This patch introduces a new instruction stage named 'IS_PENDING'.
An instruction transitions from the IS_DISPATCHED to the IS_PENDING stage if
input registers are not available, but their latency is known.
This patch also adds a new set of instructions named 'PendingSet' to class
Scheduler. The idea is that the PendingSet will only contain instructions that
have reached the IS_PENDING stage.
By construction, an instruction in the PendingSet is only dependent on
instructions that have already reached the execution stage. The plan is to use
this knowledge to identify bottlenecks caused by data dependencies (see
PR37494).
Differential Revision: https://reviews.llvm.org/D58066
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DispatchStage should always delegate to an object of class RegisterFile the task
of updating data dependencies. ReadState and WriteState objects should not be
modified directly by DispatchStage.
This patch also renames stage IS_AVAILABLE to IS_DISPATCHED.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353170 91177308-0d34-0410-b5e6-96231b3b80d8
In some cases, it is faster to just grow the set of 'Users' rather than
performing a llvm::find_if every time a new user is added to
the set. No functional change intended.
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to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
