#include "circt/Dialect/Comb/CombOps.h"
#include "circt/Dialect/HW/HWAttributes.h"
#include "circt/Dialect/HW/HWOps.h"
#include "circt/Support/Naming.h"
#include "mlir/IR/Diagnostics.h"
#include "mlir/IR/Matchers.h"
#include "mlir/IR/PatternMatch.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/TypeSwitch.h"
#include "llvm/Support/KnownBits.h"

Include dependency graph for CombFolds.cpp:

Functions
static bool	isOpTriviallyRecursive (Operation *op)

static Value	createGenericOp (Location loc, OperationName name, ArrayRef< Value > operands, OpBuilder &builder)
	Create a new instance of a generic operation that only has value operands, and has a single result value whose type matches the first operand.

static TypedAttr	getIntAttr (const APInt &value, MLIRContext *context)

static void	getConcatOperands (Value v, SmallVectorImpl< Value > &result)
	Flatten concat and mux operands into a vector.

static bool	hasSVAttributes (Operation *op)

template<typename SubType >
static ComplementMatcher< SubType >	m_Complement (const SubType &subExpr)

static bool	shouldBeFlattened (Operation *op)
	Return true if the op will be flattened afterwards.

static bool	tryFlatteningOperands (Operation *op, PatternRewriter &rewriter)
	Flattens a single input in `op` if `hasOneUse` is true and it can be defined as an Op.

static std::pair< size_t, size_t >	getLowestBitAndHighestBitRequired (Operation *op, bool narrowTrailingBits, size_t originalOpWidth)

template<class OpTy >
static bool	narrowOperationWidth (OpTy op, bool narrowTrailingBits, PatternRewriter &rewriter)

static Attribute	constFoldBinaryOp (ArrayRef< Attribute > operands, hw::PEO paramOpcode)
	Performs constant folding `calculate` with element-wise behavior on the two attributes in `operands` and returns the result if possible.

static LogicalResult	extractConcatToConcatExtract (ExtractOp op, ConcatOp innerCat, PatternRewriter &rewriter)

static bool	extractFromReplicate (ExtractOp op, ReplicateOp replicate, PatternRewriter &rewriter)

static Attribute	constFoldAssociativeOp (ArrayRef< Attribute > operands, hw::PEO paramOpcode)

static bool	canonicalizeLogicalCstWithConcat (Operation *logicalOp, size_t concatIdx, const APInt &cst, PatternRewriter &rewriter)
	When we find a logical operation (and, or, xor) with a constant e.g.

static bool	canCombineOppositeBinCmpIntoConstant (OperandRange operands)

template<typename Op >
static Value	getCommonOperand (Op op)
	Returns a single common operand that all inputs of the operation `op` can be traced back to, or an empty `Value` if no such operand exists.

template<typename Op >
static bool	canonicalizeIdempotentInputs (Op op, PatternRewriter &rewriter)
	Canonicalize an idempotent operation `op` so that only one input of any kind occurs.

static void	canonicalizeXorIcmpTrue (XorOp op, unsigned icmpOperand, PatternRewriter &rewriter)

template<class Op , bool isSigned>
static OpFoldResult	foldDiv (Op op, ArrayRef< Attribute > constants)

template<class Op , bool isSigned>
static OpFoldResult	foldMod (Op op, ArrayRef< Attribute > constants)

static bool	getMuxChainCondConstant (Value cond, Value indexValue, bool isInverted, std::function< void(hw::ConstantOp)> constantFn)
	Check to see if the condition to the specified mux is an equality comparison `indexValue` and one or more constants.

static Value	extractOperandFromFullyAssociative (Operation *fullyAssoc, size_t operandNo, PatternRewriter &rewriter)
	Given a fully associative variadic operation like (a+b+c+d), break the expression into two parts, one without the specified operand (e.g.

