[gardening] Use const_cast rather than implement SILBasicBlock::getSingleSuccessor() twice for const/non-const.

gottesmm · gottesmm · commit 529eec30b766 · 2016-11-27T11:58:20.000-08:00
diff --git a/include/swift/SIL/SILBasicBlock.h b/include/swift/SIL/SILBasicBlock.h
@@ -216,9 +216,7 @@ public llvm::ilist_node<SILBasicBlock>, public SILAllocated<SILBasicBlock> {
   }
 
   const SILBasicBlock *getSingleSuccessor() const {
-    if (succ_empty() || std::next(succ_begin()) != succ_end())
-      return nullptr;
-    return *succ_begin();
+    return const_cast<SILBasicBlock *>(this)->getSingleSuccessor();
   }
 
   /// \brief Returns true if \p BB is a successor of this block.

Original file line number	Diff line number	Diff line change
`@@ -216,9 +216,7 @@ public llvm::ilist_node<SILBasicBlock>, public SILAllocated<SILBasicBlock> {`
`216`	`216`	`}`
`217`	`217`
`218`	`218`	`const SILBasicBlock *getSingleSuccessor() const {`
`219`		`- if (succ_empty() \|\| std::next(succ_begin()) != succ_end())`
`220`		`- return nullptr;`
`221`		`- return *succ_begin();`
	`219`	`+ return const_cast<SILBasicBlock *>(this)->getSingleSuccessor();`
`222`	`220`	`}`
`223`	`221`
`224`	`222`	`/// \brief Returns true if \p BB is a successor of this block.`