Add a scale-test validation test for quadratic behavior during inlining.

Adds a stat to SILInstruction's transferNodesFromList to record the
number of times an instruction is transfered to another block. This is
the only way I can think of to detect quadratic behavior of passes
that split basic blocks.

Author: atrick

include/swift/Basic/Statistic.h

@@ -21,7 +21,9 @@
 #include <thread>
 #include <tuple>
 
-#define SWIFT_FUNC_STAT                                                 \
+#define SWIFT_FUNC_STAT SWIFT_FUNC_STAT_NAMED(DEBUG_TYPE)
+
+#define SWIFT_FUNC_STAT_NAMED(DEBUG_TYPE)                               \
   do {                                                                  \
     static llvm::Statistic FStat =                                      \
       {DEBUG_TYPE, __func__, __func__, {0}, {false}};                   \

lib/SIL/SILInstruction.cpp

@@ -86,8 +86,10 @@ transferNodesFromList(llvm::ilist_traits<SILInstruction> &L2,
   if (ThisParent == L2.getContainingBlock()) return;
 
   // Update the parent fields in the instructions.
-  for (; first != last; ++first)
+  for (; first != last; ++first) {
+    SWIFT_FUNC_STAT_NAMED("sil");
     first->ParentBB = ThisParent;
+  }
 }
 
 //===----------------------------------------------------------------------===//

validation-test/compiler_scale/array_init.swift.gyb

@@ -0,0 +1,13 @@
+// RUN: %scale-test -Onone --begin 0 --end 10 --step 1 --select transferNodesFromList %s
+// REQUIRES: OS=macosx
+// REQUIRES: asserts
+
+// Test that mandatory inlining is linear on a long series of integer
+// initialization calls.
+
+ let _: [Int] = [
+ %for i in range(0, N):
+   1,
+ %end
+   1
+ ]