The loop-carried dependency detection logic in isLoopCarriedDep relies
on the load and store using the same definition for the base register.
This misses the case of post-increment loads and stores whose base
register are different PHI initialized from the same initial value.
This commit extends the logic to accept the load and store having
different PHI base address provided that they had the same initial value
when entering the loop and are incremented by the same amount in each
loop.
Reviewed By: bcahoon
Differential Revision: https://reviews.llvm.org/D136463
The method of counting resource consumption is modified to be based on
"Cycles" value when DFA is not used.
The calculation of ResMII is modified to total "Cycles" and divide it
by the number of units for each resource. Previously, ResMII was
excessive because it was assumed that resources were consumed for
the cycles of "Latency" value.
The method of resource reservation is modified similarly. When a
value of "Cycles" is larger than 1, the resource is considered to be
consumed by 1 for cycles of its length from the scheduled cycle.
To realize this, ResourceManager maintains a resource table for all
slots. Previously, resource consumption was always 1 for 1 cycle
regardless of the value of "Cycles" or "Latency".
In addition, the number of micro operations per cycle is modified to
be constrained by "IssueWidth". To disable the constraint,
--pipeliner-force-issue-width=100 can be used.
For the case of using DFA, the scheduling results are unchanged.
Reviewed By: dpenry
Differential Revision: https://reviews.llvm.org/D133572
This interface allows a target to reject a proposed
SMS schedule. For Hexagon/PowerPC, all schedules
are accepted, leaving behavior unchanged. For ARM,
schedules which exceed register pressure limits are
rejected.
Also, two RegisterPressureTracker methods now need to be public so
that register pressure can be computed by more callers.
Reapplication of D128941/(reversion:D132037) with small fix.
Differential Revision: https://reviews.llvm.org/D132170
This reverts commit 8c4aea438c.
Needed because buildbot failures (warnings) gave a clue that there was
a functional bug in the ARM rejection logic.
Reviewed By: dmgreen
Differential Revision: https://reviews.llvm.org/D132037
This interface allows a target to reject a proposed
SMS schedule. For Hexagon/PowerPC, all schedules
are accepted, leaving behavior unchanged. For ARM,
schedules which exceed register pressure limits are
rejected.
Also, two RegisterPressureTracker methods now need to be public so
that register pressure can be computed by more callers.
Reviewed By: dmgreen
Differential Revision: https://reviews.llvm.org/D128941
This was stored in LiveIntervals, but not actually used for anything
related to LiveIntervals. It was only used in one check for if a load
instruction is rematerializable. I also don't think this was entirely
correct, since it was implicitly assuming constant loads are also
dereferenceable.
Remove this and rely only on the invariant+dereferenceable flags in
the memory operand. Set the flag based on the AA query upfront. This
should have the same net benefit, but has the possible disadvantage of
making this AA query nonlazy.
Preserve the behavior of assuming pointsToConstantMemory implying
dereferenceable for now, but maybe this should be changed.
Prior to ordering instructions to be scheduled, the machine pipeliner
update recurrence node sets in groupRemainingNodes() by adding in a
given node set any node on the dependency path from a node set with
higher priority to the given node set. The function computePath() that
determine what constitutes a path follows artificial dependencies.
However, when ordering the nodes in the resulting node sets,
computeNodeOrder() calls ignoreDependence when looking at dependencies
which ignores artificial dependencies. This can cause a node not to be
scheduled which then causes wrong code generation and in the case of a
debug build will lead to an assert failure in generatePhis() in
ModuloScheduler.cpp.
This commit adds calls to ignoreDependence() in computePath() to not add
any node in groupRemainingNodes() that would not be ordered by
computeNodeOrder().
Reviewed By: sgundapa
Differential Revision: https://reviews.llvm.org/D124267
Fixed "private field is not used" warning when compiled
with clang.
original commit: 28d09bbbc3
reverted in: fa49021c68
------
This patch permits Swing Modulo Scheduling for ARM targets
turns it on by default for the Cortex-M7. The t2Bcc
instruction is recognized as a loop-ending branch.
MachinePipeliner is extended by adding support for
"unpipelineable" instructions. These instructions are
those which contribute to the loop exit test; in the SMS
papers they are removed before creating the dependence graph
and then inserted into the final schedule of the kernel and
prologues. Support for these instructions was not previously
necessary because current targets supporting SMS have only
supported it for hardware loop branches, which have no
loop-exit-contributing instructions in the loop body.
