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[globalisel][legalizerinfo] Follow up on post-commit review comments after r323681

* Document most API's
* Delete a useless function call
* Fix a discrepancy between the single and multi-opcode variants of
  getActionDefinitions().
  The multi-opcode variant now requires that more than one opcode is requested.
  Previously it acted much like the single-opcode form but unnecessarily
  enforced the requirements of the multi-opcode form.

llvm-svn: 325067
This commit is contained in:
Daniel Sanders 2018-02-13 23:02:44 +00:00
parent a08a14762d
commit e6e2436fba
3 changed files with 106 additions and 3 deletions

View File

@ -144,25 +144,46 @@ using LegalizeMutation =
std::function<std::pair<unsigned, LLT>(const LegalityQuery &)>;
namespace LegalityPredicates {
/// True iff P0 and P1 are true.
LegalityPredicate all(LegalityPredicate P0, LegalityPredicate P1);
/// True iff the given type index is one of the specified types.
LegalityPredicate typeInSet(unsigned TypeIdx,
std::initializer_list<LLT> TypesInit);
/// True iff the given types for the given pair of type indexes is one of the
/// specified type pairs.
LegalityPredicate
typePairInSet(unsigned TypeIdx0, unsigned TypeIdx1,
std::initializer_list<std::pair<LLT, LLT>> TypesInit);
/// True iff the specified type index is a scalar.
LegalityPredicate isScalar(unsigned TypeIdx);
/// True iff the specified type index is a scalar that's narrower than the given
/// size.
LegalityPredicate narrowerThan(unsigned TypeIdx, unsigned Size);
/// True iff the specified type index is a scalar that's wider than the given
/// size.
LegalityPredicate widerThan(unsigned TypeIdx, unsigned Size);
/// True iff the specified type index is a scalar whose size is not a power of
/// 2.
LegalityPredicate sizeNotPow2(unsigned TypeIdx);
/// True iff the specified type index is a vector whose element count is not a
/// power of 2.
LegalityPredicate numElementsNotPow2(unsigned TypeIdx);
} // end namespace LegalityPredicates
namespace LegalizeMutations {
/// Select this specific type for the given type index.
LegalizeMutation changeTo(unsigned TypeIdx, LLT Ty);
/// Widen the type for the given type index to the next power of 2.
LegalizeMutation widenScalarToNextPow2(unsigned TypeIdx, unsigned Min = 0);
/// Add more elements to the type for the given type index to the next power of
/// 2.
LegalizeMutation moreElementsToNextPow2(unsigned TypeIdx, unsigned Min = 0);
} // end namespace LegalizeMutations
/// A single rule in a legalizer info ruleset.
/// The specified action is chosen when the predicate is true. Where appropriate
/// for the action (e.g. for WidenScalar) the new type is selected using the
/// given mutator.
class LegalizeRule {
LegalityPredicate Predicate;
LegalizeAction Action;
@ -173,11 +194,14 @@ public:
LegalizeMutation Mutation = nullptr)
: Predicate(Predicate), Action(Action), Mutation(Mutation) {}
/// Test whether the LegalityQuery matches.
bool match(const LegalityQuery &Query) const {
return Predicate(Query);
}
LegalizeAction getAction() const { return Action; }
/// Determine the change to make.
std::pair<unsigned, LLT> determineMutation(const LegalityQuery &Query) const {
if (Mutation)
return Mutation(Query);
@ -200,32 +224,48 @@ class LegalizeRuleSet {
static bool always(const LegalityQuery &) { return true; }
/// Use the given action when the predicate is true.
/// Action should not be an action that requires mutation.
LegalizeRuleSet &actionIf(LegalizeAction Action,
LegalityPredicate Predicate) {
add({Predicate, Action});
return *this;
}
/// Use the given action when the predicate is true.
/// Action should not be an action that requires mutation.
LegalizeRuleSet &actionIf(LegalizeAction Action, LegalityPredicate Predicate,
LegalizeMutation Mutation) {
add({Predicate, Action, Mutation});
return *this;
}
/// Use the given action when type index 0 is any type in the given list.
/// Action should not be an action that requires mutation.
LegalizeRuleSet &actionFor(LegalizeAction Action,
std::initializer_list<LLT> Types) {
using namespace LegalityPredicates;
return actionIf(Action, typeInSet(0, Types));
}
/// Use the given action when type indexes 0 and 1 is any type pair in the
/// given list.
/// Action should not be an action that requires mutation.
LegalizeRuleSet &
actionFor(LegalizeAction Action,
std::initializer_list<std::pair<LLT, LLT>> Types) {
using namespace LegalityPredicates;
return actionIf(Action, typePairInSet(0, 1, Types));
}
/// Use the given action when type indexes 0 and 1 are both in the given list.
