[SelectionDAG] swap select_cc operands to enable folding
The DAGCombiner tries to SimplifySelectCC as follows:
select_cc(x, y, 16, 0, cc) -> shl(zext(set_cc(x, y, cc)), 4)
It can't cope with the situation of reordered operands:
select_cc(x, y, 0, 16, cc)
In that case we just need to swap the operands and invert the Condition Code:
select_cc(x, y, 16, 0, ~cc)
Differential Revision: https://reviews.llvm.org/D53236
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346484 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed