Re-enable commit r323991 now that r325931 has been committed to make
MachineOperand::isRenamable() check more conservative w.r.t. code
changes and opt-in on a per-target basis.
llvm-svn: 326208
This reverts commit r323991.
This commit breaks target that don't model all the register constraints
in TableGen. So far the workaround was to set the
hasExtraXXXRegAllocReq, but it proves that it doesn't cover all the
cases.
For instance, when mutating an instruction (like in the lowering of
COPYs) the isRenamable flag is not properly updated. The same problem
will happen when attaching machine operand from one instruction to
another.
Geoff Berry is working on a fix in https://reviews.llvm.org/D43042.
llvm-svn: 325421
Summary:
This change extends MachineCopyPropagation to do COPY source forwarding
and adds an additional run of the pass to the default pass pipeline just
after register allocation.
This version of this patch uses the newly added
MachineOperand::isRenamable bit to avoid forwarding registers is such a
way as to violate constraints that aren't captured in the
Machine IR (e.g. ABI or ISA constraints).
This change is a continuation of the work started in D30751.
Reviewers: qcolombet, javed.absar, MatzeB, jonpa, tstellar
Subscribers: tpr, mgorny, mcrosier, nhaehnle, nemanjai, jyknight, hfinkel, arsenm, inouehrs, eraman, sdardis, guyblank, fedor.sergeev, aheejin, dschuff, jfb, myatsina, llvm-commits
Differential Revision: https://reviews.llvm.org/D41835
llvm-svn: 323991
In Thumb 1, with the new ADDCARRY / SUBCARRY the scheduler may need to do
copies CPSR ↔ GPR but not all Thumb1 targets implement them.
The schedule can attempt, before attempting a copy, to clone the instructions
but it does not currently do that for nodes with input glue. In this patch we
introduce a target-hook to let the hook decide if a glued machinenode is still
eligible for copying. In this case these are ARM::tADCS and ARM::tSBCS .
As a follow-up of this change we should actually implement the copies for the
Thumb1 targets that do implement them and restrict the hook to the targets that
can't really do such copy as these clones are not ideal.
This change fixes PR35836.
Differential Revision: https://reviews.llvm.org/D42051
llvm-svn: 323857
Geoff Berry