From 9d34307788056d8be15863697e1b7ec7ec3f204e Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanaka@apple.com>
Date: Tue, 2 Oct 2018 01:00:44 +0000
Subject: [PATCH] [CodeGen] Before entering the loop that copies a non-trivial
 array field of a non-trivial C struct, copy the preceding trivial fields that
 haven't been copied.

This commit fixes a bug where the instructions used to copy the
preceding trivial fields were emitted inside the loop body.

rdar://problem/44185064

llvm-svn: 343556
---
 clang/lib/CodeGen/CGNonTrivialStruct.cpp    |  2 ++
 clang/test/CodeGenObjC/strong-in-c-struct.m | 31 +++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/clang/lib/CodeGen/CGNonTrivialStruct.cpp b/clang/lib/CodeGen/CGNonTrivialStruct.cpp
index e9f60a9..d44d156 100644
--- a/clang/lib/CodeGen/CGNonTrivialStruct.cpp
+++ b/clang/lib/CodeGen/CGNonTrivialStruct.cpp
@@ -187,6 +187,7 @@ template <class Derived> struct GenFuncNameBase {
     if (!FK)
       return asDerived().visitTrivial(QualType(AT, 0), FD, CurStructOffset);
 
+    asDerived().flushTrivialFields();
     CharUnits FieldOffset = CurStructOffset + asDerived().getFieldOffset(FD);
     ASTContext &Ctx = asDerived().getContext();
     const ConstantArrayType *CAT = cast<ConstantArrayType>(AT);
@@ -336,6 +337,7 @@ template <class Derived> struct GenFuncBase {
       return asDerived().visitTrivial(QualType(AT, 0), FD, CurStackOffset,
                                       Addrs);
 
+    asDerived().flushTrivialFields(Addrs);
     CodeGenFunction &CGF = *this->CGF;
     ASTContext &Ctx = CGF.getContext();
 
diff --git a/clang/test/CodeGenObjC/strong-in-c-struct.m b/clang/test/CodeGenObjC/strong-in-c-struct.m
index 9c28404..494b3b2 100644
--- a/clang/test/CodeGenObjC/strong-in-c-struct.m
+++ b/clang/test/CodeGenObjC/strong-in-c-struct.m
@@ -485,8 +485,39 @@ void test_constructor_destructor_StructArray(void) {
   StructArray t;
 }
 
+// Test that StructArray's field 'd' is copied before entering the loop.
+
+// CHECK: define linkonce_odr hidden void @__copy_constructor_8_8_t0w8_AB8s24n4_t8w16_s24_AE(i8** %[[DST:.*]], i8** %[[SRC:.*]])
+// CHECK: entry:
+// CHECK: %[[DST_ADDR:.*]] = alloca i8**, align 8
+// CHECK: %[[SRC_ADDR:.*]] = alloca i8**, align 8
+// CHECK: store i8** %[[DST]], i8*** %[[DST_ADDR]], align 8
+// CHECK: store i8** %[[SRC]], i8*** %[[SRC_ADDR]], align 8
+// CHECK: %[[V0:.*]] = load i8**, i8*** %[[DST_ADDR]], align 8
+// CHECK: %[[V1:.*]] = load i8**, i8*** %[[SRC_ADDR]], align 8
+// CHECK: %[[V2:.*]] = bitcast i8** %[[V0]] to i64*
+// CHECK: %[[V3:.*]] = bitcast i8** %[[V1]] to i64*
+// CHECK: %[[V4:.*]] = load i64, i64* %[[V3]], align 8
+// CHECK: store i64 %[[V4]], i64* %[[V2]], align 8
+
+// CHECK: phi i8**
+// CHECK: phi i8**
+
+// CHECK: phi i8**
+// CHECK: phi i8**
+
+// CHECK-NOT: load i64, i64* %
+// CHECK-NOT: store i64 %
+// CHECK: call void @__copy_constructor_8_8_t0w16_s16(
+
+void test_copy_constructor_StructArray(StructArray a) {
+  StructArray t = a;
+}
+
 // Check that IRGen copies the 9-bit bitfield emitting i16 load and store.
 
+// CHECK: define void @test_copy_constructor_Bitfield0(
+
 // CHECK: define linkonce_odr hidden void @__copy_constructor_8_8_s0_t8w2(
 // CHECK: %[[V4:.*]] = bitcast i8** %{{.*}} to i8*
 // CHECK: %[[V5:.*]] = getelementptr inbounds i8, i8* %[[V4]], i64 8
-- 
2.7.4