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[AutoDiff] Fix forward-mode differentiation ownership verification failure. #33898

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Merged
merged 1 commit into from
Sep 11, 2020
Merged

[AutoDiff] Fix forward-mode differentiation ownership verification failure. #33898

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4 changes: 0 additions & 4 deletions lib/SILOptimizer/Differentiation/LinearMapInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -537,10 +537,6 @@ bool LinearMapInfo::shouldDifferentiateInstruction(SILInstruction *inst) {
isa<EndBorrowInst>(inst) || isa<DeallocationInst>(inst) ||
isa<DestroyValueInst>(inst) || isa<DestroyAddrInst>(inst))
return true;
// Should differentiate any instruction that creates an SSA copy of an
// active operand.
if (isa<CopyValueInst>(inst))
return true;
Comment on lines -540 to -543
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Note: I tried to track down the origin of this code. I found it was added by this commit, though it existed in a different form prior to the commit.

I think this special-case for copy_value was just an oversight/latent error.

}
return false;
}
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11 changes: 11 additions & 0 deletions test/AutoDiff/validation-test/forward_mode_simple.swift
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Expand Up @@ -1389,4 +1389,15 @@ ForwardModeTests.test("ApplyNonActiveIndirectResult") {
expectEqual(1.0, derivative(at: 2, in: applyNonactiveArgumentActiveIndirectResult))
}

ForwardModeTests.test("SR-13530") {
// SR-13530: Test "leaked owned value" ownership verification failure related
// to differential generation for `copy_value` instruction.
@differentiable
func SR_13530(_ x: NonresilientTracked<Float>) -> NonresilientTracked<Float> {
precondition(x >= 0)
return x
}
expectEqual(1, derivative(at: 2, in: SR_13530))
}

runAllTests()