Instead of inserting everything after the 'root' of the reduction,
insert all instructions as close to their operands as possible. This
can help reduce register pressure.

Differential Revision: https://reviews.llvm.org/D67392

llvm-svn: 374981

    
The incoming accumulator value can be discovered through a sext, in
which case there will be a mismatch between the input and the result.
So sign extend the accumulator input if we're performing a 64-bit mac.

Differential Revision: https://reviews.llvm.org/D67220

llvm-svn: 371370

For any unpaired muls, we accumulate them as an input to the
reduction. Check the type of the mul and perform a sext if the
existing accumlator input type is not the same.

Differential Revision: https://reviews.llvm.org/D66993

llvm-svn: 370851

rL369567 reverted a couple of recent changes made to ARMParallelDSP
because of a miscompilation error: PR43073.

The issue stemmed from an underlying bug that was caused by adding
muls into a reduction before it was proved that they could be executed
in parallel with another mul.

Most of the changes here are from the previously reverted commits.
The additional changes have been made area:
1) The Search function now doesn't insert any muls into the Reduction
   object. That now happens once the search has successfully finished.
2) For any muls added into the reduction but that weren't paired, we
   accumulate their values as an input into the smlad.

Differential Revision: https://reviews.llvm.org/D66660

llvm-svn: 370171

llvm-svn: 369567

As loads are combined and widened, we replaced their sext users
operands whereas we should have been replacing the uses of the sext.
I've added a load of tests, with only a few of them originally
causing assertion failures, the rest improve pattern coverage.

Differential Revision: https://reviews.llvm.org/D65740

llvm-svn: 368404

Run across a whole function, visiting each basic block one at a time.

Differential Revision: https://reviews.llvm.org/D65324

llvm-svn: 367389