Merge pull request #69276 from nate-chandler/opaque-values/20231019/1/fix-move-skipping

[AddressLowering] Move into secondary use.

Author: nate-chandler

lib/SILOptimizer/Mandatory/AddressLowering.cpp

@@ -451,12 +451,12 @@ void ValueStorageMap::ValueStoragePair::dump() const {
     llvm::dbgs() << "UNKNOWN!\n";
   storage.dump();
 }
-void ValueStorageMap::dumpProjections(SILValue value) {
+void ValueStorageMap::dumpProjections(SILValue value) const {
   for (auto *pair : getProjections(value)) {
     pair->dump();
   }
 }
-void ValueStorageMap::dump() {
+void ValueStorageMap::dump() const {
   llvm::dbgs() << "ValueStorageMap:\n";
   for (unsigned ordinal : indices(valueVector)) {
     auto &valStoragePair = valueVector[ordinal];
@@ -1747,8 +1747,16 @@ void AddressMaterialization::initializeComposingUse(Operand *operand) {
     ValueStorage &storage = pass.valueStorageMap.getStorage(def);
     assert(storage.isRewritten && "Source value should be rewritten");
 
-    if (storage.isUseProjection)
-      return;
+    // If the operand projects into one of its users and this user is that one
+    // into which it projects, then the memory was already initialized.  If it's
+    // another user, however, that memory is _not_initialized.
+    if (storage.isUseProjection) {
+      auto *aggregate = dyn_cast<SingleValueInstruction>(operand->getUser());
+      if (aggregate && (storage.projectedStorageID ==
+                        pass.valueStorageMap.getOrdinal(aggregate))) {
+        return;
+      }
+    }
 
     auto destAddr =
         materializeProjectionIntoUse(operand, /*intoPhiOperand*/ false);

lib/SILOptimizer/Mandatory/AddressLowering.h

@@ -396,8 +396,8 @@ class ValueStorageMap {
   bool isComposingUseProjection(Operand *oper) const;
 
 #ifndef NDEBUG
-  void dumpProjections(SILValue value);
-  void dump();
+  void dumpProjections(SILValue value) const;
+  void dump() const;
 #endif
 };
 

test/SILOptimizer/address_lowering.sil

@@ -60,6 +60,10 @@ struct Pair<T> {
   var y : T
 }
 
+struct Box<T> {
+  var t: T
+}
+
 struct Box2<T, U> {
     var v1: T
     var v2: U
@@ -2712,6 +2716,44 @@ entry:
   return %retval : $()
 }
 
+// CHECK-LABEL: sil [ossa] @test_struct_1_two_use_projections : {{.*}} {
+// CHECK:         [[S_ADDR:%[^,]+]] = alloc_stack $Box<T>                        
+// CHECK:         [[S2_ADDR:%[^,]+]] = alloc_stack $Box<T>                        
+// CHECK:         [[S_FIELD_ADDR:%[^,]+]] = struct_element_addr [[S_ADDR]] : $*Box<T>, #Box.t  
+// CHECK:         apply undef<T>([[S_FIELD_ADDR]])
+// CHECK:         cond_br undef, [[LEFT:bb[0-9]+]], [[RIGHT:bb[0-9]+]]                         
+// CHECK:       [[RIGHT]]:                                              
+// CHECK:         destroy_addr [[S_ADDR]] : $*Box<T>                      
+// CHECK:         br [[EXIT:bb[0-9]+]]                                          
+// CHECK:       [[LEFT]]:                                              
+// CHECK:         [[S2_FIELD_ADDR:%[^,]+]] = struct_element_addr [[S2_ADDR]] : $*Box<T>, #Box.t  
+// CHECK:         copy_addr [take] [[S_FIELD_ADDR]] to [init] [[S2_FIELD_ADDR]]
+// CHECK:         destroy_addr [[S2_ADDR]] : $*Box<T>                      
+// CHECK:         br [[EXIT]]                                          
+// CHECK:       [[EXIT]]:                                              
+// CHECK:         dealloc_stack [[S2_ADDR]] : $*Box<T>                     
+// CHECK:         dealloc_stack [[S_ADDR]] : $*Box<T>                     
+// CHECK-LABEL: } // end sil function 'test_struct_1_two_use_projections'
+sil [ossa] @test_struct_1_two_use_projections : $@convention(thin) <T> () -> () {
+entry:
+  %box = apply undef<T>() : $@convention(thin) <T> () -> (@out T)
+  cond_br undef, left, right
+
+left:
+  %s2 = struct $Box<T>(%box : $T)
+  destroy_value %s2 : $Box<T>
+  br exit
+
+right:
+  %s = struct $Box<T>(%box : $T)
+  destroy_value %s : $Box<T>
+  br exit
+
+exit:
+  %retval = tuple ()
+  return %retval : $()
+}
+
 // CHECK-LABEL: sil [ossa] @test_tuple_pack_extract : {{.*}} {
 // CHECK:       bb0([[TUPLE_PACK_ADDR:%[^,]+]] :
 // CHECK:         [[INDEX:%[^,]+]] = dynamic_pack_index