diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 03f566c2cd9..1b9985af4da 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2015-09-29  Jeff Law  <law@redhat.com>
+
+	* config/msp430/msp430.c (msp430_legitimate_constant): Fix undefined
+	left shift behaviour.
+	* config/msp430/constraints.md ('L' constraint): Similarly.
+	('Ys' constraint): Similarly.
+
 2015-09-29  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/67170
diff --git a/gcc/config/msp430/constraints.md b/gcc/config/msp430/constraints.md
index 30f944c790e..dfda1528a04 100644
--- a/gcc/config/msp430/constraints.md
+++ b/gcc/config/msp430/constraints.md
@@ -32,7 +32,7 @@
 (define_constraint "L"
   "Integer constant -1^20..1^19."
   (and (match_code "const_int")
-       (match_test "IN_RANGE (ival, -1 << 20, 1 << 19)")))
+       (match_test "IN_RANGE (ival, HOST_WIDE_INT_M1U << 20, 1 << 19)")))
 
 (define_constraint "M"
   "Integer constant 1-4."
@@ -77,7 +77,7 @@
 	(and (match_code "plus" "0")
 	     (and (match_code "reg" "00")
 		  (match_test ("CONST_INT_P (XEXP (XEXP (op, 0), 1))"))
-		  (match_test ("IN_RANGE (INTVAL (XEXP (XEXP (op, 0), 1)), -1 << 15, (1 << 15)-1)"))))
+		  (match_test ("IN_RANGE (INTVAL (XEXP (XEXP (op, 0), 1)), HOST_WIDE_INT_M1U << 15, (1 << 15)-1)"))))
 	(match_code "reg" "0")
 	)))
 
diff --git a/gcc/config/msp430/msp430.c b/gcc/config/msp430/msp430.c
index d2308cb064d..ba8d8628846 100644
--- a/gcc/config/msp430/msp430.c
+++ b/gcc/config/msp430/msp430.c
@@ -998,7 +998,7 @@ msp430_legitimate_constant (machine_mode mode, rtx x)
     /* GCC does not know the width of the PSImode, so make
        sure that it does not try to use a constant value that
        is out of range.  */
-    || (INTVAL (x) < (1 << 20) && INTVAL (x) >= (-1 << 20));
+    || (INTVAL (x) < (1 << 20) && INTVAL (x) >= (HOST_WIDE_INT)(HOST_WIDE_INT_M1U << 20));
 }