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[PATCH] Fix ccp (PR tree-optimization/56396)


Hi!

On the following patch gcc ICEs because malloc memory is corrupted.
The problem is that const_val array is allocated at the start of the pass,
but during the execution of ccp some new SSA_NAMEs are created
(update_call_from_tree if I remember well).

The following patch fixes that by making const_val a vector instead of
array, and growing it when needed.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2013-02-19  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/56396
	* tree-ssa-ccp.c (const_val): Change into vector.
	(get_value): Use !const_val.exists () instead of const_val == NULL,
	call safe_grow_cleared method if SSA_NAME_VERSION (var) is above
	last vector element.
	(set_value_varying): Call safe_grow_cleared method if
	SSA_NAME_VERSION (var) is above last vector element.
	(set_lattice_value): Likewise.
	(ccp_initialize): Call const_val.create (num_ssa_names) instead
	of XCNEWVEC.
	(do_dbg_cnt): Call safe_grow_cleared method if num_ssa_names
	is above vector length.
	(ccp_finalize): Call const_val.release ().

	* gcc.dg/pr56396.c: New test.

--- gcc/tree-ssa-ccp.c.jj	2013-01-11 09:02:48.000000000 +0100
+++ gcc/tree-ssa-ccp.c	2013-02-19 20:04:21.194681227 +0100
@@ -155,13 +155,13 @@ struct prop_value_d {
 
 typedef struct prop_value_d prop_value_t;
 
-/* Array of propagated constant values.  After propagation,
+/* Vector of propagated constant values.  After propagation,
    CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I).  If
    the constant is held in an SSA name representing a memory store
    (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual
    memory reference used to store (i.e., the LHS of the assignment
    doing the store).  */
-static prop_value_t *const_val;
+static vec<prop_value_t> const_val;
 
 static void canonicalize_float_value (prop_value_t *);
 static bool ccp_fold_stmt (gimple_stmt_iterator *);
@@ -295,9 +295,12 @@ get_value (tree var)
 {
   prop_value_t *val;
 
-  if (const_val == NULL)
+  if (!const_val.exists ())
     return NULL;
 
+  if (SSA_NAME_VERSION (var) >= const_val.length ())
+    const_val.safe_grow_cleared (SSA_NAME_VERSION (var) + 32);
+
   val = &const_val[SSA_NAME_VERSION (var)];
   if (val->lattice_val == UNINITIALIZED)
     *val = get_default_value (var);
@@ -333,8 +336,12 @@ get_constant_value (tree var)
 static inline void
 set_value_varying (tree var)
 {
-  prop_value_t *val = &const_val[SSA_NAME_VERSION (var)];
+  prop_value_t *val;
 
+  if (SSA_NAME_VERSION (var) >= const_val.length ())
+    const_val.safe_grow_cleared (SSA_NAME_VERSION (var) + 32);
+
+  val = &const_val[SSA_NAME_VERSION (var)];
   val->lattice_val = VARYING;
   val->value = NULL_TREE;
   val->mask = double_int_minus_one;
@@ -428,7 +435,12 @@ static bool
 set_lattice_value (tree var, prop_value_t new_val)
 {
   /* We can deal with old UNINITIALIZED values just fine here.  */
-  prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)];
+  prop_value_t *old_val;
+
+  if (SSA_NAME_VERSION (var) >= const_val.length ())
+    const_val.safe_grow_cleared (SSA_NAME_VERSION (var) + 32);
+
+  old_val = &const_val[SSA_NAME_VERSION (var)];
 
   canonicalize_float_value (&new_val);
 
@@ -713,7 +725,7 @@ ccp_initialize (void)
 {
   basic_block bb;
 
-  const_val = XCNEWVEC (prop_value_t, num_ssa_names);
+  const_val.create (num_ssa_names);
 
   /* Initialize simulation flags for PHI nodes and statements.  */
   FOR_EACH_BB (bb)
@@ -774,6 +786,9 @@ static void
 do_dbg_cnt (void)
 {
   unsigned i;
+
+  if (num_ssa_names >= const_val.length ())
+    const_val.safe_grow_cleared (num_ssa_names);
   for (i = 0; i < num_ssa_names; i++)
     {
       if (!dbg_cnt (ccp))
@@ -829,9 +844,8 @@ ccp_finalize (void)
   something_changed = substitute_and_fold (get_constant_value,
 					   ccp_fold_stmt, true);
 
-  free (const_val);
-  const_val = NULL;
-  return something_changed;;
+  const_val.release ();
+  return something_changed;
 }
 
 
--- gcc/testsuite/gcc.dg/pr56396.c.jj	2013-02-19 20:02:48.663057957 +0100
+++ gcc/testsuite/gcc.dg/pr56396.c	2013-02-19 19:59:00.000000000 +0100
@@ -0,0 +1,22 @@
+/* PR tree-optimization/56396 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fpic -g" } */
+
+struct S { char *s; int z; };
+struct T { int t; } *c, u;
+void bar (int, const char *);
+
+inline void *
+foo (void *x, char *y, int z)
+{
+  struct S s;
+  char b[256];
+  s.s = b;
+  s.z = __builtin___sprintf_chk (s.s, 1, __builtin_object_size (s.s, 2), "Require");
+  if (s.z < 0)
+    bar (u.t | c->t, "rls");
+  if (foo (x, s.s, s.z))
+    {
+    }
+  return (void *) 0;
+}

	Jakub


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