12 bit is not enough for PPC's target specific flags. If 8 bit for the
bitmask flags, 4 bit for the direct mask, PPC can total have 16 direct
mask and 8 bitmask. Not enough for PPC, see this issue in
https://github.com/llvm/llvm-project/pull/66316
Redesign how PPC target set the target specific flags. With this patch,
all ppc target flags are direct flags. No bitmask flag in PPC anymore.
This patch aligns with some targets like X86 which also has many target
specific flags.
The patch also fixes a bug related to flag `MO_TLSGDM_FLAG` and `MO_LO`.
They are the same value and the test case changes in this PR shows the
bug.
These are picked up from getMemOperandsWithOffsetWidth but weren't then
being passed through to shouldClusterMemOps, which forces backends to
collect the information again if they want to use the kind of heuristics
typically used for the similar shouldScheduleLoadsNear function (e.g.
checking the offset is within 1 cache line).
This patch just adds the parameters, but doesn't attempt to use them.
There is potential to use them in the current PPC and AArch64
shouldClusterMemOps implementation, and I intend to use the offset in
the heuristic for RISC-V. I've left these for future patches in the
interest of being as incremental as possible.
As noted in the review and in an inline FIXME, an ElementCount-style abstraction may later be used to condense these two parameters to one argument. ElementCount isn't quite suitable as it doesn't support negative offsets.
getOperandLatency has the following behavior: it returns -1 as a special
value, negative numbers other than -1 on some target-specific overrides,
or a valid non-negative latency. This behavior can be surprising, as
some callers do arithmetic on these negative values. Change the
interface of getOperandLatency to return a std::optional<unsigned> to
prevent surprises in callers. While at it, change the interface of
getInstrLatency to return unsigned instead of int.
This change was inspired by a refactoring in
TargetSchedModel::computeOperandLatency.
Don't blindly copy the original flags from the pre-reassociated
instrutions.
This copied the integer poison flags which are not safe to preserve
after reassociation.
For the FP flags, I think we should only keep the intersection of
the flags. Override setSpecialOperandAttr to do this.
Fixes#72777.
The MI Peephole pass has grown to include a large number of transformations over the years. Many of the transformations require re-computation of kill flags but don't do a good job of re-computing them. This causes us to have very common failures when the compiler is built with expensive checks. Over time, we added and augmented a function that is supposed to go and fix up kill flags after each transformation but we keep missing cases.
This patch does the following:
- Removes the function to re-compute kill flags
- Adds LiveVariables to compute and maintain kill flags while transforming code
- Adds re-computation of kill flags for the post-RA peepholes for each block that contains a transformed instruction
Reviewed By: stefanp
Differential Revision: https://reviews.llvm.org/D133103
This will make it easy for callers to see issues with and fix up calls
to createTargetMachine after a future change to the params of
TargetMachine.
This matches other nearby enums.
For downstream users, this should be a fairly straightforward
replacement,
e.g. s/CodeGenOpt::Aggressive/CodeGenOptLevel::Aggressive
or s/CGFT_/CodeGenFileType::
See issue #64166 for more information about the layering issue.
The PPCMCTargetDesc library was including CodeGen headers such as
PPCInstrInfo.h and calling inline functions in them. This doesn't work
in the Bazel build, and is error-prone. If the inline function moves to
a cpp file, it will result in linker errors.
To address the issue, I moved several inline functions to
PPCMCTargetDesc.cpp, and declared them in the PPC namespace in
PPCMCTargetDesc.h, which seemed like the most straightforward fix.
Differential Revision: https://reviews.llvm.org/D156488
getOperandConstraint does not return a bool, it returns an int. It
returns -1 if there is no TIED_TO.
Additionally, TIED_TO is only set on use operands not defs and it
points to the def that the use is tied to. So calling it on operand 0
is guaranteed to return -1.
As far as I can tell this code must have been copied from the
generic implementation prior to 6aa2744bed0b8.o
Unfortunately, this code is not executed in lit tests. I just happened
to notice it while looking for other uses of TIED_TO for something
I was working on.
Reviewed By: nemanjai
Differential Revision: https://reviews.llvm.org/D152754
Currently `isTriviallyReMaterializable` calls
`isReallyTriviallyReMaterializable` and
`isReallyTriviallyReMaterializableGeneric`. The two interfaces
are confusing, but there are also some real issues with this.
The documentation of this function (see below) suggests that
`isReallyTriviallyRematerializable` allows the target to override the
default behaviour.
/// For instructions with opcodes for which the M_REMATERIALIZABLE flag is
/// set, this hook lets the target specify whether the instruction is actually
/// trivially rematerializable, taking into consideration its operands.
