harmonize with dmc++ back end
Fix Issue 12873 - Valgrind unhandled instruction bytes 0x48 0xDB (redundant REX_W prefix on x87 load)
Fix Issue 10054 - x86_64 valgrind reports unrecognised instruction (DMD 2.062)
Issue 12852 - 64 bit wrong code generated

Conflicts:
	test/runnable/testxmm.d
fix Issue 12852 - 64 bit wrong code generated
Merge pull request #3622 from WalterBright/fix12855

fix Issue 12855 - Shadow register assignments for spilling can conflict
Merge pull request #3653 from WalterBright/cond-noret

reduce # of special cases for noreturn
fix pull #3620
add some array bounds check optimizations
bring up to date
fix
Issue 12933 - [D1] ICE with default __FILE__ and __LINE__
add -v2 switch
add -v2 check for octal literals
for root modules only
refactor extern(Windows) on 64 bit Windows to make clear it has C linkage
Merge pull request #3681 from ibuclaw/dwopaddr

DWARF: Emit address of __gshared variable correctly on I64
[-v2] check for default statement
[-v2] check for case fall-through
[-v2] require ; after do-while
[-v2] parentheses after invariant