builtins.c (fold_builtin_floor): Fold floor (x) where x is nonnegative to trunc (x).

2006-10-24  Richard Guenther  <rguenther@suse.de>

	* builtins.c (fold_builtin_floor): Fold floor (x) where
	x is nonnegative to trunc (x).
	(fold_builtin_int_roundingfn): Fold lfloor (x) where x is
	nonnegative to FIX_TRUNC_EXPR.

	* gcc.dg/builtins-57.c: New testcase.

From-SVN: r117998

gcc/ChangeLog

 2006-10-24  Richard Guenther  <rguenther@suse.de>
 
+	* builtins.c (fold_builtin_floor): Fold floor (x) where
+	x is nonnegative to trunc (x).
+	(fold_builtin_int_roundingfn): Fold lfloor (x) where x is
+	nonnegative to FIX_TRUNC_EXPR.
+
+2006-10-24  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/29567
 	* tree-vrp.c (register_edge_assert_for_1): Fix wrong logic
 	for TRUTH_NOT_EXPR.  Clarify comments.

gcc/builtins.c

@@ -7355,6 +7355,12 @@ fold_builtin_floor (tree fndecl, tree arglist)
 	}
     }
 
+  /* Fold floor (x) where x is nonnegative to trunc (x).  */
+  if (tree_expr_nonnegative_p (arg))
+    return build_function_call_expr (mathfn_built_in (TREE_TYPE (arg),
+						      BUILT_IN_TRUNC),
+				     arglist);
+
   return fold_trunc_transparent_mathfn (fndecl, arglist);
 }
 
@@ -7473,6 +7479,18 @@ fold_builtin_int_roundingfn (tree fndecl, tree arglist)
 	}
     }
 
+  switch (DECL_FUNCTION_CODE (fndecl))
+    {
+    CASE_FLT_FN (BUILT_IN_LFLOOR):
+    CASE_FLT_FN (BUILT_IN_LLFLOOR):
+      /* Fold lfloor (x) where x is nonnegative to FIX_TRUNC (x).  */
+      if (tree_expr_nonnegative_p (arg))
+	return fold_build1 (FIX_TRUNC_EXPR, TREE_TYPE (TREE_TYPE (fndecl)),
+			    arg);
+      break;
+    default:;
+    }
+
   return fold_fixed_mathfn (fndecl, arglist);
 }
 

gcc/testsuite/ChangeLog

 2006-10-24  Richard Guenther  <rguenther@suse.de>
 
+	* gcc.dg/builtins-57.c: New testcase.
+
+2006-10-24  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/29567
 	* gfortran.fortran-torture/compile/vrp_1.f90: New testcase.
 

gcc/testsuite/gcc.dg/builtins-57.c

+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-gimple" } */
+
+double foo (double x)
+{
+  return __builtin_floor (__builtin_fabs (x));
+}
+
+long bar (double x)
+{
+  return __builtin_lfloor (__builtin_fabs (x));
+}
+
+/* { dg-final { scan-tree-dump-not "lfloor" "gimple" } } */
+/* { dg-final { scan-tree-dump "trunc" "gimple" } } */
+/* { dg-final { cleanup-tree-dump "gimple" } } */