[X86] Tune LEA usage for Silvermont

According to Intel Software Optimization Manual on Silvermont in some cases LEA
is better to be replaced with ADD instructions:
"The rule of thumb for ADDs and LEAs is that it is justified to use LEA
with a valid index and/or displacement for non-destructive destination purposes
(especially useful for stack offset cases), or to use a SCALE.
Otherwise, ADD(s) are preferable."

Differential Revision: http://reviews.llvm.org/D3826


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209198 91177308-0d34-0410-b5e6-96231b3b80d8
TableGen: convert InstAlias's Emit bit to an int.

When multiple aliases overlap, the correct string to print can often be
determined purely by considering the InstAlias declarations in some particular
order. This allows the user to specify that order manually when desired,
without resorting to hacking around with the default lexicographical order on
Record instantiation, which is error-prone and ugly.

I was also mistaken about "add w2, w3, w4" being the same as "add w2, w3, w4,
uxtw". That's only true if Rn is the stack pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209199 91177308-0d34-0410-b5e6-96231b3b80d8
ARMEB: Additional test files for ARM fixups

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209200 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Add more relocation types and MIPS specific e_flags constants.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209201 91177308-0d34-0410-b5e6-96231b3b80d8
Legalizer: Make bswap promotion safe for vectors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209202 91177308-0d34-0410-b5e6-96231b3b80d8