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0509a056fb
Make filter APIs for UseList chainable by adding them to Sequence where Element == Operand For example, it allows to write: ``` let singleUse = value.uses.ignoreDebugUses.ignoreUsers(ofType: EndAccessInst.self).singleUse ``` Also, add `UseList.getSingleUser(notOfType:)`
106 lines
3.7 KiB
Swift
106 lines
3.7 KiB
Swift
//===--- SimplifyDestructure.swift ----------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import SIL
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extension DestructureTupleInst : OnoneSimplifyable {
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func simplify(_ context: SimplifyContext) {
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// Eliminate the redundant instruction pair
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// ```
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// %t = tuple (%0, %1, %2)
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// (%3, %4, %5) = destructure_tuple %t
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// ```
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// and replace the results %3, %4, %5 with %0, %1, %2, respectively
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//
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if let tuple = self.tuple as? TupleInst {
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tryReplaceConstructDestructPair(construct: tuple, destruct: self, context)
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}
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}
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}
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extension DestructureStructInst : OnoneSimplifyable {
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func simplify(_ context: SimplifyContext) {
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switch self.struct {
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case let str as StructInst:
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// Eliminate the redundant instruction pair
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// ```
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// %s = struct (%0, %1, %2)
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// (%3, %4, %5) = destructure_struct %s
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// ```
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// and replace the results %3, %4, %5 with %0, %1, %2, respectively
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//
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tryReplaceConstructDestructPair(construct: str, destruct: self, context)
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case let copy as CopyValueInst:
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// Similar to the pattern above, but with a copy_value:
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// Replace
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// ```
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// %s = struct (%0, %1, %2)
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// %c = copy_value %s // can also be a chain of multiple copies
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// (%3, %4, %5) = destructure_struct %c
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// ```
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// with
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// ```
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// %c0 = copy_value %0
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// %c1 = copy_value %1
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// %c2 = copy_value %2
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// %s = struct (%0, %1, %2) // keep the original struct
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// ```
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// and replace the results %3, %4, %5 with %c0, %c1, %c2, respectively.
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//
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// This transformation has the advantage that we can do it even if the `struct` instruction
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// has other uses than the `copy_value`.
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//
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if copy.uses.singleUse?.instruction == self,
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let structInst = copy.fromValue.lookThroughCopy as? StructInst,
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structInst.parentBlock == self.parentBlock
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{
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for (result, operand) in zip(self.results, structInst.operands) {
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if operand.value.type.isTrivial(in: parentFunction) {
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result.uses.replaceAll(with: operand.value, context)
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} else {
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let builder = Builder(before: structInst, context)
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let copiedOperand = builder.createCopyValue(operand: operand.value)
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result.uses.replaceAll(with: copiedOperand, context)
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}
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}
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context.erase(instruction: self)
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context.erase(instruction: copy)
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}
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default:
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break
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}
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}
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}
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private func tryReplaceConstructDestructPair(construct: SingleValueInstruction,
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destruct: MultipleValueInstruction,
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_ context: SimplifyContext) {
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let singleUse = context.preserveDebugInfo ? construct.uses.singleUse : construct.uses.ignoreDebugUses.singleUse
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let canEraseFirst = singleUse?.instruction == destruct
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if !canEraseFirst && construct.parentFunction.hasOwnership && construct.ownership == .owned {
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// We cannot add more uses to this tuple without inserting a copy.
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return
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}
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for (result, operand) in zip(destruct.results, construct.operands) {
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result.uses.replaceAll(with: operand.value, context)
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}
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if canEraseFirst {
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context.erase(instructionIncludingDebugUses: destruct)
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}
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}
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