diff --git a/gdb/defs.h b/gdb/defs.h
index a0b586f401eca205334e9f237081f4da97c83aa1..a1a97bb1e791d4f423788797d1f04c3e89877d90 100644
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -658,7 +658,10 @@ extern void store_unsigned_integer (gdb_byte *, int,
 extern void store_typed_address (gdb_byte *buf, struct type *type,
 				 CORE_ADDR addr);

-

+extern void copy_integer_to_size (gdb_byte *dest, int dest_size,
+				  const gdb_byte *source, int source_size,
+				  bool is_signed, enum bfd_endian byte_order);
+
 /* From valops.c */

 extern int watchdog;
diff --git a/gdb/findvar.c b/gdb/findvar.c
index ed4d5c1266c9de069981b306bc8229ae5fb02350..6c18e25fe2e28214de5acf571ebb3e45bf694d95 100644
--- a/gdb/findvar.c
+++ b/gdb/findvar.c
@@ -33,6 +33,7 @@
 #include "objfiles.h"
 #include "language.h"
 #include "dwarf2loc.h"
+#include "selftest.h"

 /* Basic byte-swapping routines.  All 'extract' functions return a
    host-format integer from a target-format integer at ADDR which is
@@ -249,7 +250,46 @@ store_typed_address (gdb_byte *buf, struct type *type, CORE_ADDR addr)
   gdbarch_address_to_pointer (get_type_arch (type), type, buf, addr);
 }

+/* Copy a value from SOURCE of size SOURCE_SIZE bytes to DEST of size DEST_SIZE
+   bytes.  If SOURCE_SIZE is greater than DEST_SIZE, then truncate the most
+   significant bytes.  If SOURCE_SIZE is less than DEST_SIZE then either sign
+   or zero extended according to IS_SIGNED.  Values are stored in memory with
+   endianess BYTE_ORDER.  */

+void
+copy_integer_to_size (gdb_byte *dest, int dest_size, const gdb_byte *source,
+		      int source_size, bool is_signed,
+		      enum bfd_endian byte_order)
+{
+  signed int size_diff = dest_size - source_size;
+
+  /* Copy across everything from SOURCE that can fit into DEST.  */
+
+  if (byte_order == BFD_ENDIAN_BIG && size_diff > 0)
+    memcpy (dest + size_diff, source, source_size);
+  else if (byte_order == BFD_ENDIAN_BIG && size_diff < 0)
+    memcpy (dest, source - size_diff, dest_size);
+  else
+    memcpy (dest, source, std::min (source_size, dest_size));
+
+  /* Fill the remaining space in DEST by either zero extending or sign
+     extending.  */
+
+  if (size_diff > 0)
+    {
+      gdb_byte extension = 0;
+      if (is_signed
+	  && ((byte_order != BFD_ENDIAN_BIG && source[source_size - 1] & 0x80)
+	      || (byte_order == BFD_ENDIAN_BIG && source[0] & 0x80)))
+	extension = 0xff;
+
+      /* Extend into MSBs of SOURCE.  */
+      if (byte_order == BFD_ENDIAN_BIG)
+	memset (dest, extension, size_diff);
+      else
+	memset (dest + source_size, extension, size_diff);
+    }
+}

 /* Return a `value' with the contents of (virtual or cooked) register
    REGNUM as found in the specified FRAME.  The register's type is
@@ -1005,3 +1045,91 @@ address_from_register (int regnum, struct frame_info *frame)
   return result;
 }

