This effectively disables the 'turbo' functionality of the greedy register
allocator where all new live ranges created by splitting would be reconsidered
as if they were originals.
There are two reasons for doing this, 1. It guarantees that the algorithm
terminates. Early versions were prone to infinite looping in certain corner
cases. 2. It is a 2x speedup. We can skip a lot of unnecessary interference
checks that won't lead to good splitting anyway.
The problem is that region splitting only gets one shot, so it should probably
be changed to target multiple physical registers at once.
Local live range splitting is still 'turbo' enabled. It only accounts for a
small fraction of compile time, so it is probably not necessary to do anything
about that.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126781 91177308-0d34-0410-b5e6-96231b3b80d8
1. Inform users of ADDEs with two 0 operands that it never sets carry
2. Fold other ADDs or ADDCs into the ADDE if possible
It would be neat if we could do the same thing for SETCC+ADD eventually, but we can't do that in target independent code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126557 91177308-0d34-0410-b5e6-96231b3b80d8
is possible to do better if the high bit is set in either KnownZero/KnownOne, but
in practice NumSignBits is always 1 when we are zero extending because nothing
is known about that register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126465 91177308-0d34-0410-b5e6-96231b3b80d8
New live ranges are assigned in long -> short order, but live ranges that have
been evicted at least once are deferred and assigned in short -> long order.
Also disable splitting and spilling for live ranges seen for the first time.
The intention is to create a realistic interference pattern from the heavy live
ranges before starting splitting and spilling around it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126451 91177308-0d34-0410-b5e6-96231b3b80d8
Limit the folding of any_ext and sext into the load operation to scalars.
Limit the active-bits trunc optimization to scalars.
Document vector trunc and vector sext in LangRef.
Similar to commit 126080 (for enabling zext).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126424 91177308-0d34-0410-b5e6-96231b3b80d8
The problem was codegen guessing the wrong values and printing
.section .eh_frame,"aMS",@progbits,4
It is not clear at all if Codegen should try to guess, MC is the
one that should know the default flags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126421 91177308-0d34-0410-b5e6-96231b3b80d8
registers at phis. This enables us to eliminate a lot of pointless zexts during
the DAGCombine phase. This fixes <rdar://problem/8760114>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126380 91177308-0d34-0410-b5e6-96231b3b80d8
When a large live range is evicted, it will usually be split when it comes
around again. By deferring evicted live ranges, the splitting happens at a time
when the interference pattern is more realistic. This prevents repeated
splitting and evictions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126282 91177308-0d34-0410-b5e6-96231b3b80d8
Use interval sizes instead of spill weights to determine if it is legal to evict
interference. A smaller interval can evict interference if all interfering live
ranges are larger.
Allow multiple interferences to be evicted as along as they are all larger than
the live range being allocated.
Spill weights are still used to select the preferred eviction candidate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126276 91177308-0d34-0410-b5e6-96231b3b80d8
This is based on the observation that long live ranges are more difficult to
allocate, so there is a better chance of solving the puzzle by handling the big
pieces first. The allocator will evict and split long alive ranges when they get
in the way.
RABasic is still using spill weights for its priority queue, so the interface to
the queue has been virtualized.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126259 91177308-0d34-0410-b5e6-96231b3b80d8
share entries. Add a DenseSet to MachineConstantPool for the MachineCPVs that
it owns.
This will hopefully fix the MC/ARM/elf-reloc-01.ll failure on the leaks bots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126218 91177308-0d34-0410-b5e6-96231b3b80d8
at phis. This enables us to eliminate a lot of pointless zexts during the DAGCombine
phase. This fixes <rdar://problem/8760114>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126170 91177308-0d34-0410-b5e6-96231b3b80d8
In other words, do not keep track of argument's location. The debugger (gdb) is not prepared to see line table entries for arguments. For the debugger, "second" line table entry marks beginning of function body.
This requires some coordination with debugger to get this working.
- The debugger needs to be aware of prolog_end attribute attached with line table entries.
- The compiler needs to accurately mark prolog_end in line table entries (at -O0 and at -O1+)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126155 91177308-0d34-0410-b5e6-96231b3b80d8
An original endpoint is an instruction that killed or defined the original live
range before any live ranges were split.
When splitting global live ranges, avoid creating local live ranges without any
original endpoints. We may still create global live ranges without original
endpoints, but such a range won't be split again, and live range splitting still
terminates.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126151 91177308-0d34-0410-b5e6-96231b3b80d8
