The previous implementation was extending the live range of SGPRs
by modifying the live intervals directly. This was causing a lot
of machine verification errors when the machine scheduler was enabled.
The new implementation adds pseudo instructions with implicit uses to
extend the live ranges of SGPRs, which works much better.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218351 91177308-0d34-0410-b5e6-96231b3b80d8
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.
Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214838 91177308-0d34-0410-b5e6-96231b3b80d8
SGPRs are written by instructions that sometimes will ignore control flow,
which means if you have code like:
if (VGPR0) {
SGPR0 = S_MOV_B32 0
} else {
SGPR0 = S_MOV_B32 1
}
The value of SGPR0 will 1 no matter what the condition is.
In order to deal with this situation correctly, we need to view the
program as if it were a single basic block when we calculate the
live ranges for the SGPRs. They way we actually update the live
range is by iterating over all of the segments in each LiveRange
object and setting the end of each segment equal to the start of
the next segment. So a live range like:
[3888r,9312r:0)[10032B,10384B:0) 0@3888r
will become:
[3888r,10032B:0)[10032B,10384B:0) 0@3888r
This change will allow us to use SALU instructions within branches.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212215 91177308-0d34-0410-b5e6-96231b3b80d8