static bool	foldCommonMuxValue (MuxOp op, bool isTrueOperand, PatternRewriter &rewriter)
	Fold things like `mux(cond, x\|y\|z\|a, a)` -> `(x\|y\|z)&replicate(cond)\|a` and `mux(cond, a, x\|y\|z\|a) ->`(x\|y\|z)&replicate(~cond) \| a` (when isTrueOperand is true.

static bool	foldCommonMuxOperation (MuxOp mux, Operation trueOp, Operation falseOp, PatternRewriter &rewriter)
	This function is invoke when we find a mux with true/false operations that have the same opcode.

static bool	foldMuxOfUniformArrays (MuxOp op, PatternRewriter &rewriter)

static bool	assumeMuxCondInOperand (Value muxCond, Value muxValue, bool constCond, PatternRewriter &rewriter)
	If the mux condition is an operand to the op defining its true or false value, replace the condition with 1 or 0.

static bool	applyCmpPredicate (ICmpPredicate predicate, const APInt &lhs, const APInt &rhs)

static bool	applyCmpPredicateToEqualOperands (ICmpPredicate predicate)

template<typename Range >
static size_t	computeCommonPrefixLength (const Range &a, const Range &b)

static size_t	getTotalWidth (ArrayRef< Value > operands)

static LogicalResult	matchAndRewriteCompareConcat (ICmpOp op, Operation lhs, Operation rhs, PatternRewriter &rewriter)
	Reduce the strength icmp(concat(...), concat(...)) by doing a element-wise comparison on common prefix and suffixes.

static void	combineEqualityICmpWithKnownBitsAndConstant (ICmpOp cmpOp, const KnownBits &bitAnalysis, const APInt &rhsCst, PatternRewriter &rewriter)
	Given an equality comparison with a constant value and some operand that has known bits, simplify the comparison to check only the unknown bits of the input.

static void	combineEqualityICmpWithXorOfConstant (ICmpOp cmpOp, XorOp xorOp, const APInt &rhs, PatternRewriter &rewriter)

Function Documentation

◆ applyCmpPredicate()

static bool applyCmpPredicate	(	ICmpPredicate	predicate,
		const APInt &	lhs,
		const APInt &	rhs
	)

static

Definition at line 2742 of file CombFolds.cpp.

◆ applyCmpPredicateToEqualOperands()

static bool applyCmpPredicateToEqualOperands ( ICmpPredicate predicate )

static

Definition at line 2779 of file CombFolds.cpp.

Referenced by matchAndRewriteCompareConcat().

◆ assumeMuxCondInOperand()

static bool assumeMuxCondInOperand	(	Value	muxCond,
		Value	muxValue,
		bool	constCond,
		PatternRewriter &	rewriter
	)

static

If the mux condition is an operand to the op defining its true or false value, replace the condition with 1 or 0.

Definition at line 2360 of file CombFolds.cpp.

References hw.ConstantOp::create().

◆ canCombineOppositeBinCmpIntoConstant()

static bool canCombineOppositeBinCmpIntoConstant ( OperandRange operands )

static

Definition at line 804 of file CombFolds.cpp.

◆ canonicalizeIdempotentInputs()

template<typename Op >

static bool canonicalizeIdempotentInputs	(	Op	op,
		PatternRewriter &	rewriter
	)

static

Canonicalize an idempotent operation op so that only one input of any kind occurs.

Example: and(x, y, x, z) -> and(x, y, z)

Definition at line 914 of file CombFolds.cpp.

◆ canonicalizeLogicalCstWithConcat()

static bool canonicalizeLogicalCstWithConcat	(	Operation *	logicalOp,
		size_t	concatIdx,
		const APInt &	cst,
		PatternRewriter &	rewriter
	)

static

When we find a logical operation (and, or, xor) with a constant e.g.

X & 42, we want to push the constant into the computation of X if it leads to simplification.

This function handles the case where the logical operation has a concat operand. We check to see if we can simplify the concat, e.g. when it has constant operands.

This returns true when a simplification happens.

Definition at line 726 of file CombFolds.cpp.

