diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f284af0cbd1..33e23b916de 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2007-06-17  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR rtl-optimization/32366
+	* simplify-rtx.c (simplify_unary_operation_1) [FLOAT_TRUNCATE,
+	FLOAT_EXTEND]: Prevent non-scalar modes from entering
+	significand_size.
+
 2007-06-17  Kenneth Zadeck <zadeck@naturalbridge.com>
 
 	PR middle-end/32349
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index ade3968d0e6..9b27bbdbd70 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -700,10 +700,11 @@ simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op)
       /*  (float_truncate (float x)) is (float x)  */
       if (GET_CODE (op) == FLOAT
 	  && (flag_unsafe_math_optimizations
-	      || ((unsigned)significand_size (GET_MODE (op))
-		  >= (GET_MODE_BITSIZE (GET_MODE (XEXP (op, 0)))
-		      - num_sign_bit_copies (XEXP (op, 0),
-					     GET_MODE (XEXP (op, 0)))))))
+	      || (SCALAR_FLOAT_MODE_P (GET_MODE (op))
+		  && ((unsigned)significand_size (GET_MODE (op))
+		      >= (GET_MODE_BITSIZE (GET_MODE (XEXP (op, 0)))
+			  - num_sign_bit_copies (XEXP (op, 0),
+						 GET_MODE (XEXP (op, 0))))))))
 	return simplify_gen_unary (FLOAT, mode,
 				   XEXP (op, 0),
 				   GET_MODE (XEXP (op, 0)));
@@ -736,6 +737,7 @@ simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op)
           */
       if (GET_CODE (op) == FLOAT_EXTEND
 	  || (GET_CODE (op) == FLOAT
+	      && SCALAR_FLOAT_MODE_P (GET_MODE (op))
 	      && ((unsigned)significand_size (GET_MODE (op))
 		  >= (GET_MODE_BITSIZE (GET_MODE (XEXP (op, 0)))
 		      - num_sign_bit_copies (XEXP (op, 0),
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5b08f687091..96f6ff32d5f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-06-17  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR rtl-optimization/32366
+	* testsuite/gcc.dg/vect/pr32366.c: New test.
+
 2007-06-17  Kenneth Zadeck <zadeck@naturalbridge.com>
 
 	* gcc.c-torture/compile/pr32349.c: New testcase.
diff --git a/gcc/testsuite/gcc.dg/vect/pr32366.c b/gcc/testsuite/gcc.dg/vect/pr32366.c
new file mode 100644
index 00000000000..f4eb99fbca3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr32366.c
@@ -0,0 +1,13 @@
+/* Testcase by Martin Michlmayr <tbm@cyrius.com> */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_float } */
+
+stream_test (void)
+{
+  static float input[20];
+  int k;
+  for (k = 0; k < 20; k++)
+    input[k] = k * 1.0;
+}
+