A call to @llvm.trap can be expected to be cold (i.e. unlikely to be
reached in a normal program execution).
Outlining paths which unconditionally trap is an important memory
saving. As the hot/cold splitting pass (imho) should not treat all
noreturn calls as cold, explicitly mark @llvm.trap cold so that it can
be outlined.
Split out of https://reviews.llvm.org/D54244.
Differential Revision: https://reviews.llvm.org/D54329
llvm-svn: 346885
Summary:
This simplifies the code and moves everything to tablegen for consistency. This
also prepares the ground for adding issue counters.
Reviewers: gchatelet, john.brawn, jsji
Subscribers: nemanjai, mgorny, javed.absar, kbarton, tschuett, llvm-commits
Differential Revision: https://reviews.llvm.org/D54297
llvm-svn: 346489
Summary:
As a bonus, this arguably improves the code by making it simpler.
gcc 8 on Ubuntu 18.10 reports the following:
==39667==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7fffffff8ae0 at pc 0x555555dbfc68 bp 0x7fffffff8760 sp 0x7fffffff8750
WRITE of size 8 at 0x7fffffff8ae0 thread T0
#0 0x555555dbfc67 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider::_Alloc_hider(char*, std::allocator<char>&&) /usr/include/c++/8/bits/basic_string.h:149
#1 0x555555dbfc67 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&&) /usr/include/c++/8/bits/basic_string.h:542
#2 0x555555dbfc67 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > std::operator+<char, std::char_traits<char>, std::allocator<char> >(char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&&) /usr/include/c++/8/bits/basic_string.h:6009
#3 0x555555dbfc67 in searchableFieldType /home/nha/amd/build/san/llvm-src/utils/TableGen/SearchableTableEmitter.cpp:168
(...)
Address 0x7fffffff8ae0 is located in stack of thread T0 at offset 864 in frame
#0 0x555555dbef3f in searchableFieldType /home/nha/amd/build/san/llvm-src/utils/TableGen/SearchableTableEmitter.cpp:148
Reviewers: fhahn, simon_tatham, kparzysz
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D53931
llvm-svn: 345749
Before this patch, class PredicateExpander only knew how to expand simple
predicates that performed checks on instruction operands.
In particular, the new scheduling predicate syntax was not rich enough to
express checks like this one:
Foo(MI->getOperand(0).getImm()) == ExpectedVal;
Here, the immediate operand value at index zero is passed in input to function
Foo, and ExpectedVal is compared against the value returned by function Foo.
While this predicate pattern doesn't show up in any X86 model, it shows up in
other upstream targets. So, being able to support those predicates is
fundamental if we want to be able to modernize all the scheduling models
upstream.
With this patch, we allow users to specify if a register/immediate operand value
needs to be passed in input to a function as part of the predicate check. Now,
register/immediate operand checks all derive from base class CheckOperandBase.
This patch also changes where TIIPredicate definitions are expanded by the
instructon info emitter. Before, definitions were expanded in class
XXXGenInstrInfo (where XXX is a target name).
With the introduction of this new syntax, we may want to have TIIPredicates
expanded directly in XXXInstrInfo. That is because functions used by the new
operand predicates may only exist in the derived class (i.e. XXXInstrInfo).
This patch is a non functional change for the existing scheduling models.
In future, we will be able to use this richer syntax to better describe complex
scheduling predicates, and expose them to llvm-mca.
Differential Revision: https://reviews.llvm.org/D53880
llvm-svn: 345714
Summary:
The pfm counters are now in the ExegesisTarget rather than the
MCSchedModel (PR39165).
This also compresses the pfm counter tables (PR37068).
Reviewers: RKSimon, gchatelet
Subscribers: mgrang, llvm-commits
Differential Revision: https://reviews.llvm.org/D52932
llvm-svn: 345243
Summary:
Some targets have very long encodings and uint64_t isn't sufficient. uint128_t
isn't portable so such targets need to use an object instead.
There is one catch with this at the moment, no string of bits extracted
from the encoding may exceeed 64-bits. Fields are still permitted to
exceed 64-bits so long as they aren't one contiguous string of bits. If
this proves to be a problem then we can modify the generation of
fieldFromInstruction() calls to account for it but for now I've added an
assertion for this.