+#if GDB_SELF_TEST
+namespace selftests {
+namespace findvar_tests {
+
+/* Function to test copy_integer_to_size.  Store SOURCE_VAL with size
+   SOURCE_SIZE to a buffer, making sure no sign extending happens at this
+   stage.  Copy buffer to a new buffer using copy_integer_to_size.  Extract
+   copied value and compare to DEST_VALU.  Copy again with a signed
+   copy_integer_to_size and compare to DEST_VALS.  Do everything for both
+   LITTLE and BIG target endians.  Use unsigned values throughout to make
+   sure there are no implicit sign extensions.  */
+
+static void
+do_cint_test (ULONGEST dest_valu, ULONGEST dest_vals, int dest_size,
+	      ULONGEST src_val, int src_size)
+{
+  for (int i = 0; i < 2 ; i++)
+    {
+      gdb_byte srcbuf[sizeof (ULONGEST)] = {};
+      gdb_byte destbuf[sizeof (ULONGEST)] = {};
+      enum bfd_endian byte_order = i ? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE;
+
+      /* Fill the src buffer (and later the dest buffer) with non-zero junk,
+	 to ensure zero extensions aren't hidden.  */
+      memset (srcbuf, 0xaa, sizeof (srcbuf));
+
+      /* Store (and later extract) using unsigned to ensure there are no sign
+	 extensions.  */
+      store_unsigned_integer (srcbuf, src_size, byte_order, src_val);
+
+      /* Test unsigned.  */
+      memset (destbuf, 0xaa, sizeof (destbuf));
+      copy_integer_to_size (destbuf, dest_size, srcbuf, src_size, false,
+			    byte_order);
+      SELF_CHECK (dest_valu == extract_unsigned_integer (destbuf, dest_size,
+							 byte_order));
+
+      /* Test signed.  */
+      memset (destbuf, 0xaa, sizeof (destbuf));
+      copy_integer_to_size (destbuf, dest_size, srcbuf, src_size, true,
+			    byte_order);
+      SELF_CHECK (dest_vals == extract_unsigned_integer (destbuf, dest_size,
+							 byte_order));
+    }
+}
+
+static void
+copy_integer_to_size_test ()
+{
+  /* Destination is bigger than the source, which has the signed bit unset.  */
+  do_cint_test (0x12345678, 0x12345678, 8, 0x12345678, 4);
+  do_cint_test (0x345678, 0x345678, 8, 0x12345678, 3);
+
+  /* Destination is bigger than the source, which has the signed bit set.  */
+  do_cint_test (0xdeadbeef, 0xffffffffdeadbeef, 8, 0xdeadbeef, 4);
+  do_cint_test (0xadbeef, 0xffffffffffadbeef, 8, 0xdeadbeef, 3);
+
+  /* Destination is smaller than the source.  */
+  do_cint_test (0x5678, 0x5678, 2, 0x12345678, 3);
+  do_cint_test (0xbeef, 0xbeef, 2, 0xdeadbeef, 3);
+
+  /* Destination and source are the same size.  */
+  do_cint_test (0x8765432112345678, 0x8765432112345678, 8, 0x8765432112345678,
+		8);
+  do_cint_test (0x432112345678, 0x432112345678, 6, 0x8765432112345678, 6);
+  do_cint_test (0xfeedbeaddeadbeef, 0xfeedbeaddeadbeef, 8, 0xfeedbeaddeadbeef,
+		8);
+  do_cint_test (0xbeaddeadbeef, 0xbeaddeadbeef, 6, 0xfeedbeaddeadbeef, 6);
+
+  /* Destination is bigger than the source.  Source is bigger than 32bits.  */
+  do_cint_test (0x3412345678, 0x3412345678, 8, 0x3412345678, 6);
+  do_cint_test (0xff12345678, 0xff12345678, 8, 0xff12345678, 6);
+  do_cint_test (0x432112345678, 0x432112345678, 8, 0x8765432112345678, 6);
+  do_cint_test (0xff2112345678, 0xffffff2112345678, 8, 0xffffff2112345678, 6);
+}
+
+} // namespace findvar_test
+} // namespace selftests
+
+#endif
+
+void
+_initialize_findvar (void)
+{
+#if GDB_SELF_TEST
+  register_self_test (selftests::findvar_tests::copy_integer_to_size_test);
+#endif
+}
diff --git a/gdb/mips-fbsd-tdep.c b/gdb/mips-fbsd-tdep.c
index 00fae0ec60ddc9e645d3236efe29f2f9e9ceab5c..13cf98585f96f1acfe6decbe320530d609bee646 100644
--- a/gdb/mips-fbsd-tdep.c
+++ b/gdb/mips-fbsd-tdep.c
@@ -47,57 +47,24 @@
    34th is a dummy for padding.  */
 #define MIPS_FBSD_NUM_FPREGS	34