/// That is, the type pair is in the cartesian product of the list.
/// Action should not be an action that requires mutation.
LegalizeRuleSet &actionForCartesianProduct(LegalizeAction Action,
std::initializer_list<LLT> Types) {
using namespace LegalityPredicates;
return actionIf(Action, all(typeInSet(0, Types), typeInSet(1, Types)));
}
/// Use the given action when type indexes 0 and 1 are both their respective
/// lists.
/// That is, the type pair is in the cartesian product of the lists
/// Action should not be an action that requires mutation.
LegalizeRuleSet &
actionForCartesianProduct(LegalizeAction Action,
std::initializer_list<LLT> Types0,
@ -247,24 +287,32 @@ public:
}
unsigned getAlias() const { return AliasOf; }
// Primitive rule definition functions
/// The instruction is legal if predicate is true.
LegalizeRuleSet &legalIf(LegalityPredicate Predicate) {
return actionIf(LegalizeAction::Legal, Predicate);
}
/// The instruction is legal when type index 0 is any type in the given list.
LegalizeRuleSet &legalFor(std::initializer_list<LLT> Types) {
return actionFor(LegalizeAction::Legal, Types);
}
/// The instruction is legal when type indexes 0 and 1 is any type pair in the
/// given list.
LegalizeRuleSet &legalFor(std::initializer_list<std::pair<LLT, LLT>> Types) {
return actionFor(LegalizeAction::Legal, Types);
}
/// The instruction is legal when type indexes 0 and 1 are both in the given
/// list. That is, the type pair is in the cartesian product of the list.
LegalizeRuleSet &legalForCartesianProduct(std::initializer_list<LLT> Types) {
return actionForCartesianProduct(LegalizeAction::Legal, Types);
}
/// The instruction is legal when type indexes 0 and 1 are both their
/// respective lists.
LegalizeRuleSet &legalForCartesianProduct(std::initializer_list<LLT> Types0,
std::initializer_list<LLT> Types1) {
return actionForCartesianProduct(LegalizeAction::Legal, Types0, Types1);
}
/// Like legalIf, but for the Libcall action.
LegalizeRuleSet &libcallIf(LegalityPredicate Predicate) {
return actionIf(LegalizeAction::Libcall, Predicate);
}
@ -285,24 +333,33 @@ public:
return actionForCartesianProduct(LegalizeAction::Libcall, Types0, Types1);
}
/// Widen the scalar to the one selected by the mutation if the predicate is
/// true.
LegalizeRuleSet &widenScalarIf(LegalityPredicate Predicate,
LegalizeMutation Mutation) {
return actionIf(LegalizeAction::WidenScalar, Predicate, Mutation);
}
/// Narrow the scalar to the one selected by the mutation if the predicate is
/// true.
LegalizeRuleSet &narrowScalarIf(LegalityPredicate Predicate,
LegalizeMutation Mutation) {
return actionIf(LegalizeAction::NarrowScalar, Predicate, Mutation);
}
/// Add more elements to reach the type selected by the mutation if the
/// predicate is true.
LegalizeRuleSet &moreElementsIf(LegalityPredicate Predicate,
LegalizeMutation Mutation) {
return actionIf(LegalizeAction::MoreElements, Predicate, Mutation);
}
/// Remove elements to reach the type selected by the mutation if the
/// predicate is true.
LegalizeRuleSet &fewerElementsIf(LegalityPredicate Predicate,
LegalizeMutation Mutation) {
return actionIf(LegalizeAction::FewerElements, Predicate, Mutation);
}
/// The instruction is unsupported.
LegalizeRuleSet &unsupported() {
return actionIf(LegalizeAction::Unsupported, always);
}
@ -325,7 +382,8 @@ public:
return actionForCartesianProduct(LegalizeAction::Custom, Types0, Types1);
}
// Convenience rule definition functions
/// Widen the scalar to the next power of two that is at least MinSize.
/// No effect if the type is not a scalar or is a power of two.
LegalizeRuleSet &widenScalarToNextPow2(unsigned TypeIdx, unsigned MinSize = 0) {
using namespace LegalityPredicates;
return widenScalarIf(
@ -338,6 +396,7 @@ public:
return narrowScalarIf(isScalar(TypeIdx), Mutation);
}
/// Ensure the scalar is at least as wide as Ty.
LegalizeRuleSet &minScalar(unsigned TypeIdx, const LLT &Ty) {
using namespace LegalityPredicates;
using namespace LegalizeMutations;
@ -345,6 +404,7 @@ public:
changeTo(TypeIdx, Ty));
}
/// Ensure the scalar is at most as wide as Ty.
LegalizeRuleSet &maxScalar(unsigned TypeIdx, const LLT &Ty) {
using namespace LegalityPredicates;
using namespace LegalizeMutations;
@ -352,6 +412,9 @@ public:
changeTo(TypeIdx, Ty));
}
/// Conditionally limit the maximum size of the scalar.
/// For example, when the maximum size of one type depends on the size of
/// another such as extracting N bits from an M bit container.
LegalizeRuleSet &maxScalarIf(LegalityPredicate Predicate, unsigned TypeIdx, const LLT &Ty) {
