Merge pull request #26717 from aschwaighofer/fix_specialization_of_thin_to_thick

SpecializeOpaqueArchetypes: Fix specialization of thin_to_thick_function

Author: aschwaighofer

lib/SILOptimizer/Transforms/SpecializeOpaqueArchetypes.cpp

@@ -256,6 +256,21 @@ class OpaqueSpecializerCloner
                                           Inst->isInitializationOfDest()));
   }
 
+  SILValue remapResultType(SILLocation loc, SILValue val) {
+    auto specializedTy = remapType(val->getType());
+    if (val->getType() == specializedTy)
+      return val;
+    return createCast(loc, val, specializedTy);
+  }
+
+  void visitThinToThickFunctionInst(ThinToThickFunctionInst *Inst) {
+    getBuilder().setCurrentDebugScope(getOpScope(Inst->getDebugScope()));
+    auto loc = getOpLocation(Inst->getLoc());
+    auto opd = remapResultType(loc, getOpValue(Inst->getOperand()));
+    recordClonedInstruction(Inst, getBuilder().createThinToThickFunction(
+                                      loc, opd, getOpType(Inst->getType())));
+  }
+
   void visitStoreInst(StoreInst *Inst) {
     auto src = getOpValue(Inst->getSrc());
     auto dst = getOpValue(Inst->getDest());

test/SILOptimizer/specialize_opaque_type_archetypes.swift

@@ -539,3 +539,10 @@ struct Test : RandomAccessCollection {
         return foos[i.offset].p
     }
 }
+
+@inline(never)
+func useAbstractFunction<T: P>(_ fn: (Int64) -> T) {}
+
+public func testThinToThick() {
+  useAbstractFunction(bar)
+}