-/* Supply a single register.  If the source register size matches the
-   size the regcache expects, this can use regcache_raw_supply().  If
-   they are different, this copies the source register into a buffer
-   that can be passed to regcache_raw_supply().  */
+/* Supply a single register.  The register size might not match, so use
+   regcache->raw_supply_integer ().  */

 static void
 mips_fbsd_supply_reg (struct regcache *regcache, int regnum, const void *addr,
 		      size_t len)
 {
-  struct gdbarch *gdbarch = get_regcache_arch (regcache);
-
-  if (register_size (gdbarch, regnum) == len)
-    regcache_raw_supply (regcache, regnum, addr);
-  else
-    {
-      enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-      gdb_byte buf[MAX_REGISTER_SIZE];
-      LONGEST val;
-
-      val = extract_signed_integer ((const gdb_byte *) addr, len, byte_order);
-      store_signed_integer (buf, register_size (gdbarch, regnum), byte_order,
-			    val);
-      regcache_raw_supply (regcache, regnum, buf);
-    }
+  regcache->raw_supply_integer (regnum, (const gdb_byte *) addr, len, true);
 }

-/* Collect a single register.  If the destination register size
-   matches the size the regcache expects, this can use
-   regcache_raw_supply().  If they are different, this fetches the
-   register via regcache_raw_supply() into a buffer and then copies it
-   into the final destination.  */
+/* Collect a single register.  The register size might not match, so use
+   regcache->raw_collect_integer ().  */

 static void
 mips_fbsd_collect_reg (const struct regcache *regcache, int regnum, void *addr,
 		       size_t len)
 {
-  struct gdbarch *gdbarch = get_regcache_arch (regcache);
-
-  if (register_size (gdbarch, regnum) == len)
-    regcache_raw_collect (regcache, regnum, addr);
-  else
-    {
-      enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-      gdb_byte buf[MAX_REGISTER_SIZE];
-      LONGEST val;
-
-      regcache_raw_collect (regcache, regnum, buf);
-      val = extract_signed_integer (buf, register_size (gdbarch, regnum),
-				    byte_order);
-      store_signed_integer ((gdb_byte *) addr, len, byte_order, val);
-    }
+  regcache->raw_collect_integer (regnum, (gdb_byte *) addr, len, true);
 }

 /* Supply the floating-point registers stored in FPREGS to REGCACHE.
diff --git a/gdb/mips-linux-tdep.c b/gdb/mips-linux-tdep.c
index 48a582a16c934abe6e8f87c46a6009649c606d49..ccfdcdf98bc1e528cd768efaaaffaa3405708f71 100644
--- a/gdb/mips-linux-tdep.c
+++ b/gdb/mips-linux-tdep.c
@@ -116,13 +116,7 @@ mips_linux_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
 static void
 supply_32bit_reg (struct regcache *regcache, int regnum, const void *addr)
 {
-  struct gdbarch *gdbarch = get_regcache_arch (regcache);
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  gdb_byte buf[MAX_REGISTER_SIZE];
-  store_signed_integer (buf, register_size (gdbarch, regnum), byte_order,
-			extract_signed_integer ((const gdb_byte *) addr, 4,
-						byte_order));
-  regcache_raw_supply (regcache, regnum, buf);
+  regcache->raw_supply_integer (regnum, (const gdb_byte *) addr, 4, true);
 }

 /* Unpack an elf_gregset_t into GDB's register cache.  */
@@ -417,7 +411,6 @@ mips64_fill_gregset (const struct regcache *regcache,
 		     mips64_elf_gregset_t *gregsetp, int regno)
 {
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int regaddr, regi;
   mips64_elf_greg_t *regp = *gregsetp;
   void *dst;
@@ -460,14 +453,8 @@ mips64_fill_gregset (const struct regcache *regcache,

   if (regaddr != -1)
     {
-      gdb_byte buf[MAX_REGISTER_SIZE];
-      LONGEST val;
-
-      regcache_raw_collect (regcache, regno, buf);
-      val = extract_signed_integer (buf, register_size (gdbarch, regno),
-				    byte_order);
       dst = regp + regaddr;
-      store_signed_integer ((gdb_byte *) dst, 8, byte_order, val);
+      regcache->raw_collect_integer (regno, (gdb_byte *) dst, 8, true);
     }
 }

