r358115 - Fix an off-by-one mistake in IRGen's copy-construction

[John McCall via cfe-commits]

Author: rjmccall
Date: Wed Apr 10 11:07:18 2019
New Revision: 358115

URL: http://llvm.org/viewvc/llvm-project?rev=358115&view=rev
Log:
Fix an off-by-one mistake in IRGen's copy-construction
special cases in the presence of zero-length arrays.

Patch by Joran Bigalet!

Modified:
    cfe/trunk/lib/CodeGen/CGClass.cpp
    cfe/trunk/test/CodeGenCXX/pod-member-memcpys.cpp

Modified: cfe/trunk/lib/CodeGen/CGClass.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGClass.cpp?rev=358115&r1=358114&r2=358115&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGClass.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGClass.cpp Wed Apr 10 11:07:18 2019
@@ -1008,7 +1008,7 @@ namespace {
       if (FOffset < FirstFieldOffset) {
         FirstField = F;
         FirstFieldOffset = FOffset;
-      } else if (FOffset > LastFieldOffset) {
+      } else if (FOffset >= LastFieldOffset) {
         LastField = F;
         LastFieldOffset = FOffset;
       }

Modified: cfe/trunk/test/CodeGenCXX/pod-member-memcpys.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/pod-member-memcpys.cpp?rev=358115&r1=358114&r2=358115&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/pod-member-memcpys.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/pod-member-memcpys.cpp Wed Apr 10 11:07:18 2019
@@ -45,6 +45,13 @@ struct ArrayMember {
   int w, x, y, z;
 };
 
+struct ZeroLengthArrayMember {
+    NonPOD np;
+    int a;
+    int b[0];
+    int c;
+};
+
 struct VolatileMember {
   int a, b, c, d;
   volatile int v;
@@ -109,6 +116,7 @@ CALL_AO(Basic)
 CALL_AO(PODMember)
 CALL_AO(PODLikeMember)
 CALL_AO(ArrayMember)
+CALL_AO(ZeroLengthArrayMember)
 CALL_AO(VolatileMember)
 CALL_AO(BitfieldMember)
 CALL_AO(InnerClassMember)
@@ -142,6 +150,12 @@ CALL_AO(PackedMembers)
 // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64({{.*}} align 4 {{.*}} align 4 {{.*}}i64 64, i1 {{.*}})
 // CHECK: ret %struct.ArrayMember*
 
+// ZeroLengthArrayMember copy-assignment:
+// CHECK-LABEL: define linkonce_odr dereferenceable({{[0-9]+}}) %struct.ZeroLengthArrayMember* @_ZN21ZeroLengthArrayMemberaSERKS_(%struct.ZeroLengthArrayMember* %this, %struct.ZeroLengthArrayMember* dereferenceable({{[0-9]+}}))
+// CHECK: call dereferenceable({{[0-9]+}}) %struct.NonPOD* @_ZN6NonPODaSERKS_
+// CHECK: call void @llvm.memcpy.p0i8.p0i8.i64({{.*}} align 4 {{.*}} align 4 {{.*}}i64 8, i1 {{.*}})
+// CHECK: ret %struct.ZeroLengthArrayMember*
+
 // VolatileMember copy-assignment:
 // CHECK-LABEL: define linkonce_odr dereferenceable({{[0-9]+}}) %struct.VolatileMember* @_ZN14VolatileMemberaSERKS_(%struct.VolatileMember* %this, %struct.VolatileMember* dereferenceable({{[0-9]+}}))
 // CHECK: call void @llvm.memcpy.p0i8.p0i8.i64({{.*}} align 4 {{.*}} align 4 {{.*}}i64 16, i1 {{.*}})