RegisterId can represent a physical register, a MCRegUnit, or
an index into a side structure that stores register masks. These 3
types were encoded by using the physical reg, stack slot, and
virtual register encoding partitions from the Register class.
This encoding scheme alias wasn't well contained so
Register::index2StackSlot and Register::stackSlotIndex appeared
in multiple places.
This patch gives RegisterRef its own encoding defines and separates
it from Register.
I've removed the generic idx() method in favor of getAsMCReg(),
getAsMCRegUnit(), and getMaskIdx() for some degree of type safety.
Some places used the RegisterId field of RegisterRef directly as a
register. Those have been updated to use getAsMCReg.
Some special cases for RegisterId 0 have been removed as it can
be treated like a MCRegister by existing code.
I think I want to rename the Reg field of RegisterRef to Id, but
I'll do that in another patch.
Additionally, callers of the RegisterRef constructor need to be
audited for implicit conversions from Register/MCRegister
to unsigned.
DenseSet, SmallPtrSet, SmallSet, SetVector, and StringSet recently
gained C++23-style insert_range. This patch replaces:
Dest.insert(Src.begin(), Src.end());
with:
Dest.insert_range(Src);
This patch does not touch custom begin like succ_begin for now.
When a def in a block A reaches another block B that is in A's iterated
dominance frontier, a phi node is added to B for the def register.
A clobbering def can be created at a call instruction, for a register
clobbered by a call.
However, phi nodes are not created for a register, when one of the
reaching defs of the register is a clobbering def.
This patch adds phi nodes for registers that have a clobbering reaching
def. These additional phis help in checking reaching defs for an
instruction in RDF based copy propagation and addressing mode
optimizations.
During RDF graph construction, linkRefUp method links a register ref to
its upward reaching defs until all RegUnits of the ref have been covered
by defs.
However, when a sub-register def covers some, but not all, of the
RegUnits of a previous super-register def, a super-register ref is not
linked to the super-register def.
This can result in certain super register defs being dead code
eliminated.
This patch fixes the cover check for a register ref. A def must be
skipped only when all RegUnits of that def have already been covered by
a previously seen def.
- Add option to ignore reserved registers
- Add possibility to track selected registers or register classes only
Tracking is done based on register units, so the set of registers to track
is translated into a set of register units.
Recommit with the fix for incorrect `constexpr` with `hash` from a later
commit, and a fix for "std::swap(std::less<RegisterRef>...)" issue with
MSVC's `std::map`.
This reverts commit 859b05b02d3fd9ab6b77f2bed8df6902fe704806.
Also reverts these follow-ups:
Revert "[RDF] Remove `constexpr` from `hash"
This reverts commit 621507ce20ad8eef2986be2712631165e53b7d91.
Revert "[RDF] Do not use trailing return type after all, NFC"
This reverts commit 46e19e3a2c45e7fb5f501bdb983a7151c158304f.
Revert "[RDF] Stop looking when reached code node in getNextRef with NextOnly"
This reverts commit a049ce9d1bd5a7c1c4fcccc6a801b72b00ea8e0f.
Revert "[RDF] Use trailing return type syntax, NFC"
This reverts commit d3b34b7f3a7cbfc96aea897419f167b5ee19e61a.
Revert "[RDF] Define short type names: NodeAddr<XyzNode*> -> Xyz, NFC"
This reverts commit f8ed60b56d1948422dda924fcf450560591e8a19.
The name rdf::Use conflicts with llvm::Use when both namespaces are
used via `using namespace`. Specifically this happened in the declaration
of DataFlowGraph::newUse (in RDFGraph.cpp):
```
using namespace rdf;
Use newUse(...); <-- Lookup conflict for "Use"
```
Since the TRT lookup starts in a different namespace than that of the
leading type, this serves as a workaround. In general the rdf namespace
will not likely be introduced via `using namespace`, so this shouldn't
be a problem elsewhere.
This isn't quite using register units, but it's getting close. The phi
generation is driven by register units, but each phi still contains a
reference to a register, potentially with a mask that amounts to a unit.
In cases of explicit register aliasing this may still create phis with
references that are aliased, whereas separate phis would ideally contain
disjoint references (this is all within a single basic block).
Previously phis used maximal registers, now they use minimal. This is a
step towards both, using register units directly, and a simpler liveness
calculation algorithm. The idea is that a phi cannot reach a reference
to anything smaller than the phi itself represents. Before there could
be a phi for R1_R0, now there will be two for this case (assuming R0 and
R1 have one unit each).
The new methods return a range for easier iteration. Use them everywhere
instead of getImplicitUses, getNumImplicitUses, getImplicitDefs and
getNumImplicitDefs. A future patch will remove the old methods.
In some use cases the new methods are less efficient because they always
have to scan the whole uses/defs array to count its length, but that
will be fixed in a future patch by storing the number of implicit
uses/defs explicitly in MCInstrDesc. At that point there will be no need
to 0-terminate the arrays.
Differential Revision: https://reviews.llvm.org/D142215
The build breakages should be addressed by d4abdd2e3d:
[CMake] Check CMAKE_CXX_STANDARD and error if it's to old
Thanks to Tobias and Roy for addressing these issues.
This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https://reviews.llvm.org/D121169
RDF is designed to be target agnostic. Therefore it would be useful to have it available for other targets, such as X86.
Based on a previous patch by Krzysztof Parzyszek
Differential Revision: https://reviews.llvm.org/D75932
