diff --git a/src/cmd/gc/builtin.c.boot b/src/cmd/gc/builtin.c.boot
index 7659ac5..95098c8 100644
--- a/src/cmd/gc/builtin.c.boot
+++ b/src/cmd/gc/builtin.c.boot
@@ -103,9 +103,9 @@
 	"package unsafe\n"
 	"import runtime \"runtime\"\n"
 	"type \"\".Pointer uintptr\n"
-	"func \"\".Offsetof (? any) int\n"
-	"func \"\".Sizeof (? any) int\n"
-	"func \"\".Alignof (? any) int\n"
+	"func \"\".Offsetof (? any) uintptr\n"
+	"func \"\".Sizeof (? any) uintptr\n"
+	"func \"\".Alignof (? any) uintptr\n"
 	"func \"\".Typeof (i interface { }) interface { }\n"
 	"func \"\".Reflect (i interface { }) (typ interface { }, addr \"\".Pointer)\n"
 	"func \"\".Unreflect (typ interface { }, addr \"\".Pointer) interface { }\n"
diff --git a/src/cmd/gc/unsafe.c b/src/cmd/gc/unsafe.c
index 540994d..d304077 100644
--- a/src/cmd/gc/unsafe.c
+++ b/src/cmd/gc/unsafe.c
@@ -92,6 +92,6 @@
 	mpmovecfix(val.u.xval, v);
 	n = nod(OLITERAL, N, N);
 	n->val = val;
-	n->type = types[TINT];
+	n->type = types[TUINTPTR];
 	return n;
 }
diff --git a/src/cmd/gc/unsafe.go b/src/cmd/gc/unsafe.go
index b2a341d..db27d74 100644
--- a/src/cmd/gc/unsafe.go
+++ b/src/cmd/gc/unsafe.go
@@ -10,9 +10,11 @@
 
 type Pointer uintptr // not really; filled in by compiler
 
-func Offsetof(any) int
-func Sizeof(any) int
-func Alignof(any) int
+// return types here are ignored; see unsafe.c
+func Offsetof(any) uintptr
+func Sizeof(any) uintptr
+func Alignof(any) uintptr
+
 func Typeof(i interface{}) (typ interface{})
 func Reflect(i interface{}) (typ interface{}, addr Pointer)
 func Unreflect(typ interface{}, addr Pointer) (ret interface{})
diff --git a/src/pkg/gob/decode.go b/src/pkg/gob/decode.go
index 381d44c..f56d72a 100644
--- a/src/pkg/gob/decode.go
+++ b/src/pkg/gob/decode.go
@@ -367,7 +367,7 @@
 		p = *(*unsafe.Pointer)(p)
 	}
 	storeFloat32(i, state, p)
-	storeFloat32(i, state, unsafe.Pointer(uintptr(p)+uintptr(unsafe.Sizeof(float32(0)))))
+	storeFloat32(i, state, unsafe.Pointer(uintptr(p)+unsafe.Sizeof(float32(0))))
 }
 
 // decComplex128 decodes a pair of unsigned integers, treats them as a
diff --git a/src/pkg/gob/encode.go b/src/pkg/gob/encode.go
index f9e691a..743e853 100644
--- a/src/pkg/gob/encode.go
+++ b/src/pkg/gob/encode.go
@@ -11,7 +11,7 @@
 	"unsafe"
 )
 
-const uint64Size = unsafe.Sizeof(uint64(0))
+const uint64Size = int(unsafe.Sizeof(uint64(0)))
 