InsnType must either be integral or an APInt-like object that must:
* Have a static const max_size_in_bits equal to the number of bits in the encoding.
* be default-constructible and copy-constructible
* be constructible from a uint64_t (this is the key area the interface deviates
from APInt since this constructor does not take the bit width)
* be constructible from an APInt (this can be private)
* be convertible to uint64_t
* Support the ~, &,, ==, !=, and |= operators with other objects of the same type
* Support shift (<<, >>) with signed and unsigned integers on the RHS
* Support put (<<) to raw_ostream&
Reviewers: bogner, charukcs
Subscribers: nhaehnle, llvm-commits
Differential Revision: https://reviews.llvm.org/D52100
llvm-svn: 345056
Summary:
Replace its functionality with a TableGen InstrInfo relational
instruction mapping. Although arguably more complex than the TableGen
backend, the relational mapping is a smaller maintenance burden than a
TableGen backend.
Reviewers: aardappel, aheejin, dschuff
Subscribers: mgorny, sbc100, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D53307
llvm-svn: 344962
This patch adds the ability to identify instructions that are "move elimination
candidates". It also allows scheduling models to describe processor register
files that allow move elimination.
A move elimination candidate is an instruction that can be eliminated at
register renaming stage.
Each subtarget can specify which instructions are move elimination candidates
with the help of tablegen class "IsOptimizableRegisterMove" (see
llvm/Target/TargetInstrPredicate.td).
For example, on X86, BtVer2 allows both GPR and MMX/SSE moves to be eliminated.
The definition of 'IsOptimizableRegisterMove' for BtVer2 looks like this:
```
def : IsOptimizableRegisterMove<[
InstructionEquivalenceClass<[
// GPR variants.
MOV32rr, MOV64rr,
// MMX variants.
MMX_MOVQ64rr,
// SSE variants.
MOVAPSrr, MOVUPSrr,
MOVAPDrr, MOVUPDrr,
MOVDQArr, MOVDQUrr,
// AVX variants.
VMOVAPSrr, VMOVUPSrr,
VMOVAPDrr, VMOVUPDrr,
VMOVDQArr, VMOVDQUrr
], CheckNot<CheckSameRegOperand<0, 1>> >
]>;
```
Definitions of IsOptimizableRegisterMove from processor models of a same
Target are processed by the SubtargetEmitter to auto-generate a target-specific
override for each of the following predicate methods:
```
bool TargetSubtargetInfo::isOptimizableRegisterMove(const MachineInstr *MI)
const;
bool MCInstrAnalysis::isOptimizableRegisterMove(const MCInst &MI, unsigned
CPUID) const;
```
By default, those methods return false (i.e. conservatively assume that there
are no move elimination candidates).
Tablegen class RegisterFile has been extended with the following information:
- The set of register classes that allow move elimination.
- Maxium number of moves that can be eliminated every cycle.
- Whether move elimination is restricted to moves from registers that are
known to be zero.
This patch is structured in three part:
A first part (which is mostly boilerplate) adds the new
'isOptimizableRegisterMove' target hooks, and extends existing register file
descriptors in MC by introducing new fields to describe properties related to
move elimination.
A second part, uses the new tablegen constructs to describe move elimination in
the BtVer2 scheduling model.
A third part, teaches llm-mca how to query the new 'isOptimizableRegisterMove'
hook to mark instructions that are candidates for move elimination. It also
teaches class RegisterFile how to describe constraints on move elimination at
PRF granularity.
llvm-mca tests for btver2 show differences before/after this patch.
Differential Revision: https://reviews.llvm.org/D53134
llvm-svn: 344334
Summary:
The predicate function is added in InlinePatternFragments, no need to
do it here. As a result, all uses of addPredicateFn are located in
InlinePatternFragments.
Test confirmed that there are no changes to generated files when
building all (non-experimental) targets.