using namespace LegalityPredicates;
using namespace LegalizeMutations;
@ -363,6 +426,7 @@ public:
changeTo(TypeIdx, Ty));
}
/// Limit the range of scalar sizes to MinTy and MaxTy.
LegalizeRuleSet &clampScalar(unsigned TypeIdx, const LLT &MinTy, const LLT &MaxTy) {
assert(MinTy.isScalar() && MaxTy.isScalar() && "Expected scalar types");
@ -370,12 +434,16 @@ public:
.maxScalar(TypeIdx, MaxTy);
}
/// Add more elements to the vector to reach the next power of two.
/// No effect if the type is not a vector or the element count is a power of
/// two.
LegalizeRuleSet &moreElementsToNextPow2(unsigned TypeIdx) {
using namespace LegalityPredicates;
return moreElementsIf(numElementsNotPow2(TypeIdx),
LegalizeMutations::moreElementsToNextPow2(TypeIdx));
}
/// Limit the number of elements in EltTy vectors to at least MinElements.
LegalizeRuleSet &clampMinNumElements(unsigned TypeIdx, const LLT &EltTy,
unsigned MinElements) {
return moreElementsIf(
@ -390,6 +458,7 @@ public:
TypeIdx, LLT::vector(MinElements, VecTy.getScalarSizeInBits()));
});
}
/// Limit the number of elements in EltTy vectors to at most MaxElements.
LegalizeRuleSet &clampMaxNumElements(unsigned TypeIdx, const LLT &EltTy,
unsigned MaxElements) {
return fewerElementsIf(
@ -404,6 +473,12 @@ public:
TypeIdx, LLT::vector(MaxElements, VecTy.getScalarSizeInBits()));
});
}
/// Limit the number of elements for the given vectors to at least MinTy's
/// number of elements and at most MaxTy's number of elements.
///
/// No effect if the type is not a vector or does not have the same element
/// type as the constraints.
/// The element type of MinTy and MaxTy must match.
LegalizeRuleSet &clampNumElements(unsigned TypeIdx, const LLT &MinTy,
const LLT &MaxTy) {
assert(MinTy.getElementType() == MaxTy.getElementType() &&
@ -414,11 +489,14 @@ public:
.clampMaxNumElements(TypeIdx, EltTy, MaxTy.getNumElements());
}
/// Fallback on the previous implementation. This should only be used while
/// porting a rule.
LegalizeRuleSet &fallback() {
add({always, LegalizeAction::UseLegacyRules});
return *this;
}
/// Apply the ruleset to the given LegalityQuery.
LegalizeActionStep apply(const LegalityQuery &Query) const;
};
@ -593,8 +671,30 @@ public:
LegalizeAction DecreaseAction,
LegalizeAction IncreaseAction);
/// Get the action definitions for the given opcode. Use this to run a
/// LegalityQuery through the definitions.
const LegalizeRuleSet &getActionDefinitions(unsigned Opcode) const;
/// Get the action definition builder for the given opcode. Use this to define
/// the action definitions.
///
/// It is an error to request an opcode that has already been requested by the
/// multiple-opcode variant.
LegalizeRuleSet &getActionDefinitionsBuilder(unsigned Opcode);
/// Get the action definition builder for the given set of opcodes. Use this
/// to define the action definitions for multiple opcodes at once. The first
/// opcode given will be considered the representative opcode and will hold
/// the definitions whereas the other opcodes will be configured to refer to
/// the representative opcode. This lowers memory requirements and very
/// slightly improves performance.
///
/// It would be very easy to introduce unexpected side-effects as a result of
/// this aliasing if it were permitted to request different but intersecting
/// sets of opcodes but that is difficult to keep track of. It is therefore an
/// error to request the same opcode twice using this API, to request an
/// opcode that already has definitions, or to use the single-opcode API on an
/// opcode that has already been requested by this API.
LegalizeRuleSet &
getActionDefinitionsBuilder(std::initializer_list<unsigned> Opcodes);
void aliasActionDefinitions(unsigned OpcodeTo, unsigned OpcodeFrom);

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@ -261,6 +261,10 @@ LegalizeRuleSet &LegalizerInfo::getActionDefinitionsBuilder(
std::initializer_list<unsigned> Opcodes) {
unsigned Representative = *Opcodes.begin();
assert(Opcodes.begin() != Opcodes.end() &&
Opcodes.begin() + 1 != Opcodes.end() &&
"Initializer list must have at least two opcodes");
for (auto I = Opcodes.begin() + 1, E = Opcodes.end(); I != E; ++I)
aliasActionDefinitions(Representative, *I);

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@ -240,7 +240,6 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST) {
getActionDefinitionsBuilder(G_ATOMIC_CMPXCHG)
.legalForCartesianProduct({s8, s16, s32, s64}, {p0});
}
getActionDefinitionsBuilder(G_ATOMIC_CMPXCHG);
if (ST.hasLSE()) {
for (auto Ty : {s8, s16, s32, s64}) {