Enable a test for the SR-15300 bug fix.

"Compiler crash when using Builtin.unreachable in initializers"

Move the test into a more general test file for future additions.

Author: atrick

test/DebugInfo/optimizer_pipeline.swift

@@ -0,0 +1,21 @@
+// RUN: %target-swift-frontend %s -emit-sil -g -Osize -parse-stdlib -parse-as-library -enable-ossa-modules -o - | %FileCheck %s
+
+// REQUIRES: asserts
+
+import Swift
+
+// Test that DCE correctly preserves debug locations.
+// SR-15300: Compiler crash when using Builtin.unreachable in initializers
+//
+// CHECK: sil_scope [[S1:[0-9]+]] { {{.*}} parent @$s18optimizer_pipeline1AVyACs13KeyValuePairsVyypypGcfC
+// CHECK: sil_scope [[S2:[0-9]+]] { {{.*}} parent [[S1]] }
+//
+// CHECK-LABEL: sil @$s18optimizer_pipeline1AVyACs13KeyValuePairsVyypypGcfC : $@convention(method) (@owned KeyValuePairs<Any, Any>, @thin A.Type) -> A {
+// CHECK: bb0(%0 : $KeyValuePairs<Any, Any>, %1 : $@thin A.Type):
+// CHECK: unreachable , scope [[S2]]
+// CHECK-LABEL: } // end sil function '$s18optimizer_pipeline1AVyACs13KeyValuePairsVyypypGcfC'
+public struct A {
+  public init(_ pairs: KeyValuePairs<Any, Any>) {
+    Builtin.unreachable()
+  }
+}