Change-Id: I720e42e045ca596eb0aa339fb61adf6fe71034d5
Reviewers: arsenm, rampitec, RKSimon, craig.topper, hfinkel, uweigand
Subscribers: wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D51993
llvm-svn: 343977
There are a few leftovers in rL343163 which span two lines. This commit
changes these llvm::sort(C.begin(), C.end, ...) to llvm::sort(C, ...)
llvm-svn: 343426
Summary:
By using the existing isCodeGenOnly bit in the tablegen defs, as
suggested by tlively in https://reviews.llvm.org/D51662
Tested: llvm-lit -v `find test -name WebAssembly`
Reviewers: tlively
Subscribers: dschuff, sbc100, jgravelle-google, aheejin, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D52373
llvm-svn: 342772
Summary:
This ensures we have the non-register version of the instruction.
The stack version of call_indirect now wants a type index argument,
so that has been added in the existing tests.
Tested:
llvm-lit -v `find test -name WebAssembly`
Reviewers: dschuff
Subscribers: sbc100, jgravelle-google, aheejin, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D51662
llvm-svn: 342753
The reason why build #25777 might have failed is because the SmallVector move
constructor is _not_ noexcept, and the stl implementation used by that buildbot
calls _VSTD::move_if_noexcept() (according to the backtrace).
OpcodeInfo has a default move constructor, and the copy constructor is deleted.
However, as far as I can see, SmallVector doesn't declare a noexcept move
constructor. So, what I believe it is happening here is that,
_VSTD::move_if_noexcept() returns an lvalue reference and not an rvalue
reference.
This eventually triggers a copy that fails to compile.
Hopefully, using a std::vector instead of SmallVector (as it was originally
suggested by Simon in the code review) should be enough to unbreak the buildbot.
llvm-svn: 342561
This patch adds the ability for processor models to describe dependency breaking
instructions.
Different processors may specify a different set of dependency-breaking
instructions.
That means, we cannot assume that all processors of the same target would use
the same rules to classify dependency breaking instructions.
The main goal of this patch is to provide the means to describe dependency
breaking instructions directly via tablegen, and have the following
TargetSubtargetInfo hooks redefined in overrides by tabegen'd
XXXGenSubtargetInfo classes (here, XXX is a Target name).
```
virtual bool isZeroIdiom(const MachineInstr *MI, APInt &Mask) const {
return false;
}
virtual bool isDependencyBreaking(const MachineInstr *MI, APInt &Mask) const {
return isZeroIdiom(MI);
}
```
An instruction MI is a dependency-breaking instruction if a call to method
isDependencyBreaking(MI) on the STI (TargetSubtargetInfo object) evaluates to
true. Similarly, an instruction MI is a special case of zero-idiom dependency
breaking instruction if a call to STI.isZeroIdiom(MI) returns true.
The extra APInt is used for those targets that may want to select which machine
operands have their dependency broken (see comments in code).
Note that by default, subtargets don't know about the existence of
dependency-breaking. In the absence of external information, those method calls
would always return false.
A new tablegen class named STIPredicate has been added by this patch to let
processor models classify instructions that have properties in common. The idea
is that, a MCInstrPredicate definition can be used to "generate" an instruction
equivalence class, with the idea that instructions of a same class all have a
property in common.
STIPredicate definitions are essentially a collection of instruction equivalence
classes.
Also, different processor models can specify a different variant of the same
STIPredicate with different rules (i.e. predicates) to classify instructions.
Tablegen backends (in this particular case, the SubtargetEmitter) will be able
to process STIPredicate definitions, and automatically generate functions in
XXXGenSubtargetInfo.
This patch introduces two special kind of STIPredicate classes named
IsZeroIdiomFunction and IsDepBreakingFunction in tablegen. It also adds a
definition for those in the BtVer2 scheduling model only.
This patch supersedes the one committed at r338372 (phabricator review: D49310).
The main advantages are:
- We can describe subtarget predicates via tablegen using STIPredicates.
- We can describe zero-idioms / dep-breaking instructions directly via
tablegen in the scheduling models.
In future, the STIPredicates framework can be used for solving other problems.
Examples of future developments are:
- Teach how to identify optimizable register-register moves
- Teach how to identify slow LEA instructions (each subtarget defining its own
concept of "slow" LEA).
- Teach how to identify instructions that have undocumented false dependencies
on the output registers on some processors only.
It is also (in my opinion) an elegant way to expose knowledge to both external
tools like llvm-mca, and codegen passes.
For example, machine schedulers in LLVM could reuse that information when
internally constructing the data dependency graph for a code region.
