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SILCombine: remove dead string.init_empty_with_capacity semantic calls #73388

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Merged
merged 1 commit into from
May 2, 2024
Merged

SILCombine: remove dead string.init_empty_with_capacity semantic calls #73388

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12 changes: 11 additions & 1 deletion lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1448,6 +1448,16 @@ static bool shouldReplaceCallByMetadataConstructor(CanType storageMetaTy) {
return false;
}

static bool canBeRemovedIfResultIsNotUsed(SILFunction *f) {
if (f->getEffectsKind() < EffectsKind::ReleaseNone)
return true;

if (f->hasSemanticsAttr("string.init_empty_with_capacity"))
return true;

return false;
}

SILInstruction *SILCombiner::visitApplyInst(ApplyInst *AI) {
Builder.setCurrentDebugScope(AI->getDebugScope());
// apply{partial_apply(x,y)}(z) -> apply(z,x,y) is triggered
Expand All @@ -1469,7 +1479,7 @@ SILInstruction *SILCombiner::visitApplyInst(ApplyInst *AI) {

// Optimize readonly functions with no meaningful users.
SILFunction *SF = AI->getReferencedFunctionOrNull();
if (SF && SF->getEffectsKind() < EffectsKind::ReleaseNone) {
if (SF && canBeRemovedIfResultIsNotUsed(SF)) {
UserListTy Users;
if (recursivelyCollectARCUsers(Users, AI)) {
if (eraseApply(AI, Users))
Expand Down
12 changes: 12 additions & 0 deletions test/SILOptimizer/string_optimization.swift
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Expand Up @@ -69,6 +69,15 @@ public func testFoldConcat() -> String {
return "a" + "b" + "c"
}

// CHECK-LABEL: sil hidden [noinline] @$s4test0A25InterpolationInLongStringSSyF :
// CHECK-NOT: apply
// CHECK-NOT: bb1
// CHECK: } // end sil function '$s4test0A25InterpolationInLongStringSSyF'
@inline(never)
func testInterpolationInLongString() -> String {
return "\(#function) used in a veeeeeeeeeeeeeeeeeeeery long string"
}

// CHECK-LABEL: sil [noinline] @$s4test0A19UnqualifiedTypeNameSSyF
// CHECK-NOT: apply
// CHECK-NOT: bb1
Expand Down Expand Up @@ -141,6 +150,9 @@ printEmbedded(testFoldStaticLet())
// CHECK-OUTPUT: <abc>
printEmbedded(testFoldConcat())

// CHECK-OUTPUT: <testInterpolationInLongString() used in a veeeeeeeeeeeeeeeeeeeery long string>
printEmbedded(testInterpolationInLongString())

// CHECK-OUTPUT: <Inner>
printEmbedded(testUnqualifiedTypeName())

Expand Down