Dead phi nodes are needed for code motion (such as copy propagation),
where a new use would be placed in a location that would be dominated
by a dead phi. Such a transformation is not legal for copy propagation,
and the existence of the phi would prevent it, but if the phi is not
there, it may appear to be valid.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267932 91177308-0d34-0410-b5e6-96231b3b80d8
Change TargetInstrInfo API to take `MachineInstr&` instead of
`MachineInstr*` in the functions related to predicated instructions
(I'll try to come back later and get some of the rest). All of these
functions require non-null parameters already, so references are more
clear. As a bonus, this happens to factor away a host of implicit
iterator => pointer conversions.
No functionality change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261605 91177308-0d34-0410-b5e6-96231b3b80d8
Target independent, SSA-based data flow framework for representing
data flow between physical registers.
This commit implements the creation of the actual data flow graph.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257477 91177308-0d34-0410-b5e6-96231b3b80d8
Benjamin Kramer