 // encoderState is the global execution state of an instance of the encoder.
 // Field numbers are delta encoded and always increase. The field
diff --git a/src/pkg/hash/fnv/fnv.go b/src/pkg/hash/fnv/fnv.go
index 9a1c6a0..3ff7d7c 100644
--- a/src/pkg/hash/fnv/fnv.go
+++ b/src/pkg/hash/fnv/fnv.go
@@ -11,7 +11,6 @@
 	"encoding/binary"
 	"hash"
 	"os"
-	"unsafe"
 )
 
 type (
@@ -102,31 +101,31 @@
 	return len(data), nil
 }
 
-func (s *sum32) Size() int  { return unsafe.Sizeof(*s) }
-func (s *sum32a) Size() int { return unsafe.Sizeof(*s) }
-func (s *sum64) Size() int  { return unsafe.Sizeof(*s) }
-func (s *sum64a) Size() int { return unsafe.Sizeof(*s) }
+func (s *sum32) Size() int  { return 4 }
+func (s *sum32a) Size() int { return 4 }
+func (s *sum64) Size() int  { return 8 }
+func (s *sum64a) Size() int { return 8 }
 
 func (s *sum32) Sum() []byte {
-	a := make([]byte, unsafe.Sizeof(*s))
+	a := make([]byte, 4)
 	binary.BigEndian.PutUint32(a, uint32(*s))
 	return a
 }
 
 func (s *sum32a) Sum() []byte {
-	a := make([]byte, unsafe.Sizeof(*s))
+	a := make([]byte, 4)
 	binary.BigEndian.PutUint32(a, uint32(*s))
 	return a
 }
 
 func (s *sum64) Sum() []byte {
-	a := make([]byte, unsafe.Sizeof(*s))
+	a := make([]byte, 8)
 	binary.BigEndian.PutUint64(a, uint64(*s))
 	return a
 }
 
 func (s *sum64a) Sum() []byte {
-	a := make([]byte, unsafe.Sizeof(*s))
+	a := make([]byte, 8)
 	binary.BigEndian.PutUint64(a, uint64(*s))
 	return a
 }
diff --git a/src/pkg/reflect/type.go b/src/pkg/reflect/type.go
index aef6370..6c1ab60 100644
--- a/src/pkg/reflect/type.go
+++ b/src/pkg/reflect/type.go
@@ -827,7 +827,7 @@
 		i  runtime.Type
 		ct commonType
 	}
-	return (*runtime.Type)(unsafe.Pointer(uintptr(unsafe.Pointer(t)) - uintptr(unsafe.Offsetof(rt.ct))))
+	return (*runtime.Type)(unsafe.Pointer(uintptr(unsafe.Pointer(t)) - unsafe.Offsetof(rt.ct)))
 }
 
 // PtrTo returns the pointer type with element t.
@@ -888,7 +888,7 @@
 
 	p.uncommonType = nil
 	p.ptrToThis = nil
-	p.elem = (*runtime.Type)(unsafe.Pointer(uintptr(unsafe.Pointer(ct)) - uintptr(unsafe.Offsetof(rt.ptrType))))
+	p.elem = (*runtime.Type)(unsafe.Pointer(uintptr(unsafe.Pointer(ct)) - unsafe.Offsetof(rt.ptrType)))
 
 	ptrMap.m[ct] = p
 	ptrMap.Unlock()
diff --git a/src/pkg/reflect/value.go b/src/pkg/reflect/value.go
index 3abe13e..b1999aa 100644
--- a/src/pkg/reflect/value.go
+++ b/src/pkg/reflect/value.go
@@ -11,7 +11,7 @@
 	"unsafe"
 )
 
-const ptrSize = uintptr(unsafe.Sizeof((*byte)(nil)))
+const ptrSize = unsafe.Sizeof((*byte)(nil))
 const cannotSet = "cannot set value obtained from unexported struct field"
 
 // TODO: This will have to go away when
diff --git a/src/pkg/runtime/malloc.goc b/src/pkg/runtime/malloc.goc
index c55be97..49ab24d 100644
--- a/src/pkg/runtime/malloc.goc
+++ b/src/pkg/runtime/malloc.goc
@@ -229,7 +229,7 @@
 	return c;
 }
 
-int32 runtime·sizeof_C_MStats = sizeof(MStats);
+uintptr runtime·sizeof_C_MStats = sizeof(MStats);
 
