re PR tree-optimization/92691 (ICE in strlen_dom_walker::before_dom_children at…

re PR tree-optimization/92691 (ICE in strlen_dom_walker::before_dom_children at gcc/tree-ssa-strlen.c:5177 since r274933)

	PR tree-optimization/92691
	* tree-ssa-strlen.c (handle_store): Clarify return value meaning
	in function comment.
	(strlen_check_and_optimize_call): Likewise.  For handle_printf_call
	calls, return !handle_printf_call rather than always returning true.
	(check_and_optimize_stmt): Describe return value meaning in function
	comment.  Formatting fix.

	* gcc.dg/tree-ssa/builtin-snprintf-10.c: New test.

From-SVN: r278803

gcc/ChangeLog

+2019-11-28  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/92691
+	* tree-ssa-strlen.c (handle_store): Clarify return value meaning
+	in function comment.
+	(strlen_check_and_optimize_call): Likewise.  For handle_printf_call
+	calls, return !handle_printf_call rather than always returning true.
+	(check_and_optimize_stmt): Describe return value meaning in function
+	comment.  Formatting fix.
+
 2019-11-28  Jan Hubicka  <hubicka@ucw.cz>
 
 	* profile-count.c (profile_count::to_sreal_scale): Handle correctly

gcc/testsuite/ChangeLog

 2019-11-28  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/92691
+	* gcc.dg/tree-ssa/builtin-snprintf-10.c: New test.
+
 	PR c++/92695
 	* g++.dg/warn/inline3.C: New test.
 

gcc/testsuite/gcc.dg/tree-ssa/builtin-snprintf-10.c

+/* PR tree-optimization/92691 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void
+foo (int x, char *y)
+{
+  if (x != 0)
+    __builtin_snprintf (y, 0, "foo");
+}

gcc/tree-ssa-strlen.c

@@ -4300,7 +4300,8 @@ count_nonzero_bytes (tree exp, unsigned lenrange[3], bool *nulterm,
 /* Handle a single or multibyte store other than by a built-in function,
    either via a single character assignment or by multi-byte assignment
    either via MEM_REF or via a type other than char (such as in
-   '*(int*)a = 12345').  Return true when handled.  */
+   '*(int*)a = 12345').  Return true to let the caller advance *GSI to
+   the next statement in the basic block and false otherwise.  */
 
 static bool
 handle_store (gimple_stmt_iterator *gsi, bool *zero_write, const vr_values *rvals)
@@ -4728,8 +4729,8 @@ is_char_type (tree type)
 }
 
 /* Check the built-in call at GSI for validity and optimize it.
-   Return true to let the caller advance *GSI to the statement
-   in the CFG and false otherwise.  */
+   Return true to let the caller advance *GSI to the next statement
+   in the basic block and false otherwise.  */
 
 static bool
 strlen_check_and_optimize_call (gimple_stmt_iterator *gsi,
@@ -4738,16 +4739,13 @@ strlen_check_and_optimize_call (gimple_stmt_iterator *gsi,
 {
   gimple *stmt = gsi_stmt (*gsi);
 
+  /* When not optimizing we must be checking printf calls which
+     we do even for user-defined functions when they are declared
+     with attribute format.  */
   if (!flag_optimize_strlen
       || !strlen_optimize
       || !valid_builtin_call (stmt))
-    {
-      /* When not optimizing we must be checking printf calls which
-	 we do even for user-defined functions when they are declared
-	 with attribute format.  */
-      handle_printf_call (gsi, rvals);
-      return true;
-    }
+    return !handle_printf_call (gsi, rvals);
 
   tree callee = gimple_call_fndecl (stmt);
   switch (DECL_FUNCTION_CODE (callee))
@@ -4806,7 +4804,8 @@ strlen_check_and_optimize_call (gimple_stmt_iterator *gsi,
 	return false;
       break;
     default:
-      handle_printf_call (gsi, rvals);
+      if (handle_printf_call (gsi, rvals))
+	return false;
       break;
     }
 
@@ -4932,7 +4931,8 @@ handle_integral_assign (gimple_stmt_iterator *gsi, bool *cleanup_eh)
 /* Attempt to check for validity of the performed access a single statement
    at *GSI using string length knowledge, and to optimize it.
    If the given basic block needs clean-up of EH, CLEANUP_EH is set to
-   true.  */
+   true.  Return true to let the caller advance *GSI to the next statement
+   in the basic block and false otherwise.  */
 
 static bool
 check_and_optimize_stmt (gimple_stmt_iterator *gsi, bool *cleanup_eh,
@@ -4973,32 +4973,32 @@ check_and_optimize_stmt (gimple_stmt_iterator *gsi, bool *cleanup_eh,
 	/* Handle assignment to a character.  */
 	handle_integral_assign (gsi, cleanup_eh);
       else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs))
-      {
-	tree type = TREE_TYPE (lhs);
-	if (TREE_CODE (type) == ARRAY_TYPE)
-	  type = TREE_TYPE (type);
+	{
+	  tree type = TREE_TYPE (lhs);
+	  if (TREE_CODE (type) == ARRAY_TYPE)
+	    type = TREE_TYPE (type);
 
-	bool is_char_store = is_char_type (type);
-	if (!is_char_store && TREE_CODE (lhs) == MEM_REF)
-	  {
-	    /* To consider stores into char objects via integer types
-	       other than char but not those to non-character objects,
-	       determine the type of the destination rather than just
-	       the type of the access.  */
-	    tree ref = TREE_OPERAND (lhs, 0);
-	    type = TREE_TYPE (ref);
-	    if (TREE_CODE (type) == POINTER_TYPE)
-	      type = TREE_TYPE (type);
-	    if (TREE_CODE (type) == ARRAY_TYPE)
-	      type = TREE_TYPE (type);
-	    if (is_char_type (type))
-	      is_char_store = true;
-	  }
+	  bool is_char_store = is_char_type (type);
+	  if (!is_char_store && TREE_CODE (lhs) == MEM_REF)
+	    {
+	      /* To consider stores into char objects via integer types
+		 other than char but not those to non-character objects,
+		 determine the type of the destination rather than just
+		 the type of the access.  */
+	      tree ref = TREE_OPERAND (lhs, 0);
+	      type = TREE_TYPE (ref);
+	      if (TREE_CODE (type) == POINTER_TYPE)
+		type = TREE_TYPE (type);
+	      if (TREE_CODE (type) == ARRAY_TYPE)
+		type = TREE_TYPE (type);
+	      if (is_char_type (type))
+		is_char_store = true;
+	    }
 
-	/* Handle a single or multibyte assignment.  */
-	if (is_char_store && !handle_store (gsi, &zero_write, rvals))
-	  return false;
-      }
+	  /* Handle a single or multibyte assignment.  */
+	  if (is_char_store && !handle_store (gsi, &zero_write, rvals))
+	    return false;
+	}
     }
   else if (gcond *cond = dyn_cast<gcond *> (stmt))
     {