This new design feature is also an "opt-in" feature. Processor models don't have
to use the new STIPredicates. It has all been designed to be as unintrusive as
possible.
Differential Revision: https://reviews.llvm.org/D52174
llvm-svn: 342555
Further extension to D51035, this patch avoids all repeated predicates[] matching by caching as it collects the patterns that have multiple variants.
Saves around 25secs in debug builds of x86 -gen-dag-isel.
Differential Revision: https://reviews.llvm.org/D51839
llvm-svn: 342467
Summary:
Now uses the StackBased bit from the tablegen defs to identify
stack instructions (and ignore register based or non-wasm instructions).
Also changed how we store operands, since we now have up to 16 of them
per instruction. To not cause static data bloat, these are compressed
into a tiny table.
+ a few other cleanups.
Tested:
- MCTest
- llvm-lit -v `find test -name WebAssembly`
Reviewers: dschuff, jgravelle-google, sunfish, tlively
Subscribers: sbc100, aheejin, llvm-commits
Differential Revision: https://reviews.llvm.org/D51320
llvm-svn: 341081
Summary:
Add comments to help readers avoid having to read tablegen backends to
understand the code. Also remove unecessary breaks from the output.
Reviewers: dschuff, aheejin
Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D51371
llvm-svn: 340864
CodeGenDAGPatterns::GenerateVariants is a costly function in many tblgen commands (33.87% of the total runtime of x86 -gen-dag-isel), and due to the O(N^2) nature of the function, there are a high number of repeated comparisons of the pattern's vector<Predicate>.
This initial patch at least avoids repeating these comparisons for every Variant in a pattern. I began investigating caching all the matches before entering the loop but hit issues with how best to store the data and how to update the cache as patterns were added.
Saves around 15secs in debug builds of x86 -gen-dag-isel.
Differential Revision: https://reviews.llvm.org/D51035
llvm-svn: 340837
Summary:
The new stackification backend generates the giant switch statement
used to translate instructions to their stackified forms. I did this
because it was more interesting than adding all the different vector
versions of the various SIMD instructions to the switch statment
manually.
Reviewers: aardappel, aheejin, dschuff
Subscribers: mgorny, sbc100, jgravelle-google, sunfish, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D51318
llvm-svn: 340781
Summary:
So far, `isReturn` property is used to mean both a return instruction
from a functon and the end of an EH scope, a scope that starts with a EH
scope entry BB and ends with a catchret or a cleanupret instruction.
Because WinEH uses funclets, all EH-scope-ending instructions are also
real return instruction from a function. But for wasm, they only serve
as the end marker of an EH scope but not a return instruction that
exits a function. This mismatch caused incorrect prolog and epilog
generation in wasm EH scopes. This patch fixes this.
This patch is in the same vein with rL333045, which splits
`MachineBasicBlock::isEHFuncletEntry` into `isEHFuncletEntry` and
`isEHScopeEntry`.
Reviewers: dschuff
Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D50653
llvm-svn: 340325
We were just caching the MVT set of legal types, then every call creating a new TypeSetByHwMode with it and passing it back on the stack. There's no need to do this - we can create and cache the whole TypeSetByHwMode once and return a const reference to it each time.
Additionally, TypeInfer::expandOverloads wasn't making use of the fact that the cache just contains a default mode containing all the types.
Saves up to 30secs in debug builds of x86 -gen-dag-isel.
Differential Revision: https://reviews.llvm.org/D50903
llvm-svn: 340042
This operator is called a great deal, by checking for the cheap isSimple equality cases first (a common occurrence) we can improve performance as we avoid a lot of std::map find/iteration in hasDefault.
isSimple also means that a default value is present, so we can avoid some hasDefault calls.
This also avoids a rather dodgy piece of logic that was checking for isSimple() && !VTS.isSimple() but not the inverse - it now uses the general hasDefault mode comparison test instead.
Saves around 15secs in debug builds of x86 -gen-dag-isel.
Differential Revision: https://reviews.llvm.org/D50841
llvm-svn: 339890
I noticed this during profiling of tablegen (PR28222) that we were calling Child->getType(0) which creates a ValueTypeByHwMode on the fly from the requested internal TypeSetByHwMode type and returns it by value, we then treat it as a TypeSetByHwMode reference which involves constructing a new TypeSetByHwMode on the stack with a large amount of std::map iterating/copying all along the way.