It however implements something different. The default behaviour
is the analysis done in `isReallyTriviallyReMaterializableGeneric`,
which is testing if it is safe to rematerialize the MachineInstr.
The result of `isReallyTriviallyReMaterializable` is only considered if
`isReallyTriviallyReMaterializableGeneric` returns `false`. That means
there is no way to override the default behaviour if
`isReallyTriviallyReMaterializableGeneric` returns true (i.e. it is safe to
rematerialize, but we'd rather not).
By making this a single interface, we can override the interface to do either.
Reviewed By: craig.topper, nemanjai
Differential Revision: https://reviews.llvm.org/D156520
Sometimes an developer would like to have more control over cmov vs branch. We have unpredictable metadata in LLVM IR, but currently it is ignored by X86 backend. Propagate this metadata and avoid cmov->branch conversion in X86CmovConversion for cmov with this metadata.
Example:
```
int MaxIndex(int n, int *a) {
int t = 0;
for (int i = 1; i < n; i++) {
// cmov is converted to branch by X86CmovConversion
if (a[i] > a[t]) t = i;
}
return t;
}
int MaxIndex2(int n, int *a) {
int t = 0;
for (int i = 1; i < n; i++) {
// cmov is preserved
if (__builtin_unpredictable(a[i] > a[t])) t = i;
}
return t;
}
```
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D118118
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
Change MCInstrDesc::operands to return an ArrayRef so we can easily use
it everywhere instead of the (IMHO ugly) opInfo_begin and opInfo_end.
A future patch will remove opInfo_begin and opInfo_end.
Also use it instead of raw access to the OpInfo pointer. A future patch
will remove this pointer.
Differential Revision: https://reviews.llvm.org/D142213
Use deduction guides instead of helper functions.
The only non-automatic changes have been:
1. ArrayRef(some_uint8_pointer, 0) needs to be changed into ArrayRef(some_uint8_pointer, (size_t)0) to avoid an ambiguous call with ArrayRef((uint8_t*), (uint8_t*))
2. CVSymbol sym(makeArrayRef(symStorage)); needed to be rewritten as CVSymbol sym{ArrayRef(symStorage)}; otherwise the compiler is confused and thinks we have a (bad) function prototype. There was a few similar situation across the codebase.
3. ADL doesn't seem to work the same for deduction-guides and functions, so at some point the llvm namespace must be explicitly stated.
4. The "reference mode" of makeArrayRef(ArrayRef<T> &) that acts as no-op is not supported (a constructor cannot achieve that).
Per reviewers' comment, some useless makeArrayRef have been removed in the process.
This is a follow-up to https://reviews.llvm.org/D140896 that introduced
the deduction guides.
Differential Revision: https://reviews.llvm.org/D140955
With D134950, targets get notified when a virtual register is created and/or
cloned. Targets can do the needful with the delegate callback. AMDGPU propagates
the virtual register flags maintained in the target file itself. They are useful
to identify a certain type of machine operands while inserting spill stores and
reloads. Since RegAllocFast spills the physical register itself, there is no way
its virtual register can be mapped back to retrieve the flags. It can be solved
by passing the virtual register as an additional argument. This argument has no
use when the spill interfaces are called during the greedy allocator or even the
PrologEpilogInserter and can pass a null register in such cases.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D138656
Machine combiner supports generic reassociation only of associative and
commutative instructions, for example (A + X) + Y => (X + Y) + A. However, we
can extend this generic support to handle patterns like
(X + A) - Y => (X - Y) + A), where `-` is the inverse of `+`.
This patch adds interface functions to process reassociation patterns of
associative/commutative instructions and their inverse variants with minimal
changes in backends.
Differential Revision: https://reviews.llvm.org/D136754
This patch adds the following NFC fixes to PPCInstrInfo.cpp when getting the DefMI:
- Fix documentation error to state that we want to flag a use of register
between the def and the MI (in post-RA)
- Setting the DefMI to null if the DefMI is neither an LI or and ADDI
(while still being in SSA form).
In terms of setting the DefMI to null, this change aims to account for the
scenario of when we end up going through all operands on the machine instruction
MI and updating OpNoForForwarding accordingly once an ADDI is found as the DefMI.
It is possible that once an ADDI is found, we will continue to go through all
operands in attempts to find an LI, but end up looking at every operand until
we reach the end if we have not yet found an LI. In the case where the end is
reached and we never end up finding an LI/ADDI, DefMI would be pointing to the
last operand of MI while OpNoForForwarding would still be pointing at the
previous ADDI operand found. We reset DefMI to avoid having DefMI point to an
instruction that differs from the one represented by OpNoForForwarding.
Differential Revision: https://reviews.llvm.org/D137483
This patch adds spilling for the new WACC registers.
