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Fix MandatoryARCOpts tryJoiningCopyValueLiveRangeWithOperand. #64836

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Merged
atrick merged 1 commit into from
Apr 3, 2023
Merged

Fix MandatoryARCOpts tryJoiningCopyValueLiveRangeWithOperand. #64836

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6 changes: 6 additions & 0 deletions lib/SILOptimizer/SemanticARC/CopyValueOpts.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -493,6 +493,12 @@ static bool tryJoinIfDestroyConsumingUseInSameBlock(
}))
return false;
}
// Check whether the uses considered immediately above are all effectively
// instantaneous uses. Pointer escapes propagate values ways that may not be
// discoverable.
if (hasPointerEscape(operand)) {
return false;
}

// Ok, we now know that we can eliminate this value.
LLVM_DEBUG(llvm::dbgs()
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39 changes: 38 additions & 1 deletion test/SILOptimizer/semantic-arc-opts-lifetime-joining.sil
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@@ -1,5 +1,4 @@
// RUN: %target-sil-opt -module-name Swift -enable-sil-verify-all -semantic-arc-opts -sil-semantic-arc-peepholes-lifetime-joining %s | %FileCheck %s
// REQUIRES: swift_stdlib_asserts

// NOTE: Some of our tests here depend on borrow elimination /not/ running!
// Please do not add it to clean up the IR like we did in
Expand All @@ -15,6 +14,13 @@ import Builtin

typealias AnyObject = Builtin.AnyObject

struct Bool {
var value : Builtin.Int1
}

sil @closureCapturesBool : $@convention(thin) (@guaranteed { var Bool }) -> ()
sil @closureArgumentEscapes : $@convention(thin) (@owned @callee_guaranteed () -> ()) -> ()

enum MyNever {}
enum FakeOptional<T> {
case none
Expand Down Expand Up @@ -883,3 +889,34 @@ bb3(%result : @owned $FakeOptional<Builtin.NativeObject>):
dealloc_stack %allocStack : $*Builtin.NativeObject
return %result : $FakeOptional<Builtin.NativeObject>
}

// Don't do this optimization:
// Eliminate borrowed copy with useless lifetime:
// %5 = copy_value %0 : ${ var Bool }
//
// CHECK: sil hidden [ossa] @testCapturedSingleDestroyCopy : $@convention(thin) () -> Bool {
// CHECK: load [trivial] %{{.*}} : $*Bool
// CHECK: destroy_value %0 : ${ var Bool }
sil hidden [ossa] @testCapturedSingleDestroyCopy : $@convention(thin) () -> Bool {
bb0:
// var test = false
%0 = alloc_box ${ var Bool }, var, name "test"
%1 = project_box %0 : ${ var Bool }, 0
%2 = integer_literal $Builtin.Int1, 0
%3 = struct $Bool (%2 : $Builtin.Int1)
store %3 to [trivial] %1 : $*Bool

// capture test in an escaping closure
%5 = copy_value %0 : ${ var Bool }
%6 = function_ref @closureCapturesBool : $@convention(thin) (@guaranteed { var Bool }) -> ()
%7 = partial_apply [callee_guaranteed] %6(%5) : $@convention(thin) (@guaranteed { var Bool }) -> ()
%8 = function_ref @closureArgumentEscapes : $@convention(thin) (@owned @callee_guaranteed () -> ()) -> ()
%9 = apply %8(%7) : $@convention(thin) (@owned @callee_guaranteed () -> ()) -> ()

// return test
%10 = begin_access [read] [dynamic] %1 : $*Bool
%11 = load [trivial] %10 : $*Bool
end_access %10 : $*Bool
destroy_value %0 : ${ var Bool }
return %11 : $Bool
}