@@ -564,25 +551,13 @@ mips64_fill_fpregset (const struct regcache *regcache,
     }
   else if (regno == mips_regnum (gdbarch)->fp_control_status)
     {
-      gdb_byte buf[MAX_REGISTER_SIZE];
-      LONGEST val;
-
-      regcache_raw_collect (regcache, regno, buf);
-      val = extract_signed_integer (buf, register_size (gdbarch, regno),
-				    byte_order);
       to = (gdb_byte *) (*fpregsetp + 32);
-      store_signed_integer (to, 4, byte_order, val);
+      regcache->raw_collect_integer (regno, to, 4, true);
     }
   else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
     {
-      gdb_byte buf[MAX_REGISTER_SIZE];
-      LONGEST val;
-
-      regcache_raw_collect (regcache, regno, buf);
-      val = extract_signed_integer (buf, register_size (gdbarch, regno),
-				    byte_order);
       to = (gdb_byte *) (*fpregsetp + 32) + 4;
-      store_signed_integer (to, 4, byte_order, val);
+      regcache->raw_collect_integer (regno, to, 4, true);
     }
   else if (regno == -1)
     {
diff --git a/gdb/regcache.h b/gdb/regcache.h
index 4dcfccbac70f0f962bf5e5596d035fda42322795..409482d17c0542c7a53620d88d33fa9706fa72c5 100644
--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -294,8 +294,14 @@ public:

   void raw_collect (int regnum, void *buf) const;

+  void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
+			    bool is_signed) const;
+
   void raw_supply (int regnum, const void *buf);

+  void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
+			   bool is_signed);
+
   void raw_supply_zeroed (int regnum);

   void raw_copy (int regnum, struct regcache *src_regcache);
diff --git a/gdb/regcache.c b/gdb/regcache.c
index 660558f7ff10f9d8346b6e08422e16c38c3c4d7d..90462aea73ba810bd1af9ddb8c6d02e1f0e95991 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -1189,6 +1189,31 @@ regcache::raw_supply (int regnum, const void *buf)
     }
 }

+/* Supply register REGNUM to REGCACHE.  Value to supply is an integer stored at
+   address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.  If
+   the register size is greater than ADDR_LEN, then the integer will be sign or
+   zero extended.  If the register size is smaller than the integer, then the
+   most significant bytes of the integer will be truncated.  */
+
+void
+regcache::raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
+			      bool is_signed)
+{
+  enum bfd_endian byte_order = gdbarch_byte_order (m_descr->gdbarch);
+  gdb_byte *regbuf;
+  size_t regsize;
+
+  gdb_assert (regnum >= 0 && regnum < m_descr->nr_raw_registers);
+  gdb_assert (!m_readonly_p);
+
+  regbuf = register_buffer (regnum);
+  regsize = m_descr->sizeof_register[regnum];
+
+  copy_integer_to_size (regbuf, regsize, addr, addr_len, is_signed,
+			byte_order);
+  m_register_status[regnum] = REG_VALID;
+}
+
 /* Supply register REGNUM with zeroed value to REGCACHE.  This is not the same
    as calling raw_supply with NULL (which will set the state to
    unavailable).  */
@@ -1232,6 +1257,29 @@ regcache::raw_collect (int regnum, void *buf) const
   memcpy (buf, regbuf, size);
 }

+/* Collect register REGNUM from REGCACHE.  Store collected value as an integer
+   at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
+   If ADDR_LEN is greater than the register size, then the integer will be sign
+   or zero extended.  If ADDR_LEN is smaller than the register size, then the
+   most significant bytes of the integer will be truncated.  */
+
+void
+regcache::raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
+			       bool is_signed) const
+{
+  enum bfd_endian byte_order = gdbarch_byte_order (m_descr->gdbarch);
+  const gdb_byte *regbuf;
+  size_t regsize;
+
+  gdb_assert (regnum >= 0 && regnum < m_descr->nr_raw_registers);
+
+  regbuf = register_buffer (regnum);
+  regsize = m_descr->sizeof_register[regnum];
+
+  copy_integer_to_size (addr, addr_len, regbuf, regsize, is_signed,
+			byte_order);
+}
+
 void
 regcache::raw_copy (int regnum, struct regcache *src_regcache)
 {
