[Test] Basic tests for DeadEndBlocks.

Author: nate-chandler

lib/SIL/Utils/BasicBlockUtils.cpp

@@ -11,9 +11,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/SIL/BasicBlockUtils.h"
-#include "swift/SIL/BasicBlockDatastructures.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/STLExtras.h"
+#include "swift/SIL/BasicBlockDatastructures.h"
 #include "swift/SIL/Dominance.h"
 #include "swift/SIL/LoopInfo.h"
 #include "swift/SIL/OwnershipUtils.h"
@@ -22,6 +22,7 @@
 #include "swift/SIL/SILBuilder.h"
 #include "swift/SIL/SILFunction.h"
 #include "swift/SIL/TerminatorUtils.h"
+#include "swift/SIL/Test.h"
 #include "llvm/ADT/STLExtras.h"
 
 using namespace swift;
@@ -420,6 +421,27 @@ bool DeadEndBlocks::triviallyEndsInUnreachable(SILBasicBlock *block) {
   return isa<UnreachableInst>(block->getTerminator());
 }
 
+namespace swift::test {
+// Arguments:
+// - none
+// Dumps:
+// - the function
+// - the blocks which are dead-end blocks
+static FunctionTest DeadEndBlocksTest("dead_end_blocks", [](auto &function,
+                                                            auto &arguments,
+                                                            auto &test) {
+  std::unique_ptr<DeadEndBlocks> DeadEnds;
+  DeadEnds.reset(new DeadEndBlocks(&function));
+  function.print(llvm::outs());
+#ifndef NDEBUG
+  for (auto &block : function) {
+    if (DeadEnds->isDeadEnd(&block))
+      block.printID(llvm::outs(), true);
+  }
+#endif
+});
+} // end namespace swift::test
+
 //===----------------------------------------------------------------------===//
 //                  Post Dominance Set Completion Utilities
 //===----------------------------------------------------------------------===//

test/SILOptimizer/dead_end_blocks.sil

@@ -0,0 +1,50 @@
+// RUN: %target-sil-opt -test-runner %s -o /dev/null 2>&1 | %FileCheck %s
+
+// REQUIRES: asserts
+
+// CHECK-LABEL: begin running test {{.*}} on with_trap: dead_end_blocks
+// CHECK-LABEL: sil @with_trap : {{.*}} {
+// CHECK:         cond_br undef, [[DIE:bb[0-9]+]], [[EXIT:bb[0-9]+]]
+// CHECK:       [[DIE]]:
+// CHECK:         unreachable
+// CHECK-LABEL: } // end sil function 'with_trap'
+// CHECK:       [[DIE]]
+// CHECK-LABEL: end running test {{.*}} on with_trap: dead_end_blocks
+sil @with_trap : $@convention(thin) () -> () {
+entry:
+  specify_test "dead_end_blocks"
+  cond_br undef, die, exit
+
+die:
+  unreachable
+
+exit:
+  %retval = tuple ()
+  return %retval : $()
+}
+
+// CHECK-LABEL: begin running test {{.*}} on with_infinite_loop: dead_end_blocks
+// CHECK-LABEL: sil @with_infinite_loop : $@convention(thin) () -> () {
+// CHECK:         cond_br undef, [[EXIT:bb[0-9]+]], [[HEADER:bb[0-9]+]]
+// CHECK:       [[HEADER]]:
+// CHECK:         br [[LOOP:bb[0-9]+]]
+// CHECK:       [[LOOP]]:
+// CHECK:         br [[LOOP]]
+// CHECK-LABEL: } // end sil function 'with_infinite_loop'
+// CHECK:       [[HEADER]]
+// CHECK:       [[LOOP]]
+// CHECK-LABEL: end running test {{.*}} on with_infinite_loop: dead_end_blocks
+sil @with_infinite_loop : $@convention(thin) () -> () {
+entry:
+  specify_test "dead_end_blocks"
+  cond_br undef, exit, header
+header:
+  br loop
+loop:
+  br loop
+exit:
+  %retval = tuple ()
+  return %retval : $()
+}
+
+