LLVMContext: Store APInt/APFloat directly into the ConstantInt/FP DenseMaps.

Required some APInt massaging to get proper empty/tombstone values. Apart
from making the code a bit simpler this also reduces the bucket size of
the ConstantInt map from 32 to 24 bytes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223478 91177308-0d34-0410-b5e6-96231b3b80d8
Be less conservative about when we build the gold plugin.

It is only build if LLVM_BINUTILS_INCDIR is explicitly given, so there is
no point in having extra restrictions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223481 91177308-0d34-0410-b5e6-96231b3b80d8
[Hexagon] Marking several instructions as isCodeGenOnly=0 and adding direct disassembly tests for many instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223482 91177308-0d34-0410-b5e6-96231b3b80d8
[Hexagon] Adding combine reg-reg forms.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223485 91177308-0d34-0410-b5e6-96231b3b80d8
Refactor duplicated code. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223486 91177308-0d34-0410-b5e6-96231b3b80d8
[Hexagon] [NFC] Rearranging def order.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223487 91177308-0d34-0410-b5e6-96231b3b80d8
[Hexagon] [NFC] Rearranging patterns and mux instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223488 91177308-0d34-0410-b5e6-96231b3b80d8