Hi,
this patch fixes PR70700, an ICE in
tree-ssa-structalias.c:dump_pred_graph for the test-case contained in
the patch.
In the constraint graph, a node representing a variable varinfo_t var is
represented as the corresponding var->id, ranging from 1 to
FIRST_REF_NODE - 1.
A node representing a DEREF of a varinfo_t var is represented as the
corresponding var->id + FIRST_REF_NODE, ranging from FIRST_REF_NODE + 1
to LAST_REF_NODE.
So, for a DEREF node, we need to substract FIRST_REF_NODE to find the
corresponding variable. This logic is missing in a print statement in
dump_pred_graph (which is triggered with TDF_GRAPH), which causes the ICE.
This patch fixes the ICE by substracting FIRST_REF_NODE from the node
number of a DEREF node to find the varinfo, and prints it as a DEREF
node (by adding an '*' prefix).
Bootstrapped and reg-tested on x86_64. Extracted graphs from ealias dump
and verified that valid pdfs were produced.
OK for trunk?
Thanks,
- Tom
Fix ICE in dump_pred_graph
2016-05-02 Marek Polacek <pola...@redhat.com>
Tom de Vries <t...@codesourcery.com>
PR tree-optimization/70700
* tree-ssa-structalias.c (dump_pred_graph): Fix getting varinfo for ids
bigger than FIRST_REF_NODE.
* gcc.dg/pr70700.c: New test.
---
gcc/testsuite/gcc.dg/pr70700.c | 15 +++++++++++++++
gcc/tree-ssa-structalias.c | 6 +++++-
2 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/gcc/testsuite/gcc.dg/pr70700.c b/gcc/testsuite/gcc.dg/pr70700.c
new file mode 100644
index 0000000..613cd29
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr70700.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fdump-tree-ealias-graph" } */
+
+struct S
+{
+ long m;
+};
+
+struct S
+fn1 (struct S *a)
+{
+ if (a->m)
+ a->m |= 2;
+ return *a;
+}
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 0a41494..d66bdfa 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -2241,7 +2241,11 @@ dump_pred_graph (struct scc_info *si, FILE *file)
if (graph->points_to[i]
&& !bitmap_empty_p (graph->points_to[i]))
{
- fprintf (file, "[label=\"%s = {", get_varinfo (i)->name);
+ if (i < FIRST_REF_NODE)
+ fprintf (file, "[label=\"%s = {", get_varinfo (i)->name);
+ else
+ fprintf (file, "[label=\"*%s = {",
+ get_varinfo (i - FIRST_REF_NODE)->name);
unsigned j;
bitmap_iterator bi;
EXECUTE_IF_SET_IN_BITMAP (graph->points_to[i], 0, j, bi)
