diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b0b39a317421159a346e0bdd8101d679a8c69cc1..4c5dc8f206cc7d2387c7b85598ff92fb97b0064b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,7 +1,12 @@
+2006-02-07  Tobias Schlüter  <tobias.schlueter@physik.uni-muenchen.de>
+
+	PR fortran/25577
+	* gfortran.dg/mvbits_1.f90: New.
+
 2006-02-07  Dirk Mueller  <dmueller@suse.com>
 
-	g++.dg/warn/Wdiv-by-zero.C: New test.
-	g++.dg/warn/Wno-div-by-zero.C: New.
+	* g++.dg/warn/Wdiv-by-zero.C: New test.
+	* g++.dg/warn/Wno-div-by-zero.C: New.
 
 2006-02-07  Jeff Law  <law@redhat.com>
 
diff --git a/gcc/testsuite/gfortran.dg/mvbits_1.f90 b/gcc/testsuite/gfortran.dg/mvbits_1.f90
new file mode 100644
index 0000000000000000000000000000000000000000..90e92bb0e2654addaa5451eb87b93526394e4eb4
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/mvbits_1.f90
@@ -0,0 +1,39 @@
+! PR 25577
+! MVBITS didn't work correctly for integer types wider than a C int
+! The testcase is based on the one Dale Ranta posted in the bug report
+implicit none
+integer(1) i1,j1
+integer(2) i2,j2
+integer(4) i4,j4
+integer(8) i8,j8
+integer ibits,n
+
+ibits=bit_size(1_1)
+do n=1,ibits
+   i1=-1
+   call mvbits(1_1, 0,n,i1,0)
+   j1=-1-2_1**n+2
+   if(i1.ne.j1)call abort
+enddo
+ibits=bit_size(1_2)
+do n=1,ibits
+   i2=-1
+   call mvbits(1_2, 0,n,i2,0)
+   j2=-1-2_2**n+2
+   if(i2.ne.j2)call abort
+enddo
+ibits=bit_size(1_4)
+do n=1,ibits
+   i4=-1
+   call mvbits(1_4, 0,n,i4,0)
+   j4=-1-2_4**n+2
+   if(i4.ne.j4)call abort
+enddo
+ibits=bit_size(1_8)
+do n=1,ibits
+   i8=-1
+   call mvbits(1_8, 0,n,i8,0)
+   j8=-1-2_8**n+2
+   if(i8.ne.j8)call abort
+enddo
+end
diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index a48b5d800686689d6130acde77d9f533a84009df..8517787a1a770de5e4fd9ce085a4444a4719abc0 100644
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,8 @@
+2006-02-07  Dale Ranta  <dir@lanl.gov>
+
+	PR fortran/25577
+	* intrinsics/mvbits.c: Shift '(TYPE)1' type when building 'lenmask'.
+
 2006-02-07  Rainer Emrich <r.emrich@de.tecosim.com>
 
 	* intrinsics/c99_functions.c: Work around incompatible
diff --git a/libgfortran/intrinsics/mvbits.c b/libgfortran/intrinsics/mvbits.c
index 6bfb5cad85bf97e9d061d01f7195b9f5444e80b1..a452fc98b3f73fdec1719d4a96d3fe5f89ccf800 100644
--- a/libgfortran/intrinsics/mvbits.c
+++ b/libgfortran/intrinsics/mvbits.c
@@ -1,5 +1,5 @@
 /* Implementation of the MVBITS intrinsic
-   Copyright (C) 2004 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2006 Free Software Foundation, Inc.
    Contributed by Tobias Schlüter
 
 This file is part of the GNU Fortran 95 runtime library (libgfortran).
@@ -48,7 +48,7 @@ SUB_NAME (const TYPE *from, const GFC_INTEGER_4 *frompos,
 {
   TYPE oldbits, newbits, lenmask;
 
-  lenmask = (*len == sizeof (TYPE)*8) ? ~(TYPE)0 : (1 << *len) - 1;
+  lenmask = (*len == sizeof (TYPE)*8) ? ~(TYPE)0 : ((TYPE)1 << *len) - 1;
   newbits = (((UTYPE)(*from) >> *frompos) & lenmask) << *topos;
   oldbits = *to & (~(lenmask << *topos));