Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -8242,8 +8242,10 @@
   InGroup<CharSubscript>, DefaultIgnore;
 def err_omp_section_incomplete_type : Error<
   "section of pointer to incomplete type %0">;
-def err_omp_section_negative : Error<
-  "section %select{lower bound|length}0 is evaluated to a negative value %1">;
+def err_omp_section_not_subset_of_array : Error<
+  "array section must be a subset of the original array">;
+def err_omp_section_length_negative : Error<
+  "section length is evaluated to a negative value %0">;
 def err_omp_section_length_undefined : Error<
   "section length is unspecified and cannot be inferred because subscripted value is %select{not an array|an array of unknown bound}0">;
 def err_omp_wrong_linear_modifier : Error<
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -4304,14 +4304,13 @@
                           diag::err_omp_section_incomplete_type, Base))
     return ExprError();
 
-  if (LowerBound) {
+  if (LowerBound && !OriginalTy->isAnyPointerType()) {
     llvm::APSInt LowerBoundValue;
     if (LowerBound->EvaluateAsInt(LowerBoundValue, Context)) {
-      // OpenMP 4.0, [2.4 Array Sections]
-      // The lower-bound and length must evaluate to non-negative integers.
+      // OpenMP 4.5, [2.4 Array Sections]
+      // The array section must be a subset of the original array.
       if (LowerBoundValue.isNegative()) {
-        Diag(LowerBound->getExprLoc(), diag::err_omp_section_negative)
-            << 0 << LowerBoundValue.toString(/*Radix=*/10, /*Signed=*/true)
+        Diag(LowerBound->getExprLoc(), diag::err_omp_section_not_subset_of_array)
             << LowerBound->getSourceRange();
         return ExprError();
       }
@@ -4321,11 +4320,11 @@
   if (Length) {
     llvm::APSInt LengthValue;
     if (Length->EvaluateAsInt(LengthValue, Context)) {
-      // OpenMP 4.0, [2.4 Array Sections]
-      // The lower-bound and length must evaluate to non-negative integers.
+      // OpenMP 4.5, [2.4 Array Sections]
+      // The length must evaluate to non-negative integers.
       if (LengthValue.isNegative()) {
-        Diag(Length->getExprLoc(), diag::err_omp_section_negative)
-            << 1 << LengthValue.toString(/*Radix=*/10, /*Signed=*/true)
+        Diag(Length->getExprLoc(), diag::err_omp_section_length_negative)
+            << LengthValue.toString(/*Radix=*/10, /*Signed=*/true)
             << Length->getSourceRange();
         return ExprError();
       }
@@ -4333,7 +4332,7 @@
   } else if (ColonLoc.isValid() &&
              (OriginalTy.isNull() || (!OriginalTy->isConstantArrayType() &&
                                       !OriginalTy->isVariableArrayType()))) {
-    // OpenMP 4.0, [2.4 Array Sections]
+    // OpenMP 4.5, [2.4 Array Sections]
     // When the size of the array dimension is not known, the length must be
     // specified explicitly.
     Diag(ColonLoc, diag::err_omp_section_length_undefined)
Index: test/OpenMP/target_depend_messages.cpp
===================================================================
--- test/OpenMP/target_depend_messages.cpp
+++ test/OpenMP/target_depend_messages.cpp
@@ -66,7 +66,7 @@
   foo();
   #pragma omp target depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
   foo();
-  #pragma omp target depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target depend (in : argv[-1:0])
   foo();
   #pragma omp target depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   foo();
Index: test/OpenMP/target_enter_data_depend_messages.cpp
===================================================================
--- test/OpenMP/target_enter_data_depend_messages.cpp
+++ test/OpenMP/target_enter_data_depend_messages.cpp
@@ -68,7 +68,7 @@
   foo();
   #pragma omp target enter data map(to: i) depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
   foo();
-  #pragma omp target enter data map(to: i) depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target enter data map(to: i) depend (in : argv[-1:0])
   foo();
   #pragma omp target enter data map(to: i) depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   foo();
@@ -143,7 +143,7 @@
   foo();
   #pragma omp target enter data map(to: i) depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
   foo();
-  #pragma omp target enter data map(to: i) depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target enter data map(to: i) depend (in : argv[-1:0])
   foo();
   #pragma omp target enter data map(to: i) depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   foo();
Index: test/OpenMP/target_exit_data_depend_messages.cpp
===================================================================
--- test/OpenMP/target_exit_data_depend_messages.cpp
+++ test/OpenMP/target_exit_data_depend_messages.cpp
@@ -68,7 +68,7 @@
   foo();
   #pragma omp target exit data map(from: i) depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
   foo();
-  #pragma omp target exit data map(from: i) depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target exit data map(from: i) depend (in : argv[-1:0])
   foo();
   #pragma omp target exit data map(from: i) depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   foo();
@@ -143,7 +143,7 @@
   foo();
   #pragma omp target exit data map(from: i) depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
   foo();
-  #pragma omp target exit data map(from: i) depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target exit data map(from: i) depend (in : argv[-1:0])
   foo();
   #pragma omp target exit data map(from: i) depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   foo();
Index: test/OpenMP/target_map_messages.cpp
===================================================================
--- test/OpenMP/target_map_messages.cpp
+++ test/OpenMP/target_map_messages.cpp
@@ -51,6 +51,10 @@
     {}
     #pragma omp target map(to:b,e[:])
     {}
+    #pragma omp target map(b[-1:]) // expected-error {{array section must be a subset of the original array}}
+    {}
+    #pragma omp target map(b[:-1]) // expected-error {{section length is evaluated to a negative value -1}}
+    {}
 
     #pragma omp target map(always, tofrom: c,f)
     {}
Index: test/OpenMP/target_parallel_depend_messages.cpp
