Pull in r329771 from upstream llvm trunk (by Craig Topper):

[X86] In X86FlagsCopyLowering, when rewriting a memory setcc we need
to emit an explicit MOV8mr instruction.

Previously the code only knew how to handle setcc to a register.

This should fix a crash in the chromium build.

This fixes various assertion failures while building ports targeting
i386:

• www/firefox: isReg() && "This is not a register operand!"
• www/iridium, www/qt5-webengine: (I.atEnd() || std::next(I) == def_instr_end()) && "getVRegDef assumes a single definition or no definition"
• devel/powerpc64-gcc: FromReg != ToReg && "Cannot replace a reg with itself"

Reported by: jbeich
PR: 225330, 227686, 227698, 227699
MFC after: 1 week
X-MFC-With: r332833