I am not an expert on tablegen, but AFAICT this is all unnecessary and we should be calling Child->getExtType(0) which returns the original TypeSetByHwMode by reference.
This gives me a 90sec reduction in msvc debug builds of x86 -gen-dag-isel.
Differential Revision: https://reviews.llvm.org/D50789
llvm-svn: 339812
This patch removes redundant template argument `TargetName` from TIIPredicate.
Tablegen can always infer the target name from the context. So we don't need to
force users of TIIPredicate to always specify it.
This allows us to better modularize the tablegen class hierarchy for the
so-called "function predicates". class FunctionPredicateBase has been added; it
is currently used as a building block for TIIPredicates. However, I plan to
reuse that class to model other function predicate classes too (i.e. not just
TIIPredicates). For example, this can be a first step towards implementing
proper support for dependency breaking instructions in tablegen.
This patch also adds a verification step on TIIPredicates in tablegen.
We cannot have multiple TIIPredicates with the same name. Otherwise, this will
cause build errors later on, when tablegen'd .inc files are included by cpp
files and then compiled.
Differential Revision: https://reviews.llvm.org/D50708
llvm-svn: 339706
The behavior in 64-bit mode is different between Intel and AMD CPUs. Intel ignores the 0x66 prefix. AMD does not. objump doesn't ignore the 0x66 prefix. Since LLVM aims to match objdump behavior, we should do the same.
While I was trying to fix this I had change brtarget16/32 to use ENCODING_IW/ID instead of ENCODING_Iv to get the 0x66+REX.W case to act sort of sanely. It's still wrong, but that's a problem for another day.
The change in encoding exposed the fact that 16-bit mode disassembly of relative jumps was creating JMP_4 with a 2 byte immediate. It should have been JMP_2. From just printing you can't tell the difference, but if you dumped the encoding it wouldn't have matched what we started with.
While fixing that, it exposed that jo/jno opcodes were missing from the switch that this patch deleted and there were no test cases for them.
Fixes PR38537.
llvm-svn: 339622
This is a follow-up of r339552.
As pointed out by Craig in D50566, we don't need a formatted_raw_ostream to
indent strings. We can use instead raw_ostream::indent().
Internally, class PredicateExpander already keeps track of the current
indentation level. Also, the grammar for predicates is well parenthesized, and
therefore we don't need to use a formatted_raw_ostream to continuously track the
column number. Instead we can safely replace all the uses of
formatted_raw_ostream::PadToColumn() with uses of raw_ostream::indent().
By replacing formatted_raw_ostream with a simpler raw_ostream, we also avoid the
implicit check on the newline character on every print to stream.
No functional change intended.
llvm-svn: 339577
This patch refactors the logic that expands predicates of a variant scheduling
class.
The idea is to improve the readability of the auto-generated code by removing
redundant parentheses around predicate expressions, and by removing redundant
if(true) statements.
This patch replaces the definition of NoSchedPred in TargetSchedule.td with an
instance of MCSchedPredicate. The new definition is sematically equivalent to
the previous one. The main difference is that now SubtargetEmitter knows that it
represents predicate "true".
Before this patch, we always generated an if (true) for the default transition
of a variant scheduling class.
Example (taken from AArch64GenSubtargetInfo.inc) :
```
if (SchedModel->getProcessorID() == 3) { // CycloneModel
if ((TII->isScaledAddr(*MI)))
return 927; // (WriteIS_WriteLD)_ReadBaseRS
if ((true))
return 928; // WriteLD_ReadDefault
}
```
Extra parentheses were also generated around the predicate expressions.
With this patch, we get the following auto-generated checks:
```
if (SchedModel->getProcessorID() == 3) { // CycloneModel
if (TII->isScaledAddr(*MI))
return 927; // (WriteIS_WriteLD)_ReadBaseRS
return 928; // WriteLD_ReadDefault
}
```
The new auto-generated code behaves exactly the same as before. So, technically
this is a non functional change.
Differential revision: https://reviews.llvm.org/D50566
llvm-svn: 339552