In order to get the spilling test to work the MMA instructions from Power 10 are
now supported for Future CPU except that they are all using the new WACC
registers instead of the ACC registers from Power 10.
Reviewed By: amyk, saghir
Differential Revision: https://reviews.llvm.org/D136728
This patch teaches getStoreOpcodesForSpillArray and
getLoadOpcodesForSpillArray to return ArrayRef. This way,
isLoadFromStackSlot and isStoreToStackSlot can use llvm::is_contained.
Summary: We currently optimize the comparison only in SSA, therefore we will miss some optimization opportunities where the input of comparison is lowered from COPY in post-RA.
Ie. ExpandPostRA::LowerCopy is called after PPCInstrInfo::optimizeCompareInstr.
This patch optimizes the comparison in post-RA and only the cases that compare against zero can be handled.
D131374 converts the comparison and its user to a compare against zero with the appropriate predicate on the branch, which creates additional opportunities for this patch.
Reviewed By: shchenz, lkail
Differential Revision: https://reviews.llvm.org/D131873
doesn't happened in peephole optimizer.
Summary: Converting a comparison against 1 or -1 into a comparison
against 0 can exploit record-form instructions for comparison optimization.
The conversion will happen only when a record-form instruction can be used
to replace the comparison during the peephole optimizer (see function optimizeCompareInstr).
In post-RA, we also want to optimize the comparison by using the record
form (see D131873) and it requires additional dataflow analysis to reliably
find uses of the CR register set.
It's reasonable to common the conversion for both peephole optimizer and
post-RA optimizer.
Converting to comparison against zero even when the optimization doesn't
happened in peephole optimizer may create additional opportunities for the
post-RA optimization.
Reviewed By: nemanjai
Differential Revision: https://reviews.llvm.org/D131374
LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpful for C++17 or later: `std::size` already has support for C-style
arrays.
Change call sites to use `std::size` instead.
Differential Revision: https://reviews.llvm.org/D133429
This patch fixes the following two bugs in `PPCInstrInfo::isSignOrZeroExtended` helper, which is used from sign-/zero-extension elimination in PPCMIPeephole pass.
- Registers defined by load with update (e.g. LBZU) were identified as already sign or zero-extended. But it is true only for the first def (loaded value) and not for the second def (i.e. updated pointer).
- Registers defined by ORIS/XORIS were identified as already sign-extended. But, it is not true for sign extension depending on the immediate (while it is ok for zero extension).
To handle the first case, the parameter for the helpers is changed from `MachineInstr` to a register number to distinguish first and second defs. Also, this patch moves the initialization of PPCMIPeepholePass to allow mir test case.
Reviewed By: nemanjai
Differential Revision: https://reviews.llvm.org/D40554
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.
Support allocation of huge stack frame(>2g) on PPC64.
For ELFv2 ABI on Linux, quoted from the spec 2.2.3.1 General Stack Frame Requirements
> There is no maximum stack frame size defined.
On AIX, XL allows such huge frame.
Reviewed By: #powerpc, nemanjai
Differential Revision: https://reviews.llvm.org/D107886
This reverts commit ef8206320769ad31422a803a0d6de6077fd231d2.
- It conflicts with the existing llvm::size in STLExtras, which will now
never be called.
- Calling it without llvm:: breaks C++17 compat
Currently, the floating point instructions that depend on
rounding mode are correctly marked in the PPC back end with
an implicit use of the RM register. Similarly, instructions
that explicitly define the register are marked with an
implicit def of the same register. So for the most part,
RM-using code won't be moved across RM-setting instructions.
However, calls are not marked as RM-setting instructions so
code can be moved across calls. This is generally desired,
but so is the ability to turn off this behaviour with an
appropriate option - and -frounding-math really should be
that option.
This patch provides a set of call instructions (for direct
and indirect calls) that are marked with an implicit def of
the RM register. These will be used for calls that are marked
with the strictfp attribute.
Differential revision: https://reviews.llvm.org/D111433
This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.
This allows us to ensure that Support doesn't have includes from MC/*.
Differential Revision: https://reviews.llvm.org/D111454
Stop using APInt constructors and methods that were soft-deprecated in
D109483. This fixes all the uses I found in llvm, except for the APInt
unit tests which should still test the deprecated methods.
Differential Revision: https://reviews.llvm.org/D110807
This patch marks splat immediate instructions XXSPLTIW and XXSPLTIDP as
rematerializable to prevent MachineLICM from moving them out of loops.
Reviewed By: lei, amy
Differential revision: https://reviews.llvm.org/D108823
This patch adds a fix to do early if conversion to select when
conditional branch not using physical register to prevent the crash when
expanding ISEL instruction.
Reviewed By: lei, kamaub, PowerPC
Differential revision: https://reviews.llvm.org/D108302
