COWArrayOpt: ensure that we can hoist all address projections that we…

… stripped. This change is needed because we new consider index_addr as address projection in Projection.h
pyrtsa · Jan 27, 2016 · 905fd37 · 905fd37
1 parent ae28353
commit 905fd37
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Showing 4 changed files with 46 additions and 6 deletions.
diff --git a/include/swift/SIL/InstructionUtils.h b/include/swift/SIL/InstructionUtils.h
@@ -35,13 +35,14 @@ SILValue stripUpCasts(SILValue V);
 /// upcasts and downcasts.
 SILValue stripClassCasts(SILValue V);
 
-/// Return the underlying SILValue after stripping off all casts and
-/// address projection instructions.
-///
-/// An address projection instruction is one of one of ref_element_addr,
-/// struct_element_addr, tuple_element_addr.
+/// Return the underlying SILValue after stripping off all address projection
+/// instructions.
 SILValue stripAddressProjections(SILValue V);
 
+/// Return the underlying SILValue after stripping off all address projection
+/// instructions which have a single operand.
+SILValue stripUnaryAddressProjections(SILValue V);
+
 /// Return the underlying SILValue after stripping off all aggregate projection
 /// instructions.
 ///

diff --git a/lib/SIL/InstructionUtils.cpp b/lib/SIL/InstructionUtils.cpp
@@ -141,6 +141,18 @@ SILValue swift::stripAddressProjections(SILValue V) {
   }
 }
 
+SILValue swift::stripUnaryAddressProjections(SILValue V) {
+  while (true) {
+    V = stripSinglePredecessorArgs(V);
+    if (!NewProjection::isAddressProjection(V))
+      return V;
+    auto *Inst = cast<SILInstruction>(V);
+    if (Inst->getNumOperands() > 1)
+      return V;
+    V = Inst->getOperand(0);
+  }
+}
+
 SILValue swift::stripValueProjections(SILValue V) {
   while (true) {
     V = stripSinglePredecessorArgs(V);

diff --git a/lib/SILOptimizer/LoopTransforms/COWArrayOpt.cpp b/lib/SILOptimizer/LoopTransforms/COWArrayOpt.cpp
@@ -1433,7 +1433,7 @@ bool COWArrayOpt::hoistMakeMutable(ArraySemanticsCall MakeMutable) {
 
   // We can hoist address projections (even if they are only conditionally
   // executed).
-  auto ArrayAddrBase = stripAddressProjections(CurrentArrayAddr);
+  auto ArrayAddrBase = stripUnaryAddressProjections(CurrentArrayAddr);
   SILBasicBlock *ArrayAddrBaseBB = ArrayAddrBase->getParentBB();
 
   if (ArrayAddrBaseBB && !DomTree->dominates(ArrayAddrBaseBB, Preheader)) {

diff --git a/test/SILOptimizer/cowarray_opt.sil b/test/SILOptimizer/cowarray_opt.sil
@@ -1051,6 +1051,33 @@ bb2:
   return %7 : $()
 }
 
+// We don't support hoisting non-unary projections yet.
+
+// CHECK-LABEL: sil @dont_hoist_non_unary_projections
+// CHECK-NOT: index_addr
+// CHECK: bb2({{.*}}):
+// CHECK: index_addr
+sil @dont_hoist_non_unary_projections : $@convention(thin) (@inout ContainerContainer, @inout Builtin.Int1) -> () {
+bb0(%0 : $*ContainerContainer, %1 : $*Builtin.Int1):
+  br bb1
+
+bb1:
+  %2 = struct_element_addr %0 : $*ContainerContainer, #ContainerContainer.container
+  br bb2(%2 : $*Container)
+
+bb2(%3: $*Container):
+  %i = integer_literal $Builtin.Int32, 0
+  %3i = index_addr %3 : $*Container, %i : $Builtin.Int32
+  %4 = struct_element_addr %3i : $*Container, #Container.array
+  %5 = function_ref @array_make_mutable : $@convention(method) (@inout MyArray<MyStruct>) -> ()
+  %6 = apply %5(%4) : $@convention(method) (@inout MyArray<MyStruct>) -> ()
+  cond_br undef, bb1, bb3
+
+bb3:
+  %7 = tuple()
+  return %7 : $()
+}
+
 // CHECK-LABEL: sil @hoist_projections2
 // CHECK: bb0([[CONTAINER:%[0-9]+]]
 // CHECK: [[CONTAINER2:%.*]] = struct_element_addr [[CONTAINER]] : $*ContainerContainer