References assert(), hw.ConstantOp::create(), createGenericOp(), and circt::replaceOpAndCopyNamehint().

◆ canonicalizeXorIcmpTrue()

static void canonicalizeXorIcmpTrue	(	XorOp	op,
		unsigned	icmpOperand,
		PatternRewriter &	rewriter
	)

static

Definition at line 1287 of file CombFolds.cpp.

References circt::replaceOpAndCopyNamehint().

◆ combineEqualityICmpWithKnownBitsAndConstant()

static void combineEqualityICmpWithKnownBitsAndConstant	(	ICmpOp	cmpOp,
		const KnownBits &	bitAnalysis,
		const APInt &	rhsCst,
		PatternRewriter &	rewriter
	)

static

Given an equality comparison with a constant value and some operand that has known bits, simplify the comparison to check only the unknown bits of the input.

One simple example of this is that concat(0, stuff) == 0 can be simplified to stuff == 0, or and(x, 3) == 0 can be simplified to extract x[1:0] == 0

Definition at line 2950 of file CombFolds.cpp.

References hw.ConstantOp::create().

◆ combineEqualityICmpWithXorOfConstant()

static void combineEqualityICmpWithXorOfConstant	(	ICmpOp	cmpOp,
		XorOp	xorOp,
		const APInt &	rhs,
		PatternRewriter &	rewriter
	)

static

Definition at line 3034 of file CombFolds.cpp.

References hw.ConstantOp::create().

◆ computeCommonPrefixLength()

template<typename Range >

static size_t computeCommonPrefixLength	(	const Range &	a,
		const Range &	b
	)

static

Definition at line 2823 of file CombFolds.cpp.

Referenced by matchAndRewriteCompareConcat().

◆ constFoldAssociativeOp()

static Attribute constFoldAssociativeOp	(	ArrayRef< Attribute >	operands,
		hw::PEO	paramOpcode
	)

static

Definition at line 691 of file CombFolds.cpp.

References assert().

◆ constFoldBinaryOp()

static Attribute constFoldBinaryOp	(	ArrayRef< Attribute >	operands,
		hw::PEO	paramOpcode
	)

static

Performs constant folding calculate with element-wise behavior on the two attributes in operands and returns the result if possible.

Definition at line 311 of file CombFolds.cpp.

References assert().

Referenced by foldDiv(), and foldMod().

◆ createGenericOp()

static Value createGenericOp	(	Location	loc,
		OperationName	name,
		ArrayRef< Value >	operands,
		OpBuilder &	builder
	)

static

Create a new instance of a generic operation that only has value operands, and has a single result value whose type matches the first operand.

This should not be used to create instances of ops with attributes or with more complicated type signatures.

Definition at line 38 of file CombFolds.cpp.

Referenced by canonicalizeLogicalCstWithConcat(), extractOperandFromFullyAssociative(), and tryFlatteningOperands().

◆ extractConcatToConcatExtract()

static LogicalResult extractConcatToConcatExtract	(	ExtractOp	op,
		ConcatOp	innerCat,
		PatternRewriter &	rewriter
	)

static

Definition at line 475 of file CombFolds.cpp.

References assert(), comb.ExtractOp::create(), and circt::replaceOpAndCopyNamehint().

◆ extractFromReplicate()

static bool extractFromReplicate	(	ExtractOp	op,
		ReplicateOp	replicate,
		PatternRewriter &	rewriter
	)

static

Definition at line 556 of file CombFolds.cpp.

◆ extractOperandFromFullyAssociative()

static Value extractOperandFromFullyAssociative	(	Operation *	fullyAssoc,
		size_t	operandNo,
		PatternRewriter &	rewriter
	)

static

Given a fully associative variadic operation like (a+b+c+d), break the expression into two parts, one without the specified operand (e.g.

tmp = a+b+d) and one that combines that into the full expression (e.g. tmp+c), and return the inner expression.

NOTE: This mutates the operation in place if it only has a single user, which assumes that user will be removed.

Definition at line 2104 of file CombFolds.cpp.

