diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c4aede67bcb..5a9e553c6c5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2007-01-19  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	PR middle-end/29335
+	* builtins.c (fold_builtin_1): Handle builtin fdim.
+
 2007-01-20  Jan Hubicka  <jh@suse.cz>
 
         * tree-ssa.c (init_tree_ssa): Do not call init_alias_heapvars.
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 82e5a1e7da2..bf57c7bf55e 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -9469,6 +9469,13 @@ fold_builtin_1 (tree fndecl, tree arglist, bool ignore)
 			     type, mpfr_atan2);
     break;
 
+    CASE_FLT_FN (BUILT_IN_FDIM):
+      if (validate_arglist (arglist, REAL_TYPE, REAL_TYPE, VOID_TYPE))
+	return do_mpfr_arg2 (TREE_VALUE (arglist),
+			     TREE_VALUE (TREE_CHAIN (arglist)),
+			     type, mpfr_dim);
+    break;
+
     CASE_FLT_FN (BUILT_IN_FMA):
       if (validate_arglist (arglist, REAL_TYPE, REAL_TYPE, REAL_TYPE, VOID_TYPE))
 	return do_mpfr_arg3 (TREE_VALUE (arglist),
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 640d3b789ee..e9f9c9f125a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2007-01-19  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* gcc.dg/torture/builtin-math-3.c: Test fdim.
+
 2007-01-19  Mike Stump  <mrs@apple.com>
 
 	* gcc.dg/darwin-ld-6.c: Remove, tests a linker flag that is going
diff --git a/gcc/testsuite/gcc.dg/torture/builtin-math-3.c b/gcc/testsuite/gcc.dg/torture/builtin-math-3.c
index 67304f8191e..b347dccbecc 100644
--- a/gcc/testsuite/gcc.dg/torture/builtin-math-3.c
+++ b/gcc/testsuite/gcc.dg/torture/builtin-math-3.c
@@ -294,6 +294,16 @@ int main (void)
   TESTIT2_R (atan2, -1.0, 0.0, -1.58, -1.57); /* atan2(-1,0) == -pi/2 */
   TESTIT2_R (atan2, 1.0, 0.0, 1.57, 1.58); /* atan2(1,0) == pi/2 */
 
+  TESTIT2 (fdim, 0.0, 0.0, 0.0); /* fdim(0,0) == 0 */
+  TESTIT2 (fdim, -0.0, 0.0, 0.0); /* fdim(-0,0) == 0 */
+  TESTIT2 (fdim, 0.0, -0.0, 0.0); /* fdim(0,-0) == 0 */
+  TESTIT2 (fdim, -0.0, -0.0, 0.0); /* fdim(-0,-0) == 0 */
+  TESTIT2 (fdim, 5.0, 5.0, 0.0); /* fdim(5,5) == 0 */
+  TESTIT2 (fdim, 5.0, 6.0, 0.0); /* fdim(5,6) == 0 */
+  TESTIT2 (fdim, 6.0, 5.0, 1.0); /* fdim(6,5) == 1 */
+  TESTIT2 (fdim, -5.0, -6.0, 1.0); /* fdim(-5,-6) == 1 */
+  TESTIT2 (fdim, -6.0, -5.0, 0.0); /* fdim(-6,-5) == 0 */
+
   TESTIT2 (fmin, 5.0, 6.0, 5.0); /* fmin(5,6) == 5 */
   TESTIT2 (fmin, 6.0, 5.0, 5.0); /* fmin(6,5) == 5 */
   TESTIT2 (fmin, -5.0, -6.0, -6.0); /* fmin(-5,-6) == -6 */