Merge pull request #15829 from eeckstein/fix-pa-forwarder

IRGen: fix a wrong tail-call attribute in a partial apply forwarder

Author: eeckstein

lib/IRGen/GenFunc.cpp

@@ -1063,6 +1063,7 @@ static llvm::Function *emitPartialApplicationForwarder(IRGenModule &IGM,
       if (RetainableValue->getType() != subIGF.IGM.RefCountedPtrTy)
         RetainableValue = subIGF.Builder.CreateBitCast(
             RetainableValue, subIGF.IGM.RefCountedPtrTy);
+      needsAllocas = true;
       auto temporary = subIGF.createAlloca(RetainableValue->getType(),
                                            subIGF.IGM.getPointerAlignment(),
                                            "partial-apply.context");

test/IRGen/partial_apply.sil

@@ -131,7 +131,7 @@ sil public_external @indirect_consumed_captured_class_param : $@convention(thin)
 // CHECK-NOT:     load
 // CHECK-NOT:     retain
 // CHECK-NOT:     release
-// CHECK:         [[RESULT:%.*]] = tail call swiftcc i64 @indirect_consumed_captured_class_param(i64 %0, %T13partial_apply10SwiftClassC** noalias nocapture dereferenceable({{.*}}) [[X_CAST]])
+// CHECK:         [[RESULT:%.*]] = call swiftcc i64 @indirect_consumed_captured_class_param(i64 %0, %T13partial_apply10SwiftClassC** noalias nocapture dereferenceable({{.*}}) [[X_CAST]])
 // CHECK-NOT:     retain
 // CHECK-NOT:     release
 // CHECK:         ret i64 [[RESULT]]