References assert(), createGenericOp(), and circt::replaceOpAndCopyNamehint().

Referenced by foldCommonMuxValue().

◆ foldCommonMuxOperation()

static bool foldCommonMuxOperation	(	MuxOp	mux,
		Operation *	trueOp,
		Operation *	falseOp,
		PatternRewriter &	rewriter
	)

static

This function is invoke when we find a mux with true/false operations that have the same opcode.

Check to see if we can strength reduce the mux by applying it to less data by applying this transformation: mux(cond, op(a, b), op(a, c)) -> op(a, mux(cond, b, c))

Definition at line 2246 of file CombFolds.cpp.

References getConcatOperands(), and circt::replaceOpAndCopyNamehint().

◆ foldCommonMuxValue()

static bool foldCommonMuxValue	(	MuxOp	op,
		bool	isTrueOperand,
		PatternRewriter &	rewriter
	)

static

Fold things like mux(cond, x|y|z|a, a) -> (x|y|z)&replicate(cond)|a and mux(cond, a, x|y|z|a) ->(x|y|z)&replicate(~cond) | a` (when isTrueOperand is true.

Return true on successful transformation, false if not.

These are various forms of "predicated ops" that can be handled with a replicate/and combination.

Definition at line 2145 of file CombFolds.cpp.

References assert(), circt::comb::createOrFoldNot(), and extractOperandFromFullyAssociative().

◆ foldDiv()

template<class Op , bool isSigned>

static OpFoldResult foldDiv	(	Op	op,
		ArrayRef< Attribute >	constants
	)

static

Definition at line 1640 of file CombFolds.cpp.

References constFoldBinaryOp().

◆ foldMod()

template<class Op , bool isSigned>

static OpFoldResult foldMod	(	Op	op,
		ArrayRef< Attribute >	constants
	)

static

Definition at line 1667 of file CombFolds.cpp.

References constFoldBinaryOp(), and getIntAttr().

◆ foldMuxOfUniformArrays()

static bool foldMuxOfUniformArrays	(	MuxOp	op,
		PatternRewriter &	rewriter
	)

static

Definition at line 2341 of file CombFolds.cpp.

◆ getCommonOperand()

template<typename Op >

static Value getCommonOperand ( Op op )

static

Returns a single common operand that all inputs of the operation op can be traced back to, or an empty Value if no such operand exists.

For example for or(a[0], a[1], ..., a[n-1]) this function returns a (assuming the bit-width of a is n).

Definition at line 879 of file CombFolds.cpp.

◆ getConcatOperands()

static void getConcatOperands	(	Value	v,
		SmallVectorImpl< Value > &	result
	)

static

Flatten concat and mux operands into a vector.

Definition at line 52 of file CombFolds.cpp.

References concat(), and getConcatOperands().

Referenced by foldCommonMuxOperation(), getConcatOperands(), and matchAndRewriteCompareConcat().

◆ getIntAttr()

static TypedAttr getIntAttr	(	const APInt &	value,
		MLIRContext *	context
	)

static

Definition at line 46 of file CombFolds.cpp.

◆ getLowestBitAndHighestBitRequired()

static std::pair< size_t, size_t > getLowestBitAndHighestBitRequired	(	Operation *	op,
		bool	narrowTrailingBits,
		size_t	originalOpWidth
	)

static

Definition at line 186 of file CombFolds.cpp.

References assert().

Referenced by narrowOperationWidth().

◆ getMuxChainCondConstant()

static bool getMuxChainCondConstant	(	Value	cond,
		Value	indexValue,
		bool	isInverted,
		std::function< void(hw::ConstantOp)>	constantFn
	)

static

Check to see if the condition to the specified mux is an equality comparison indexValue and one or more constants.

If so, put the constants in the constants vector and return true, otherwise return false.

This is part of foldMuxChain.

Definition at line 1936 of file CombFolds.cpp.

References getMuxChainCondConstant().

Referenced by getMuxChainCondConstant().