 #define MaxArena32 (2U<<30)
 
diff --git a/src/pkg/runtime/mem.go b/src/pkg/runtime/mem.go
index fe505a3..c3316d4 100644
--- a/src/pkg/runtime/mem.go
+++ b/src/pkg/runtime/mem.go
@@ -52,7 +52,7 @@
 	}
 }
 
-var sizeof_C_MStats int // filled in by malloc.goc
+var sizeof_C_MStats uintptr // filled in by malloc.goc
 
 func init() {
 	if sizeof_C_MStats != unsafe.Sizeof(MemStats) {
diff --git a/src/pkg/runtime/pprof/pprof_test.go b/src/pkg/runtime/pprof/pprof_test.go
index a060917..4486d55 100644
--- a/src/pkg/runtime/pprof/pprof_test.go
+++ b/src/pkg/runtime/pprof/pprof_test.go
@@ -43,7 +43,7 @@
 	// Convert []byte to []uintptr.
 	bytes := prof.Bytes()
 	val := *(*[]uintptr)(unsafe.Pointer(&bytes))
-	val = val[:len(bytes)/unsafe.Sizeof(uintptr(0))]
+	val = val[:len(bytes)/int(unsafe.Sizeof(uintptr(0)))]
 
 	if len(val) < 10 {
 		t.Fatalf("profile too short: %#x", val)
diff --git a/src/pkg/syscall/exec_unix.go b/src/pkg/syscall/exec_unix.go
index a6ac398..4b3cfe4 100644
--- a/src/pkg/syscall/exec_unix.go
+++ b/src/pkg/syscall/exec_unix.go
@@ -249,7 +249,7 @@
 
 childerror:
 	// send error code on pipe
-	RawSyscall(SYS_WRITE, uintptr(pipe), uintptr(unsafe.Pointer(&err1)), uintptr(unsafe.Sizeof(err1)))
+	RawSyscall(SYS_WRITE, uintptr(pipe), uintptr(unsafe.Pointer(&err1)), unsafe.Sizeof(err1))
 	for {
 		RawSyscall(SYS_EXIT, 253, 0, 0)
 	}
@@ -343,10 +343,10 @@
 
 	// Read child error status from pipe.
 	Close(p[1])
-	n, err = read(p[0], (*byte)(unsafe.Pointer(&err1)), unsafe.Sizeof(err1))
+	n, err = read(p[0], (*byte)(unsafe.Pointer(&err1)), int(unsafe.Sizeof(err1)))
 	Close(p[0])
 	if err != 0 || n != 0 {
-		if n == unsafe.Sizeof(err1) {
+		if n == int(unsafe.Sizeof(err1)) {
 			err = int(err1)
 		}
 		if err == 0 {
diff --git a/src/pkg/syscall/syscall_bsd.go b/src/pkg/syscall/syscall_bsd.go
index 89bcc7f..321d9d3 100644
--- a/src/pkg/syscall/syscall_bsd.go
+++ b/src/pkg/syscall/syscall_bsd.go
@@ -155,7 +155,7 @@
 //sys	connect(s int, addr uintptr, addrlen _Socklen) (errno int)
 //sysnb	socket(domain int, typ int, proto int) (fd int, errno int)
 //sys	getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (errno int)
-//sys	setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int)
+//sys	setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int)
 //sysnb	getpeername(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (errno int)
 //sysnb	getsockname(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (errno int)
 //sys	Shutdown(s int, how int) (errno int)
@@ -451,7 +451,7 @@
 
 // Translate "kern.hostname" to []_C_int{0,1,2,3}.
 func nametomib(name string) (mib []_C_int, errno int) {
-	const siz = uintptr(unsafe.Sizeof(mib[0]))
+	const siz = unsafe.Sizeof(mib[0])
 
