R600/SI: Add instruction shrinking pass

This pass converts 64-bit instructions to 32-bit when possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213561 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges."

This reverts commit r213474 (and r213475), which causes a miscompile on
a stage2 LTO build.  I'll reply on the list in a moment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213562 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Initialize unused VOP3 sources to 0 instead of SIOperand.ZERO

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213563 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Initailize encoding fields of unused VOP3 modifiers to 0

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213564 91177308-0d34-0410-b5e6-96231b3b80d8
Replace the result usages while legalizing cmpxchg.

We should update the usages to all of the results;
otherwise, we might get assertion failure or SEGV during
the type legalization of ATOMIC_CMP_SWAP_WITH_SUCCESS
with two or more illegal types.

For example, in the following sequence, both i8 and i1
might be illegal in some target, e.g. armv5, mipsel, mips64el,

    %0 = cmpxchg i8* %ptr, i8 %desire, i8 %new monotonic monotonic
    %1 = extractvalue { i8, i1 } %0, 1

Since both i8 and i1 should be legalized, the corresponding
ATOMIC_CMP_SWAP_WITH_SUCCESS dag will be checked/replaced/updated
twice.

If we don't update the usage to *ALL* of the results in the
first round, the DAG for extractvalue might be processed earlier.
The GetPromotedInteger() will result in assertion failure,
because its operand (i.e. the success bit of cmpxchg) is not
promoted beforehand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213569 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Separate encoding and operand definitions into their own classes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213570 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Refactor VOP3 instruction definitions

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213571 91177308-0d34-0410-b5e6-96231b3b80d8