◆ getTotalWidth()

static size_t getTotalWidth ( ArrayRef< Value > operands )

static

Definition at line 2837 of file CombFolds.cpp.

References assert().

Referenced by matchAndRewriteCompareConcat().

◆ hasSVAttributes()

static bool hasSVAttributes ( Operation * op )

static

Definition at line 67 of file CombFolds.cpp.

Referenced by findNestedElseIf().

◆ isOpTriviallyRecursive()

static bool isOpTriviallyRecursive ( Operation * op )

static

Definition at line 27 of file CombFolds.cpp.

◆ m_Complement()

template<typename SubType >

static ComplementMatcher< SubType > m_Complement ( const SubType & subExpr )

inlinestatic

Definition at line 84 of file CombFolds.cpp.

◆ matchAndRewriteCompareConcat()

static LogicalResult matchAndRewriteCompareConcat	(	ICmpOp	op,
		Operation *	lhs,
		Operation *	rhs,
		PatternRewriter &	rewriter
	)

static

Reduce the strength icmp(concat(...), concat(...)) by doing a element-wise comparison on common prefix and suffixes.

Returns success() if a rewriting happens. This handles both concat and replicate.

Definition at line 2852 of file CombFolds.cpp.

References applyCmpPredicateToEqualOperands(), assert(), computeCommonPrefixLength(), getConcatOperands(), and getTotalWidth().

◆ narrowOperationWidth()

template<class OpTy >

static bool narrowOperationWidth	(	OpTy	op,
		bool	narrowTrailingBits,
		PatternRewriter &	rewriter
	)

static

Definition at line 217 of file CombFolds.cpp.

References hw.ConstantOp::create(), and getLowestBitAndHighestBitRequired().

◆ shouldBeFlattened()

static bool shouldBeFlattened ( Operation * op )

static

Return true if the op will be flattened afterwards.

Op will be flattend if it has a single user which has a same op type. User must be in same block.

Definition at line 90 of file CombFolds.cpp.

References assert().

Referenced by tryFlatteningOperands().

◆ tryFlatteningOperands()

static bool tryFlatteningOperands	(	Operation *	op,
		PatternRewriter &	rewriter
	)

static

Flattens a single input in op if hasOneUse is true and it can be defined as an Op.

Returns true if successful, and false otherwise.

Example: op(1, 2, op(3, 4), 5) -> op(1, 2, 3, 4, 5) // returns true

Definition at line 108 of file CombFolds.cpp.

References createGenericOp(), circt::replaceOpAndCopyNamehint(), and shouldBeFlattened().

Functions

Function Documentation

◆ applyCmpPredicate()

◆ applyCmpPredicateToEqualOperands()

◆ assumeMuxCondInOperand()

◆ canCombineOppositeBinCmpIntoConstant()

◆ canonicalizeIdempotentInputs()

◆ canonicalizeLogicalCstWithConcat()

◆ canonicalizeXorIcmpTrue()

◆ combineEqualityICmpWithKnownBitsAndConstant()

◆ combineEqualityICmpWithXorOfConstant()

◆ computeCommonPrefixLength()

◆ constFoldAssociativeOp()

◆ constFoldBinaryOp()

◆ createGenericOp()

◆ extractConcatToConcatExtract()

◆ extractFromReplicate()

◆ extractOperandFromFullyAssociative()

◆ foldCommonMuxOperation()

◆ foldCommonMuxValue()

◆ foldDiv()

◆ foldMod()

◆ foldMuxOfUniformArrays()

◆ getCommonOperand()

◆ getConcatOperands()

◆ getIntAttr()

◆ getLowestBitAndHighestBitRequired()

◆ getMuxChainCondConstant()

◆ getTotalWidth()

◆ hasSVAttributes()

◆ isOpTriviallyRecursive()

◆ m_Complement()

◆ matchAndRewriteCompareConcat()

◆ narrowOperationWidth()

◆ shouldBeFlattened()

◆ tryFlatteningOperands()