETAILS))
Index: gcc/testsuite/gcc.dg/torture/pr80974.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr80974.c (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr80974.c (working copy)
@@ -0,0 +1,39 @@
+/* { dg-do run } */
+
+int a, b, c, d, e, f, g[4];
+
+static int fn1 ()
+{
+ int h, i;
+ if (b)
+ goto L1;
+L2:;
+ int m = a;
+ while (1)
+ {
+ int n = 2;
+ e = !f && (n = 5);
+ if (e)
+ for (h = 0; h < 9; h++)
+ for (i = 0; i < 6; i++)
+ if (a)
+ g[h] = 4;
+ if (d)
+ goto L2;
+ a & n || b;
+L1:
+ if (a)
+ L3:
+ c = m;
+ if (a)
+ goto L3;
+ if (b < 5)
+ return 0;
+ }
+}
+
+int main ()
+{
+ fn1 ();
+ return 0;
+}
