Memory legalizer, waitcnt, and shrink passes can perturb the instructions,
which means that the post-RA hazard recognizer pass should run after them.
Otherwise, one of those passes may invalidate the work done by the hazard
recognizer. Note that this has adverse side-effect that any consecutive
S_NOP 0's, emitted by the hazard recognizer, will not be shrunk into a
single S_NOP <N>. This should be addressed in a follow-on patch.
Differential Revision: https://reviews.llvm.org/D49288
llvm-svn: 337154
Memory clauses are formed into bundles in presence of xnack.
Their source operands are marked as early-clobber.
This allows to allocate distinct source and destination registers
within a clause and prevent breaking the clause with s_nop in the
hazard recognizer.
Clauses are undone before post-RA scheduler to allow some rescheduling,
which will not break the clause since artificial edges are created in
the dag to keep memory operations together. Yet this allows a better
ILP in some cases.
Differential Revision: https://reviews.llvm.org/D47511
llvm-svn: 333691
Mark Searles