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DeadAllocElimination: fix a bug when promoting mark_dependence instructions #84662

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Merged
merged 1 commit into from
Oct 4, 2025
Merged

DeadAllocElimination: fix a bug when promoting mark_dependence instructions #84662

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2 changes: 1 addition & 1 deletion lib/SILOptimizer/Mandatory/PredictableMemOpt.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2339,7 +2339,7 @@ SILValue OptimizeDeadAlloc::promoteMarkDepBase(
}
LLVM_DEBUG(llvm::dbgs() << " To value: " << dependentValue);
md->replaceAllUsesWith(dependentValue);
deleter.deleteIfDead(md);
deleter.forceDelete(md);
return dependentValue;
}

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25 changes: 25 additions & 0 deletions test/SILOptimizer/mandatory_performance_optimizations.sil
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,10 @@ import Builtin
import Swift
import SwiftShims

struct NonTrivialStruct {
var s: String
}

sil_global [let] @g1 : $Int32
sil_global [let] @g2 : $Int32

Expand Down Expand Up @@ -203,6 +207,27 @@ bb3:
return %1 : $Int32
}

sil @createNonTrivialStruct : $@convention(thin) (Int) -> @owned NonTrivialStruct

// CHECK-LABEL: sil [no_allocation] [perf_constraint] [ossa] @test_dead_alloc_elimination_with_mark_dependence :
// CHECK-NOT: alloc_stack
// CHECK: } // end sil function 'test_dead_alloc_elimination_with_mark_dependence'
sil [ossa] [no_allocation] @test_dead_alloc_elimination_with_mark_dependence : $@convention(thin) (Int) -> () {
bb0(%0 : $Int):
%1 = alloc_stack [lexical] $Int
store %0 to [trivial] %1
%4 = load [trivial] %1
%5 = function_ref @createNonTrivialStruct : $@convention(thin) (Int) -> @owned NonTrivialStruct
%6 = apply %5(%4) : $@convention(thin) (Int) -> @owned NonTrivialStruct
%7 = mark_dependence [nonescaping] %6 on %1
%9 = mark_dependence [nonescaping] %7 on %1
%10 = destructure_struct %9
destroy_value %10
%12 = tuple ()
dealloc_stack %1
return %12
}

// CHECK-LABEL: sil [no_locks] [perf_constraint] [ossa] @remove_metatype_arg :
// CHECK: [[F:%.*]] = function_ref @$s12metatype_argTf4ndn_n : $@convention(thin) (Int, @owned Builtin.NativeObject) -> @owned Builtin.NativeObject
// CHECK: [[A:%.*]] = apply [[F]](%0, %1) : $@convention(thin) (Int, @owned Builtin.NativeObject) -> @owned Builtin.NativeObject
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