The current structure of the MachinePipeliner makes it difficult
to remove/exclude these instructions from the dependence graph.
Therefore, this patch leaves them in the graph, but adds a
"normalization" method which moves them in the schedule to
stage 0, which causes them to appear properly in kernel and
prologues.
It was also necessary to be more careful about boundary nodes
when iterating across successors in the dependence graph because
the loop exit branch is now a non-artificial successor to
instructions in the graph. In additional, schedules with physical
use/def pairs in the same cycle should be treated as creating an
invalid schedule because the scheduling logic doesn't respect
physical register dependence once scheduled to the same cycle.
Reviewed By: dmgreen
Differential Revision: https://reviews.llvm.org/D122672
This patch permits Swing Modulo Scheduling for ARM targets
turns it on by default for the Cortex-M7. The t2Bcc
instruction is recognized as a loop-ending branch.
MachinePipeliner is extended by adding support for
"unpipelineable" instructions. These instructions are
those which contribute to the loop exit test; in the SMS
papers they are removed before creating the dependence graph
and then inserted into the final schedule of the kernel and
prologues. Support for these instructions was not previously
necessary because current targets supporting SMS have only
supported it for hardware loop branches, which have no
loop-exit-contributing instructions in the loop body.
The current structure of the MachinePipeliner makes it difficult
to remove/exclude these instructions from the dependence graph.
Therefore, this patch leaves them in the graph, but adds a
"normalization" method which moves them in the schedule to
stage 0, which causes them to appear properly in kernel and
prologues.
It was also necessary to be more careful about boundary nodes
when iterating across successors in the dependence graph because
the loop exit branch is now a non-artificial successor to
instructions in the graph. In additional, schedules with physical
use/def pairs in the same cycle should be treated as creating an
invalid schedule because the scheduling logic doesn't respect
physical register dependence once scheduled to the same cycle.
Reviewed By: dmgreen
Differential Revision: https://reviews.llvm.org/D122672
AttributeList::hasAttribute() is confusing, use clearer methods like
hasParamAttr()/hasRetAttr().
Add hasRetAttr() since it was missing from AttributeList.
Main reason is preparation to transform AliasResult to class that contains
offset for PartialAlias case.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D98027
Interval value
The II value was incremented before exiting the loop, and therefor when
used in the optimization remarks and debug dumps it did not reflect the
initiation interval actually used in Schedule.
Differential Revision: https://reviews.llvm.org/D95692
1. Removed #include "...AliasAnalysis.h" in other headers and modules.
2. Cleaned up includes in AliasAnalysis.h.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D92489
Currently, we have some confusion in the codebase regarding the
meaning of LocationSize::unknown(): Some parts (including most of
BasicAA) assume that LocationSize::unknown() only allows accesses
after the base pointer. Some parts (various callers of AA) assume
that LocationSize::unknown() allows accesses both before and after
the base pointer (but within the underlying object).
This patch splits up LocationSize::unknown() into
LocationSize::afterPointer() and LocationSize::beforeOrAfterPointer()
to make this completely unambiguous. I tried my best to determine
which one is appropriate for all the existing uses.
The test changes in cs-cs.ll in particular illustrate a previously
clearly incorrect AA result: We were effectively assuming that
argmemonly functions were only allowed to access their arguments
after the passed pointer, but not before it. I'm pretty sure that
this was not intentional, and it's certainly not specified by
LangRef that way.
Differential Revision: https://reviews.llvm.org/D91649
This patch adds ORE for MachinePipeliner, so that people can anaylyze
their code using opt-viewer or other tools, then optimize the code to
catch more piplining opportunities.
Reviewed By: bcahoon
Differential Revision: https://reviews.llvm.org/D79368
This allows targets to know exactly which operands are contributing to
the dependency, which is required for targets with per-operand
scheduling models.
Differential Revision: https://reviews.llvm.org/D77135
The current implementation collects all Preds/Succs of a Dep of kind Output, creating a long chain and subsequently a schedule with an unnecessarily large II.
Was this done on purpose for a reason I'm missing?
Reviewed By: bcahoon
Differential Revision: https://reviews.llvm.org/D75424
Thomas Preud'homme