SIL: don't allow upcast to be done on address types

It's not needed and just complicates the SIL

Author: eeckstein

include/swift/SIL/SILBuilder.h

@@ -1155,6 +1155,7 @@ class SILBuilder {
 
   UpcastInst *createUpcast(SILLocation Loc, SILValue Op, SILType Ty,
                            ValueOwnershipKind forwardingOwnershipKind) {
+    assert(Ty.isObject());
     return insert(UpcastInst::create(getSILDebugLocation(Loc), Op, Ty,
                                      getFunction(), forwardingOwnershipKind));
   }

lib/IRGen/IRGenSIL.cpp

@@ -6813,17 +6813,6 @@ void IRGenSILFunction::visitKeyPathInst(swift::KeyPathInst *I) {
 
 void IRGenSILFunction::visitUpcastInst(swift::UpcastInst *i) {
   auto toTy = getTypeInfo(i->getType()).getSchema()[0].getScalarType();
-
-  // If we have an address, just bitcast, don't explode.
-  if (i->getOperand()->getType().isAddress()) {
-    Address fromAddr = getLoweredAddress(i->getOperand());
-    llvm::Value *toValue = Builder.CreateBitCast(
-      fromAddr.getAddress(), toTy->getPointerTo());
-    Address Addr(toValue, toTy, fromAddr.getAlignment());
-    setLoweredAddress(i, Addr);
-    return;
-  }
-
   Explosion from = getLoweredExplosion(i->getOperand());
   Explosion to;
   assert(from.size() == 1 && "class should explode to single value");

lib/SIL/Verifier/SILVerifier.cpp

@@ -4499,6 +4499,7 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
   void checkUpcastInst(UpcastInst *UI) {
     require(UI->getType() != UI->getOperand()->getType(),
             "can't upcast to same type");
+    require(UI->getType().isObject(), "cannot upcast address types");
     checkNoTrivialToReferenceCast(UI);
     if (UI->getType().is<MetatypeType>()) {
       CanType instTy(UI->getType().castTo<MetatypeType>()->getInstanceType());

lib/SILOptimizer/SILCombiner/SILCombinerCastVisitors.cpp

@@ -484,13 +484,6 @@ SILCombiner::visitUncheckedAddrCastInst(UncheckedAddrCastInst *UADCI) {
     return Builder.createUncheckedAddrCast(UADCI->getLoc(),
                                            OtherUADCI->getOperand(),
                                            UADCI->getType());
-
-  // (unchecked_addr_cast cls->superclass) -> (upcast cls->superclass)
-  if (UADCI->getType() != UADCI->getOperand()->getType() &&
-      UADCI->getType().isExactSuperclassOf(UADCI->getOperand()->getType()))
-    return Builder.createUpcast(UADCI->getLoc(), UADCI->getOperand(),
-                                UADCI->getType());
-
   return nullptr;
 }
 

test/IRGen/upcast.sil

@@ -1194,19 +1194,6 @@ bb0(%0 : $E):
   return %3 : $E
 }
 
-// (load (upcast-addr %x)) -> (upcast-ref (load %x))
-// CHECK-LABEL: sil @load_upcast_addr_to_upcast_ref_load_canonicalization : $@convention(thin) (@inout E) -> B {
-// CHECK: bb0
-// CHECK-NEXT: load
-// CHECK-NEXT: upcast
-// CHECK-NEXT: return
-sil @load_upcast_addr_to_upcast_ref_load_canonicalization : $@convention(thin) (@inout E) -> B {
-bb0(%0 : $*E):
-  %1 = upcast %0 : $*E to $*B
-  %2 = load %1 : $*B
-  return %2 : $B
-}
-
 // CHECK-LABEL: sil @unchecked_enum_data_of_enum : $@convention(thin) () -> Builtin.Int1 {
 // CHECK: bb0
 // CHECK-NEXT: integer_literal

test/SILOptimizer/sil_combine.sil

@@ -1482,38 +1482,6 @@ bb0(%0 : @owned $E):
   return %res : $()
 }
 
-// (load (upcast-addr %x)) -> (upcast-ref (load %x))
-//
-// CHECK-LABEL: sil [ossa] @load_upcast_addr_to_upcast_ref_load_canonicalization : $@convention(thin) (@inout E) -> @owned B {
-// CHECK: bb0
-// CHECK-NEXT: load
-// CHECK-NEXT: upcast
-// CHECK-NEXT: return
-sil [ossa] @load_upcast_addr_to_upcast_ref_load_canonicalization : $@convention(thin) (@inout E) -> @owned B {
-bb0(%0 : $*E):
-  %1 = upcast %0 : $*E to $*B
-  %2 = load [copy] %1 : $*B
-  return %2 : $B
-}
-
-// (load (upcast-addr %x)) -> (upcast-ref (load %x))
-//
-// CHECK-LABEL: sil [ossa] @loadborrow_upcast_addr_to_upcast_ref_load_canonicalization : $@convention(thin) (@inout E) -> @owned B {
-// CHECK: bb0
-// CHECK-NEXT: load_borrow
-// CHECK-NEXT: upcast
-// CHECK-NEXT: copy_value
-// CHECK-NEXT: end_borrow
-// CHECK-NEXT: return
-sil [ossa] @loadborrow_upcast_addr_to_upcast_ref_load_canonicalization : $@convention(thin) (@inout E) -> @owned B {
-bb0(%0 : $*E):
-  %1 = upcast %0 : $*E to $*B
-  %2 = load_borrow %1 : $*B
-  %3 = copy_value %2 : $B
-  end_borrow %2 : $B
-  return %3 : $B
-}
-
 // CHECK-LABEL: sil [ossa] @unchecked_enum_data_of_enum : $@convention(thin) () -> Builtin.Int1 {
 // CHECK: bb0
 // CHECK-NEXT: integer_literal