re PR tree-optimization/14819 ([tree-ssa] strchr is not folded at tree-level)

	PR tree-optimization/14819
	* builtins.c (fold_builtin_strchr): New.
	(fold_builtin_1): Handle BUILT_IN_STRCHR and BUILT_IN_STRRCHR
	with fold_builtin_strchr().

From-SVN: r82464

2 files changed, 54 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 98cd593..6fd198e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2004-05-30  Steven Bosscher  <stevenb@suse.de>
+
+	PR tree-optimization/14819
+	* builtins.c (fold_builtin_strchr): New.
+	(fold_builtin_1): Handle BUILT_IN_STRCHR and BUILT_IN_STRRCHR
+	with fold_builtin_strchr().
+
 2004-05-30  Kazu Hirata  <kazu@cs.umass.edu>
 
 	* bb-reorder.c, builtins.c, c-common.c, c-gimplify.c,
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 28eb129..4bac999 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -7085,6 +7085,47 @@ fold_builtin_strncpy (tree exp)
   return 0;
 }
 
+/* Fold function call to builtin strchr and strrchr.
+   Return NULL_TREE if no simplification can be made.  */
+
+static tree
+fold_builtin_strchr (tree exp, bool actually_strrchr)
+{
+  tree arglist = TREE_OPERAND (exp, 1);
+  if (!validate_arglist (arglist, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
+    return 0;
+  else
+    {
+      tree s1 = TREE_VALUE (arglist), s2 = TREE_VALUE (TREE_CHAIN (arglist));
+      const char *p1;
+
+      if (TREE_CODE (s2) != INTEGER_CST)
+	return 0;
+
+      p1 = c_getstr (s1);
+      if (p1 != NULL)
+	{
+	  char c;
+	  const char *r;
+
+	  if (target_char_cast (s2, &c))
+	    return 0;
+
+	  r = actually_strrchr ? strrchr (p1, c) : strchr (p1, c);
+
+	  if (r == NULL)
+	    return fold_convert (TREE_TYPE (s1), integer_zero_node);
+
+	  /* Return an offset into the constant string argument.  */
+	  return fold (build2 (PLUS_EXPR, TREE_TYPE (s1),
+			       s1, fold_convert (TREE_TYPE (s1),
+						 ssize_int (r - p1))));
+	}
+
+      return 0;
+    }
+}
+
 /* Fold function call to builtin memcmp.  Return
    NULL_TREE if no simplification can be made.  */
 
@@ -7796,6 +7837,12 @@ fold_builtin_1 (tree exp)
     case BUILT_IN_STRNCPY:
       return fold_builtin_strncpy (exp);
 
+    case BUILT_IN_STRCHR:
+      return fold_builtin_strchr (exp, false);
+
+    case BUILT_IN_STRRCHR:
+      return fold_builtin_strchr (exp, true);
+
     case BUILT_IN_MEMCMP:
       return fold_builtin_memcmp (exp);