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SwiftCompilerSources/SIL: More robust IntegerLiteralInst construction

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ac619010e3 backfired when building the
stdlib on rebranch. This time the problem is reversed: we should be
interpreting an integer as unsigned where we no longer do, here:
8f7af45115/SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyLoad.swift (L78).

Rather than treating integers as signed by default, make
`Builder.createIntegerLiteral` accept a generic `FixedWidthInteger`, and
manipulate the value based on the generic type argument's signedness.

This doesn't entirely define away unintentional sign extensions, but
makes this mistake of humouring the parameter type less likely.
This commit is contained in:
Anthony Latsis
2025-09-25 04:15:20 +01:00
parent 8f7af45115
commit 3d898f71e5
2 changed files with 28 additions and 9 deletions
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2
SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyLoad.swift
View File

@@ -75,7 +75,7 @@ extension LoadInst : OnoneSimplifiable, SILCombineSimplifiable {
index < stringLiteral.value.count {
let builder = Builder(before: self, context)
let charLiteral = builder.createIntegerLiteral(Int(stringLiteral.value[index]), type: type)
let charLiteral = builder.createIntegerLiteral(stringLiteral.value[index], type: type)
uses.replaceAll(with: charLiteral, context)
context.erase(instruction: self)
return true

35
SwiftCompilerSources/Sources/SIL/Builder.swift
View File

@@ -190,19 +190,38 @@ public struct Builder {
}
}
private func createIntegerLiteral(_ value: Int, type: Type, treatAsSigned: Bool) -> IntegerLiteralInst {
let literal = bridged.createIntegerLiteral(type.bridged, value, treatAsSigned)
/// Creates a integer literal instruction with the given integer value and
/// type. If an extension is necessary, the value is extended in accordance
/// with the signedness of `Value`.
public func createIntegerLiteral<Value: FixedWidthInteger>(
_ value: Value,
type: Type
) -> IntegerLiteralInst {
precondition(
Value.bitWidth <= Int.bitWidth,
"Cannot fit \(Value.bitWidth)-bit integer into \(Int.bitWidth)-bit 'Swift.Int'"
)
// Extend the value based on its signedness to the bit width of `Int` and
// reinterpret it as an `Int`.
let extendedValue: Int =
if Value.isSigned {
Int(value)
} else {
// NB: This initializer is effectively a generic equivalent
// of `Int(bitPattern:)`
Int(truncatingIfNeeded: value)
}
let literal = bridged.createIntegerLiteral(type.bridged, extendedValue, Value.isSigned)
return notifyNew(literal.getAs(IntegerLiteralInst.self))
}
public func createIntegerLiteral(_ value: Int, type: Type) -> IntegerLiteralInst {
createIntegerLiteral(value, type: type, treatAsSigned: true)
}
/// Creates a `Builtin.Int1` integer literal instruction with the given value.
/// Creates a `Builtin.Int1` integer literal instruction with a value
/// corresponding to the given Boolean.
public func createBoolLiteral(_ value: Bool) -> IntegerLiteralInst {
let boolType = notificationHandler.getBuiltinIntegerType(1).type
return createIntegerLiteral(value ? 1 : 0, type: boolType, treatAsSigned: false)
let integerValue: UInt = value ? 1 : 0
return createIntegerLiteral(integerValue, type: boolType)
}
public func createAllocRef(_ type: Type, isObjC: Bool = false, canAllocOnStack: Bool = false, isBare: Bool = false,