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Fix licm not projecting load path before load splitting. #84173

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Merged
merged 1 commit into from
Sep 9, 2025
Merged

Fix licm not projecting load path before load splitting. #84173

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3 changes: 2 additions & 1 deletion SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LoopInvariantCodeMotion.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -587,7 +587,8 @@ private extension AnalyzedInstructions {
continue
}

guard let splitLoads = loadInst.trySplit(alongPath: accessPath.projectionPath, context) else {
guard let projectionPath = loadInst.operand.value.accessPath.getProjection(to: accessPath),
let splitLoads = loadInst.trySplit(alongPath: projectionPath, context) else {
newLoads.push(loadInst)
return false
}
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41 changes: 41 additions & 0 deletions test/SILOptimizer/licm.sil
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Original file line number Diff line number Diff line change
Expand Up @@ -1514,6 +1514,47 @@ bb2:
return %r1 : $()
}

struct Outer {
var interactions: Inner
}

public struct Inner {
public let x: Int
var storage: ContiguousArray<Double>
}

sil @$get_array_from_inner : $@convention(method) (Inner) -> (ContiguousArray<Double>)

// Make sure we project load access path to matching store access path.
// Otherwise the pass could crash.
//
// CHECK-LABEL: sil @project_load_path_before_splitting_crash :
// CHECK: load
// CHECK: bb1(%8 : $ContiguousArray<Double>):
// CHECK: bb3:
// CHECK: store
// CHECK: } // end sil function 'project_load_path_before_splitting_crash'
sil @project_load_path_before_splitting_crash : $@convention(thin) (@inout Outer) -> () {
bb0(%0 : $*Outer):
%1 = struct_element_addr %0, #Outer.interactions
%2 = struct_element_addr %1, #Inner.storage
br bb1

bb1:
%4 = load %1
%5 = function_ref @$get_array_from_inner : $@convention(method) (Inner) -> ContiguousArray<Double>
%6 = apply %5(%4) : $@convention(method) (Inner) -> ContiguousArray<Double>
store %6 to %2
cond_br undef, bb2, bb3

bb2:
br bb1

bb3:
%10 = tuple ()
return %10
}

// CHECK-LABEL: sil @dont_hoist_builtin_once_memory_conflict :
// CHECK: function_ref
// CHECK: br bb1
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