[DAGCombiner] Add add/sub saturation undef handling
authorSimon Pilgrim <llvm-dev@redking.me.uk>
Mon, 14 Jan 2019 14:16:24 +0000 (14:16 +0000)
committerSimon Pilgrim <llvm-dev@redking.me.uk>
Mon, 14 Jan 2019 14:16:24 +0000 (14:16 +0000)
commit7fc6882374f805ed780f07001e317c8b0dc7711a
tree1e4d79d8bc29594a5796263f5808eaa8d65c3806
parent7a99727c62ac457ad122aa6ede3500b75184426c
[DAGCombiner] Add add/sub saturation undef handling

Match ConstantFolding.cpp:
(add_sat x, undef) -> -1
(sub_sat x, undef) -> 0

llvm-svn: 351070
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/test/CodeGen/X86/combine-add-ssat.ll
llvm/test/CodeGen/X86/combine-add-usat.ll
llvm/test/CodeGen/X86/combine-sub-ssat.ll
llvm/test/CodeGen/X86/combine-sub-usat.ll