 	// NOTE(rsc): It seems strange to set the buffer to have
 	// size CTL_MAXNAME+2 but use only CTL_MAXNAME
diff --git a/src/pkg/syscall/syscall_linux.go b/src/pkg/syscall/syscall_linux.go
index 63682d2..3b8f36d 100644
--- a/src/pkg/syscall/syscall_linux.go
+++ b/src/pkg/syscall/syscall_linux.go
@@ -472,7 +472,7 @@
 }
 
 func SetsockoptString(fd, level, opt int, s string) (errno int) {
-	return setsockopt(fd, level, opt, uintptr(unsafe.Pointer(&[]byte(s)[0])), len(s))
+	return setsockopt(fd, level, opt, uintptr(unsafe.Pointer(&[]byte(s)[0])), uintptr(len(s)))
 }
 
 func Recvfrom(fd int, p []byte, flags int) (n int, from Sockaddr, errno int) {
diff --git a/src/pkg/syscall/syscall_linux_386.go b/src/pkg/syscall/syscall_linux_386.go
index 5195179..44891de 100644
--- a/src/pkg/syscall/syscall_linux_386.go
+++ b/src/pkg/syscall/syscall_linux_386.go
@@ -146,8 +146,8 @@
 	return
 }
 
-func setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int) {
-	_, errno = socketcall(_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(vallen), 0)
+func setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int) {
+	_, errno = socketcall(_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), val, vallen, 0)
 	return
 }
 
@@ -190,13 +190,13 @@
 }
 
 func Fstatfs(fd int, buf *Statfs_t) (errno int) {
-	_, _, e1 := Syscall(SYS_FSTATFS64, uintptr(fd), uintptr(unsafe.Sizeof(*buf)), uintptr(unsafe.Pointer(buf)))
+	_, _, e1 := Syscall(SYS_FSTATFS64, uintptr(fd), unsafe.Sizeof(*buf), uintptr(unsafe.Pointer(buf)))
 	errno = int(e1)
 	return
 }
 
 func Statfs(path string, buf *Statfs_t) (errno int) {
-	_, _, e1 := Syscall(SYS_STATFS64, uintptr(unsafe.Pointer(StringBytePtr(path))), uintptr(unsafe.Sizeof(*buf)), uintptr(unsafe.Pointer(buf)))
+	_, _, e1 := Syscall(SYS_STATFS64, uintptr(unsafe.Pointer(StringBytePtr(path))), unsafe.Sizeof(*buf), uintptr(unsafe.Pointer(buf)))
 	errno = int(e1)
 	return
 }
diff --git a/src/pkg/syscall/syscall_linux_amd64.go b/src/pkg/syscall/syscall_linux_amd64.go
index db95246..8b206ad 100644
--- a/src/pkg/syscall/syscall_linux_amd64.go
+++ b/src/pkg/syscall/syscall_linux_amd64.go
@@ -42,7 +42,7 @@
 //sysnb	getgroups(n int, list *_Gid_t) (nn int, errno int)
 //sysnb	setgroups(n int, list *_Gid_t) (errno int)
 //sys	getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (errno int)
-//sys	setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int)
+//sys	setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int)
 //sysnb	socket(domain int, typ int, proto int) (fd int, errno int)
 //sysnb	socketpair(domain int, typ int, proto int, fd *[2]int) (errno int)
 //sysnb	getpeername(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (errno int)
diff --git a/src/pkg/syscall/syscall_linux_arm.go b/src/pkg/syscall/syscall_linux_arm.go
index 3784530..8c03c76 100644
--- a/src/pkg/syscall/syscall_linux_arm.go
+++ b/src/pkg/syscall/syscall_linux_arm.go
@@ -71,7 +71,7 @@
 //sysnb	getgroups(n int, list *_Gid_t) (nn int, errno int) = SYS_GETGROUPS32
 //sysnb	setgroups(n int, list *_Gid_t) (errno int) = SYS_SETGROUPS32
 //sys	getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (errno int)
-//sys	setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int)
+//sys	setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int)
 //sysnb	socket(domain int, typ int, proto int) (fd int, errno int)
 //sysnb	getpeername(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (errno int)
 //sysnb	getsockname(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (errno int)
diff --git a/src/pkg/syscall/zsyscall_darwin_386.go b/src/pkg/syscall/zsyscall_darwin_386.go
index 13a8ed0..bbaceee 100644
--- a/src/pkg/syscall/zsyscall_darwin_386.go
+++ b/src/pkg/syscall/zsyscall_darwin_386.go
@@ -85,7 +85,7 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int) {
+func setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int) {
 	_, _, e1 := Syscall6(SYS_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(vallen), 0)
 	errno = int(e1)
 	return
diff --git a/src/pkg/syscall/zsyscall_darwin_amd64.go b/src/pkg/syscall/zsyscall_darwin_amd64.go
index c671d71..ee39ead 100644
--- a/src/pkg/syscall/zsyscall_darwin_amd64.go
+++ b/src/pkg/syscall/zsyscall_darwin_amd64.go
@@ -85,7 +85,7 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int) {
+func setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int) {
 	_, _, e1 := Syscall6(SYS_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(vallen), 0)
 	errno = int(e1)
 	return
diff --git a/src/pkg/syscall/zsyscall_freebsd_386.go b/src/pkg/syscall/zsyscall_freebsd_386.go
index 0ffb9a4..4f7fdef 100644
--- a/src/pkg/syscall/zsyscall_freebsd_386.go
+++ b/src/pkg/syscall/zsyscall_freebsd_386.go
@@ -85,7 +85,7 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int) {
+func setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int) {
 	_, _, e1 := Syscall6(SYS_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(vallen), 0)
 	errno = int(e1)
 	return
diff --git a/src/pkg/syscall/zsyscall_freebsd_amd64.go b/src/pkg/syscall/zsyscall_freebsd_amd64.go
index 38a06ae..609ecdd 100644
--- a/src/pkg/syscall/zsyscall_freebsd_amd64.go
+++ b/src/pkg/syscall/zsyscall_freebsd_amd64.go
@@ -85,7 +85,7 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int) {
+func setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int) {
 	_, _, e1 := Syscall6(SYS_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(vallen), 0)
 	errno = int(e1)
 	return
diff --git a/src/pkg/syscall/zsyscall_linux_amd64.go b/src/pkg/syscall/zsyscall_linux_amd64.go
index d6e2879..fa20ff5 100644
--- a/src/pkg/syscall/zsyscall_linux_amd64.go
+++ b/src/pkg/syscall/zsyscall_linux_amd64.go
@@ -1169,7 +1169,7 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int) {
+func setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int) {
 	_, _, e1 := Syscall6(SYS_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(vallen), 0)
 	errno = int(e1)
 	return
diff --git a/src/pkg/syscall/zsyscall_linux_arm.go b/src/pkg/syscall/zsyscall_linux_arm.go
index af5f7c5..560a65b 100644
--- a/src/pkg/syscall/zsyscall_linux_arm.go
+++ b/src/pkg/syscall/zsyscall_linux_arm.go
@@ -895,7 +895,7 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func setsockopt(s int, level int, name int, val uintptr, vallen int) (errno int) {
+func setsockopt(s int, level int, name int, val uintptr, vallen uintptr) (errno int) {
 	_, _, e1 := Syscall6(SYS_SETSOCKOPT, uintptr(s), uintptr(level), uintptr(name), uintptr(val), uintptr(vallen), 0)
 	errno = int(e1)
 	return
diff --git a/test/sizeof.go b/test/sizeof.go
new file mode 100644
index 0000000..544e4c5
--- /dev/null
+++ b/test/sizeof.go
@@ -0,0 +1,23 @@
+// $G $D/$F.go
+
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "unsafe"
+
+type T struct {
+	X int
+}
+
+var t T
+
+func isUintptr(uintptr) {}
+
+func main() {
+	isUintptr(unsafe.Sizeof(t))
+	isUintptr(unsafe.Alignof(t))
+	isUintptr(unsafe.Offsetof(t.X))
+}