This fixes PR10463. A two-address instruction with an <undef> use
operand was incorrectly rewritten so the def and use no longer used the
same register, violating the tie constraint.
Fix this by always rewriting <undef> operands with the register a def
operand would use.
llvm-svn: 135885
This method computes the edge bundles that should be live when splitting
around a compact region. This is independent of interference.
The function returns false if the live range was already a compact
region, or the compact region doesn't have any live bundles - it would
be the same as splitting around basic blocks.
Compact regions are computed using the normal spill placement code. We
pretend there is interference in all live-through blocks that don't use
the live range. This removes all edges from the Hopfield network used
for spill placement, so it converges instantly.
llvm-svn: 135847
If there is no interference and no last split point, we cannot
enterIntvBefore(Stop) - that function needs a real instruction.
Use enterIntvAtEnd instead for that very easy case.
This code doesn't currently run, it is needed by multi-way splitting.
llvm-svn: 135846
A split candidate can have a null PhysReg which means that it doesn't
map to a real interference pattern. Instead, pretend that all through
blocks have interference.
This makes it possible to generate compact regions where the live range
doesn't go through blocks that don't use it. The live range will still
be live between directly connected blocks with uses.
Splitting around a compact region tends to produce a live range with a
high spill weight, so it may evict a less dense live range.
llvm-svn: 135845
This method matches addLinks - All the listed blocks are considered to
have interference, so they add a negative bias to their bundles.
This could also be done by addConstraints, but that requires building a
separate BlockConstraint array.
llvm-svn: 135844
This makes TargetRegisterClass slightly slower. Next step will be making contains faster.
Eventually TargetRegisterClass will be killed entirely.
llvm-svn: 135835
The immediate is in the range 1-32, but is encoded as 0-31 in a 5-bit bitfield.
Update the representation such that we store the operand as 0-31, allowing us
to remove the encoder method and the special case handling in the disassembler.
Update the assembly parser and the instruction printer accordingly.
llvm-svn: 135823
