This patch includes the following updates to the load/store refactoring effort introduced in D93370:
- Update various VSX patterns that use to "force" an XForm, to instead just XForm.
This allows the ability for the patterns to compute the most optimal addressing
mode (and to produce a DForm instruction when possible)
- Update pattern and test case for the LXVD2X/STXVD2X intrinsics
- Update LIT test cases that use to use the XForm instruction to use the DForm instruction
Differential Revision: https://reviews.llvm.org/D95115
A shift and add/sub sequence combination is faster in place of a multiply by constant.
Because the cycle or latency of multiply is not huge, we only consider such following
worthy patterns.
```
(mul x, 2^N + 1) => (add (shl x, N), x)
(mul x, -(2^N + 1)) => -(add (shl x, N), x)
(mul x, 2^N - 1) => (sub (shl x, N), x)
(mul x, -(2^N - 1)) => (sub x, (shl x, N))
```
And the cycles or latency is subtarget-dependent so that we need consider the
subtarget to determine to do or not do such transformation.
Also data type is considered for different cycles or latency to do multiply.
Differential Revision: https://reviews.llvm.org/D58950
llvm-svn: 357233
Amy Kwan