From c08b0d3f7b3539b26031de31d88dea6b94474577 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Mon, 27 May 2024 10:41:02 +0200
Subject: tree-optimization/115236 - more points-to *ANYTHING = x fixes

The stored-to ANYTHING handling has more holes, uncovered by treating
volatile accesses as ANYTHING.  We fail to properly build the
pred and succ graphs, in particular we may not elide direct nodes
from receiving from STOREDANYTHING.

	PR tree-optimization/115236
	* tree-ssa-structalias.cc (build_pred_graph): Properly
	handle *ANYTHING = X.
	(build_succ_graph): Likewise.  Do not elide direct nodes
	from receiving from STOREDANYTHING.

	* gcc.dg/pr115236.c: New testcase.
---
 gcc/testsuite/gcc.dg/pr115236.c | 12 ++++++++++++
 gcc/tree-ssa-structalias.cc     | 20 ++++++++++++++------
 2 files changed, 26 insertions(+), 6 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr115236.c

(limited to 'gcc')

diff --git a/gcc/testsuite/gcc.dg/pr115236.c b/gcc/testsuite/gcc.dg/pr115236.c
new file mode 100644
index 0000000..91edfab
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr115236.c
@@ -0,0 +1,12 @@
+/* { dg-do run } */
+/* { dg-options "-O -fno-tree-fre" } */
+
+int a, *b = &a;
+int main()
+{
+  int *c, *volatile *d = &c;
+  *d = b;
+  if (c != &a)
+    __builtin_abort();
+  return 0;
+}
diff --git a/gcc/tree-ssa-structalias.cc b/gcc/tree-ssa-structalias.cc
index 9cec2c6..330e64e 100644
--- a/gcc/tree-ssa-structalias.cc
+++ b/gcc/tree-ssa-structalias.cc
@@ -1312,7 +1312,12 @@ build_pred_graph (void)
 	{
 	  /* *x = y.  */
 	  if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
-	    add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
+	    {
+	      if (lhs.var == anything_id)
+		add_pred_graph_edge (graph, storedanything_id, rhsvar);
+	      else
+		add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
+	    }
 	}
       else if (rhs.type == DEREF)
 	{
@@ -1398,7 +1403,12 @@ build_succ_graph (void)
       if (lhs.type == DEREF)
 	{
 	  if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
-	    add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
+	    {
+	      if (lhs.var == anything_id)
+		add_graph_edge (graph, storedanything_id, rhsvar);
+	      else
+		add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
+	    }
 	}
       else if (rhs.type == DEREF)
 	{
@@ -1418,13 +1428,11 @@ build_succ_graph (void)
 	}
     }
 
-  /* Add edges from STOREDANYTHING to all non-direct nodes that can
-     receive pointers.  */
+  /* Add edges from STOREDANYTHING to all nodes that can receive pointers.  */
   t = find (storedanything_id);
   for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
     {
-      if (!bitmap_bit_p (graph->direct_nodes, i)
-	  && get_varinfo (i)->may_have_pointers)
+      if (get_varinfo (i)->may_have_pointers)
 	add_graph_edge (graph, find (i), t);
     }
 
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