[embedded] Fix a compiler crash when using generic classes in -O/-Osize

Author: kubamracek

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -967,6 +967,13 @@ SILPassPipelinePlan::getPerformancePassPipeline(const SILOptions &Options) {
   // Perform optimizations that specialize.
   addClosureSpecializePassPipeline(P);
 
+  // For embedded Swift: We need to re-run VTableSpecializer in case the
+  // performance inliner and specializer ended up discovering new generic
+  // classes.
+  if (Options.EmbeddedSwift) {
+    P.addVTableSpecializer();
+  }
+
   // Run another iteration of the SSA optimizations to optimize the
   // devirtualized inline caches and constants propagated into closures
   // (CapturePropagation).

test/embedded/osize-generics.swift

@@ -0,0 +1,15 @@
+// RUN: %target-swift-emit-ir -Osize %s -enable-experimental-feature Embedded | %FileCheck %s
+
+public func foo<T>(n: T) {
+    bar(n: 42)
+}
+
+private func bar<T>(n: T) {
+    baz(n: 42)
+}
+
+public func baz<T>(n: T) {
+    let x: ContiguousArray<Int> = .init(repeating: 0, count: 1)
+}
+
+// CHECK: define {{.*}}@main(