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Bailout from an illegal transformation in semantic arc opts #83052

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Merged
merged 1 commit into from
Jul 15, 2025
Merged

Bailout from an illegal transformation in semantic arc opts #83052

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10 changes: 9 additions & 1 deletion lib/SILOptimizer/SemanticARC/CopyValueOpts.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -503,6 +503,13 @@ static bool tryJoinIfDestroyConsumingUseInSameBlock(
if (visitedInsts.count(use->getUser()))
return false;

// If the cvi's operand value has a non-consuming use in the same
// instruction which consumes the copy, bailout. NOTE:
// isUseBetweenInstAndBlockEnd does not check this.
if (user == singleCVIConsumingUse->getUser()) {
return false;
}

// Ok, we have a use that isn't in our visitedInsts region. That being said,
// we may still have a use that introduces a new BorrowScope onto our
// copy_value's operand that overlaps with our forwarding value region. In
Expand All @@ -513,14 +520,15 @@ static bool tryJoinIfDestroyConsumingUseInSameBlock(
// we need to only find scopes that end within the region in between the
// singleConsumingUse (the original forwarded use) and the destroy_value. In
// such a case, we must bail!
if (auto operand = BorrowingOperand(use))
if (auto operand = BorrowingOperand(use)) {
if (!operand.visitScopeEndingUses([&](Operand *endScopeUse) {
// Return false if we did see the relevant end scope instruction
// in the block. That means that we are going to exit early and
// return false.
return !visitedInsts.count(endScopeUse->getUser());
}))
return false;
}
}

// Ok, we now know that we can eliminate this value.
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39 changes: 39 additions & 0 deletions test/SILOptimizer/semantic-arc-opts-lifetime-joining.sil
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Expand Up @@ -975,3 +975,42 @@ bb0:
return %r : $()
}

sil @consume_and_borrow : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
sil @borrow : $@convention(thin) (@guaranteed Klass) -> ()
sil @consume : $@convention(thin) (@owned Klass) -> ()
sil @get_klass : $@convention(thin) () -> @owned Klass

// CHECK-LABEL: sil hidden [ossa] @borrow_and_consume_copyable_test1 :
// CHECK-NOT: copy_value
// CHECK-LABEL: } // end sil function 'borrow_and_consume_copyable_test1'
sil hidden [ossa] @borrow_and_consume_copyable_test1 : $@convention(thin) () -> () {
bb0:
%0 = function_ref @get_klass : $@convention(thin) () -> @owned Klass
%1 = apply %0() : $@convention(thin) () -> @owned Klass
%2 = move_value [var_decl] %1
%3 = copy_value %2
%4 = function_ref @borrow : $@convention(thin) (@guaranteed Klass) -> ()
%5 = apply %4(%2) : $@convention(thin) (@guaranteed Klass) -> ()
%6 = function_ref @consume : $@convention(thin) (@owned Klass) -> ()
%7 = apply %6(%3) : $@convention(thin) (@owned Klass) -> ()
destroy_value %2
%9 = tuple ()
return %9
}

// CHECK-LABEL: sil hidden [ossa] @borrow_and_consume_copyable_test2 :
// CHECK: copy_value
// CHECK-LABEL: } // end sil function 'borrow_and_consume_copyable_test2'
sil hidden [ossa] @borrow_and_consume_copyable_test2 : $@convention(thin) () -> () {
bb0:
%0 = function_ref @get_klass : $@convention(thin) () -> @owned Klass
%1 = apply %0() : $@convention(thin) () -> @owned Klass
%2 = move_value [var_decl] %1
%3 = copy_value %2
%4 = function_ref @consume_and_borrow : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
%5 = apply %4(%3, %2) : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
destroy_value %2
%7 = tuple ()
return %7
}