Merge pull request swiftlang#82668 from eeckstein/revert-abts

Optimizer: revert to legacy alloc-box-to-stack optimization

Author: eeckstein

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -116,12 +116,13 @@ static void addMandatoryDiagnosticOptPipeline(SILPassPipelinePlan &P) {
   // Select access kind after capture promotion and before stack promotion.
   // This guarantees that stack-promotable boxes have [static] enforcement.
   P.addAccessEnforcementSelection();
-
+/* Temporarily disabled: rdar://154686063, rdar://154713388
 #ifdef SWIFT_ENABLE_SWIFT_IN_SWIFT
   P.addMandatoryAllocBoxToStack();
 #else
+*/
   P.addLegacyAllocBoxToStack();
-#endif
+//#endif
   P.addNoReturnFolding();
   P.addBooleanLiteralFolding();
   addDefiniteInitialization(P);
@@ -417,7 +418,8 @@ void addHighLevelLoopOptPasses(SILPassPipelinePlan &P) {
 void addFunctionPasses(SILPassPipelinePlan &P,
                        OptimizationLevelKind OpLevel) {
   // Promote box allocations to stack allocations.
-  P.addAllocBoxToStack();
+  // TODO: change this to add addAllocBoxToStack once rdar://154686063, rdar://154713388 is fixed
+  P.addLegacyAllocBoxToStack();
 
   if (P.getOptions().DestroyHoisting == DestroyHoistingOption::On) {
     P.addDestroyAddrHoisting();

test/IRGen/generic_tuples.swift

@@ -27,10 +27,9 @@ func dup<T>(_ x: T) -> (T, T) { var x = x; return (x,x) }
 //   Copy 'x' into the first result.
 // CHECK-NEXT: call ptr [[WITNESS]](ptr noalias %0, ptr noalias [[X_ALLOCA]], ptr %T)
 //   Copy 'x' into the second element.
+// CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[VWT]], i32 4
+// CHECK-NEXT: [[WITNESS:%.*]] = load ptr, ptr [[WITNESS_ADDR]], align 8
 // CHECK-NEXT: call ptr [[WITNESS]](ptr noalias %1, ptr noalias [[X_ALLOCA]], ptr %T)
-// CHECK-NEXT: [[WITNESS_ADDR:%.*]] = getelementptr inbounds ptr, ptr [[VWT]], i32 1
-// CHECK-NEXT: [[DESTROYWITNESS:%.*]] = load ptr, ptr [[WITNESS_ADDR]], align 8
-// CHECK-NEXT: call void [[DESTROYWITNESS]](ptr noalias [[X_ALLOCA]],
 
 struct S {}
 

test/SILOptimizer/allocboxtostack_localapply.swift

@@ -103,7 +103,7 @@ public func testboxescapes() -> (() -> ()) {
 }
 
 // CHECK-LABEL: sil [noinline] @$s26allocboxtostack_localapply9testrecurSiyF :
-// CHECK:          alloc_stack [var_decl] $Int, var, name "x"
+// CHECK: alloc_box ${ var Int }, var, name "x"
 // CHECK-LABEL: } // end sil function '$s26allocboxtostack_localapply9testrecurSiyF'
 @inline(never)
 public func testrecur() -> Int {
@@ -146,9 +146,14 @@ public func testdfs1() -> Int {
   return common()
 }
 
+// Test to make sure we don't optimize the case when we have an inner common function call for multiple boxes.
+// We don't optimize this case now, because we don't have additional logic to correctly construct AppliesToSpecialize
+// Order of function calls constructed in PromotedOperands: bar innercommon local1 bas innercommon local2
+// AppliesToSpecialize should have the order: bar bas innercommon local1 local2
+// Since we don't maintain any tree like data structure with more info on the call tree, this is not possible to construct today 
 // CHECK-LABEL: sil [noinline] @$s26allocboxtostack_localapply8testdfs2SiyF :
-// CHECK:          alloc_stack [var_decl] $Int, var, name "x"
-// CHECK:          alloc_stack [var_decl] $Int, var, name "y"
+// CHECK: alloc_box ${ var Int }, var, name "x"
+// CHECK: alloc_box ${ var Int }, var, name "y"
 // CHECK-LABEL:} // end sil function '$s26allocboxtostack_localapply8testdfs2SiyF'
 @inline(never)
 public func testdfs2() -> Int {
@@ -177,20 +182,3 @@ public func testdfs2() -> Int {
   return local1() + local2()
 }
 
-// CHECK-LABEL: sil @$s26allocboxtostack_localapply15call2localfuncsSiyF :
-// CHECK-NOT:     alloc_box
-// CHECK-LABEL:} // end sil function '$s26allocboxtostack_localapply15call2localfuncsSiyF'
-public func call2localfuncs() -> Int {
-    var a1 = 1
-    
-    @inline(never)
-    func innerFunction() {
-        a1 += 1
-    }
-
-    innerFunction()
-    innerFunction()
-
-    return a1
-}
-

test/SILOptimizer/definite_init_protocol_init.swift

@@ -99,8 +99,7 @@ struct AddressOnlyStruct : TriviallyConstructible {
 // CHECK-NEXT: apply [[FN]]<AddressOnlyStruct>([[SELF_BOX]], %1, [[METATYPE]])
 // CHECK-NEXT: copy_addr [take] [[SELF_BOX]] to [init] [[SELF]]
 // CHECK-NEXT: dealloc_stack [[SELF_BOX]]
-// CHECK-NEXT: copy_addr [[SELF]] to [init] %0
-// CHECK-NEXT: destroy_addr [[SELF]]
+// CHECK-NEXT: copy_addr [take] [[SELF]] to [init] %0
 // CHECK-NEXT: dealloc_stack [[SELF]]
 // CHECK-NEXT: [[RESULT:%.*]] = tuple ()
 // CHECK-NEXT: return [[RESULT]]