diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e768519e5c2..aeb9d19f81b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2006-12-14  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/30198
+	* fold-const.c (fold_unary): Fold REALPART_EXPR of cexpi to cos.
+	Fold IMAGPART_EXPR of cexpi to sin.
+
 2006-12-14  Dorit Nuzman  <dorit@il.ibm.com>
 	    Trevor Smigiel  <trevor_smigiel@playstation.sony.com>
 
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index da1bfed173e..751ef2e6157 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -7715,6 +7715,19 @@ fold_unary (enum tree_code code, tree type, tree op0)
 	  tem = fold_build1 (REALPART_EXPR, itype, TREE_OPERAND (arg0, 0));
 	  return fold_convert (type, tem);
 	}
+      if (TREE_CODE (arg0) == CALL_EXPR)
+	{
+	  tree fn = get_callee_fndecl (arg0);
+	  if (DECL_BUILT_IN_CLASS (fn) == BUILT_IN_NORMAL)
+	    switch (DECL_FUNCTION_CODE (fn))
+	      {
+	      CASE_FLT_FN (BUILT_IN_CEXPI):
+	        fn = mathfn_built_in (type, BUILT_IN_COS);
+	        return build_function_call_expr (fn, TREE_OPERAND (arg0, 1));
+
+	      default:;
+	      }
+	}
       return NULL_TREE;
 
     case IMAGPART_EXPR:
@@ -7741,6 +7754,19 @@ fold_unary (enum tree_code code, tree type, tree op0)
 	  tem = fold_build1 (IMAGPART_EXPR, itype, TREE_OPERAND (arg0, 0));
 	  return fold_convert (type, negate_expr (tem));
 	}
+      if (TREE_CODE (arg0) == CALL_EXPR)
+	{
+	  tree fn = get_callee_fndecl (arg0);
+	  if (DECL_BUILT_IN_CLASS (fn) == BUILT_IN_NORMAL)
+	    switch (DECL_FUNCTION_CODE (fn))
+	      {
+	      CASE_FLT_FN (BUILT_IN_CEXPI):
+	        fn = mathfn_built_in (type, BUILT_IN_SIN);
+	        return build_function_call_expr (fn, TREE_OPERAND (arg0, 1));
+
+	      default:;
+	      }
+	}
       return NULL_TREE;
 
     default:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7ca23956e6b..b99415c9d8c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2006-12-14  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/30198
+	* gcc.dg/builtins-60.c: New testcase.
+
 2006-12-14  Dorit Nuzman  <dorit@il.ibm.com>
  
 	* lib/target-supports.exp (vect_no_align): Remove spu.
diff --git a/gcc/testsuite/gcc.dg/builtins-60.c b/gcc/testsuite/gcc.dg/builtins-60.c
new file mode 100644
index 00000000000..b57679f36eb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtins-60.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-gimple" } */
+
+double test1 (double x)
+{
+  return __real __builtin_cexpi (x);
+}
+
+double test2 (double x)
+{
+  return __imag __builtin_cexpi (x);
+}
+
+/* { dg-final { scan-tree-dump "cos" "gimple" } } */
+/* { dg-final { scan-tree-dump "sin" "gimple" } } */
+/* { dg-final { cleanup-tree-dump "gimple" } } */