[binutils-gdb] Extend rl78 prologue analyzer to recognize more complicated prologues

[sergiodj+buildbot at redhat dot com]

*** TEST RESULTS FOR COMMIT 0bca7f99d8fa254b5e35a211ee306a46b95adc65 ***

Author: Kevin Buettner <kevinb@redhat.com>
Branch: master
Commit: 0bca7f99d8fa254b5e35a211ee306a46b95adc65

Extend rl78 prologue analyzer to recognize more complicated prologues
This patch extends the rl78 prologue analyzer so that it can recognize
this kind of prologue:

   0x119f <main>:       movw    ax, sp
   0x11a1 <main+2>:     subw    ax, #0x1fa6
   0x11a4 <main+5>:     movw    sp, ax

The test case for gdb.base/miscexprs.exp is now compiled to generate
that sequence instead of a much longer and more inefficient sequence.

gdb/ChangeLog:

	* rl78-tdep.c (RL78_SP_ADDR): Define.
	(opc_reg_to_gdb_regnum): New static function.
	(rl78_analyze_prologue): Recognize instructions forming slightly
	more interesting prologues.