tree-optimization/121035 - handle stray VN values without expression

When VN iterates we can end up with unreachable inserted expressions
in the expression tables which in turn will not be added to their
value by PREs compute_avail.  This will later ICE when we pick
them up and want to generate them.  Deal with this by giving up.

	PR tree-optimization/121035
	* tree-ssa-pre.cc (find_or_generate_expression): Handle
	values without expression.

	* gcc.dg/pr121035.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/pr121035.c b/gcc/testsuite/gcc.dg/pr121035.c
new file mode 100644 (file)
index 0000000..fc0edce
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr121035.c
@@ -0,0 +1,94 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fgimple" } */
+
+int printf(const char *, ...);
+int a, b, d;
+unsigned c;
+int __GIMPLE (ssa,startwith("pre"))
+main ()
+{
+  unsigned int g;
+  int f;
+  unsigned int _1;
+  unsigned int _2;
+  int _3;
+  int _4;
+  int _5;
+  unsigned int _6;
+  unsigned int _7;
+  int _10;
+  unsigned int _11;
+  _Bool _19;
+  _Bool _20;
+  _Bool _22;
+  int _25;
+
+  __BB(2):
+  _25 = a;
+  if (_25 != 0)
+    goto __BB11;
+  else
+    goto __BB10;
+
+  __BB(11):
+  goto __BB3;
+
+  __BB(3):
+  f_26 = __PHI (__BB12: f_18, __BB11: 0);
+  g_15 = c;
+  if (f_26 != 0)
+    goto __BB4;
+  else
+    goto __BB5;
+
+  __BB(4):
+  __builtin_putchar (48);
+  goto __BB5;
+
+  __BB(5):
+  _1 = c;
+  _2 = _1 << 1;
+  _3 = a;
+  _4 = d;
+  _5 = _3 * _4;
+  if (_5 != 0)
+    goto __BB7;
+  else
+    goto __BB6;
+
+  __BB(6):
+  goto __BB7;
+
+  __BB(7):
+  _11 = __PHI (__BB5: 0u, __BB6: 4294967295u);
+  _6 = g_15 * 4294967294u;
+  _7 = _6 | _11;
+  _20 = _3 != 0;
+  _19 = _7 != 0u;
+  _22 = _19 & _20;
+  if (_22 != _Literal (_Bool) 0)
+    goto __BB9;
+  else
+    goto __BB8;
+
+  __BB(8):
+  goto __BB9;
+
+  __BB(9):
+  _10 = __PHI (__BB7: 1, __BB8: 0);
+  b = _10;
+  f_18 = (int) _1;
+  if (_3 != 0)
+    goto __BB12;
+  else
+    goto __BB10;
+
+  __BB(12):
+  goto __BB3;
+
+  __BB(10):
+  return 0;
+
+}
+
+

diff --git a/gcc/tree-ssa-pre.cc b/gcc/tree-ssa-pre.cc
index f6c531e4892d790da32965136226beadced3f8e6..99331730bc2ecf15c150ed150fab0437e6feb25c 100644 (file)
--- a/gcc/tree-ssa-pre.cc
+++ b/gcc/tree-ssa-pre.cc
@@ -2773,16 +2773,17 @@ find_or_generate_expression (basic_block block, tree op, gimple_seq *stmts)
   bitmap exprset = value_expressions[lookfor];
   bitmap_iterator bi;
   unsigned int i;
-  EXECUTE_IF_SET_IN_BITMAP (exprset, 0, i, bi)
-    {
-      pre_expr temp = expression_for_id (i);
-      /* We cannot insert random REFERENCE expressions at arbitrary
-        places.  We can insert NARYs which eventually re-materializes
-        its operand values.  */
-      if (temp->kind == NARY)
-       return create_expression_by_pieces (block, temp, stmts,
-                                           TREE_TYPE (op));
-    }
+  if (exprset)
+    EXECUTE_IF_SET_IN_BITMAP (exprset, 0, i, bi)
+      {
+       pre_expr temp = expression_for_id (i);
+       /* We cannot insert random REFERENCE expressions at arbitrary
+          places.  We can insert NARYs which eventually re-materializes
+          its operand values.  */
+       if (temp->kind == NARY)
+         return create_expression_by_pieces (block, temp, stmts,
+                                             TREE_TYPE (op));
+      }
 
   /* Defer.  */
   return NULL_TREE;