===================================================================
--- test/OpenMP/target_parallel_depend_messages.cpp
+++ test/OpenMP/target_parallel_depend_messages.cpp
@@ -66,7 +66,7 @@
   foo();
   #pragma omp target parallel depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
   foo();
-  #pragma omp target parallel depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target parallel depend (in : argv[-1:0])
   foo();
   #pragma omp target parallel depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   foo();
Index: test/OpenMP/target_parallel_for_depend_messages.cpp
===================================================================
--- test/OpenMP/target_parallel_for_depend_messages.cpp
+++ test/OpenMP/target_parallel_for_depend_messages.cpp
@@ -67,7 +67,7 @@
   for (i = 0; i < argc; ++i) foo();
   #pragma omp target parallel for depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
   for (i = 0; i < argc; ++i) foo();
-  #pragma omp target parallel for depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target parallel for depend (in : argv[-1:0])
   for (i = 0; i < argc; ++i) foo();
   #pragma omp target parallel for depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   for (i = 0; i < argc; ++i) foo();
Index: test/OpenMP/target_parallel_for_map_messages.cpp
===================================================================
--- test/OpenMP/target_parallel_for_map_messages.cpp
+++ test/OpenMP/target_parallel_for_map_messages.cpp
@@ -80,6 +80,10 @@
   for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for map(x: y) // expected-error {{incorrect map type, expected one of 'to', 'from', 'tofrom', 'alloc', 'release', or 'delete'}}
   for (i = 0; i < argc; ++i) foo();
+#pragma omp target parallel for map(l[-1:]) // expected-error 2 {{array section must be a subset of the original array}}
+  for (i = 0; i < argc; ++i) foo();
+#pragma omp target parallel for map(l[:-1]) // expected-error 2 {{section length is evaluated to a negative value -1}}
+  for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for map(x)
   for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for map(tofrom: t[:I])
@@ -196,6 +200,10 @@
   for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for map(x: y) // expected-error {{incorrect map type, expected one of 'to', 'from', 'tofrom', 'alloc', 'release', or 'delete'}}
   for (i = 0; i < argc; ++i) foo();
+#pragma omp target parallel for map(l[-1:]) // expected-error {{array section must be a subset of the original array}}
+  for (i = 0; i < argc; ++i) foo();
+#pragma omp target parallel for map(l[:-1]) // expected-error {{section length is evaluated to a negative value -1}}
+  for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for map(x)
   for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for map(to: x)
Index: test/OpenMP/target_parallel_for_simd_depend_messages.cpp
===================================================================
--- test/OpenMP/target_parallel_for_simd_depend_messages.cpp
+++ test/OpenMP/target_parallel_for_simd_depend_messages.cpp
@@ -67,7 +67,7 @@
   for (i = 0; i < argc; ++i) foo();
   #pragma omp target parallel for simd depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
   for (i = 0; i < argc; ++i) foo();
-  #pragma omp target parallel for simd depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target parallel for simd depend (in : argv[-1:0])
   for (i = 0; i < argc; ++i) foo();
   #pragma omp target parallel for simd depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   for (i = 0; i < argc; ++i) foo();
Index: test/OpenMP/target_parallel_for_simd_map_messages.cpp
===================================================================
--- test/OpenMP/target_parallel_for_simd_map_messages.cpp
+++ test/OpenMP/target_parallel_for_simd_map_messages.cpp
@@ -80,6 +80,10 @@
   for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for simd map(x: y) // expected-error {{incorrect map type, expected one of 'to', 'from', 'tofrom', 'alloc', 'release', or 'delete'}}
   for (i = 0; i < argc; ++i) foo();
+#pragma omp target parallel for simd map(l[-1:]) // expected-error 2 {{array section must be a subset of the original array}}
+  for (i = 0; i < argc; ++i) foo();
+#pragma omp target parallel for simd map(l[:-1]) // expected-error 2 {{section length is evaluated to a negative value -1}}
+  for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for simd map(x)
   for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for simd map(tofrom: t[:I])
@@ -196,6 +200,10 @@
   for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for simd map(x: y) // expected-error {{incorrect map type, expected one of 'to', 'from', 'tofrom', 'alloc', 'release', or 'delete'}}
   for (i = 0; i < argc; ++i) foo();
+#pragma omp target parallel map(l[-1:]) // expected-error {{array section must be a subset of the original array}}
+  for (i = 0; i < argc; ++i) foo();
+#pragma omp target parallel map(l[:-1]) // expected-error {{section length is evaluated to a negative value -1}}
+  for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for simd map(x)
   for (i = 0; i < argc; ++i) foo();
 #pragma omp target parallel for simd map(to: x)
Index: test/OpenMP/target_parallel_map_messages.cpp
===================================================================
--- test/OpenMP/target_parallel_map_messages.cpp
+++ test/OpenMP/target_parallel_map_messages.cpp
@@ -80,6 +80,10 @@
   foo();
 #pragma omp target parallel map(x: y) // expected-error {{incorrect map type, expected one of 'to', 'from', 'tofrom', 'alloc', 'release', or 'delete'}}
   foo();
+#pragma omp target parallel map(l[-1:]) // expected-error 2 {{array section must be a subset of the original array}}
+  foo();
+#pragma omp target parallel map(l[:-1]) // expected-error 2 {{section length is evaluated to a negative value -1}}
+  foo();
 #pragma omp target parallel map(x)
   foo();
 #pragma omp target parallel map(tofrom: t[:I])
@@ -195,6 +199,10 @@
   foo();
 #pragma omp target parallel map(x: y) // expected-error {{incorrect map type, expected one of 'to', 'from', 'tofrom', 'alloc', 'release', or 'delete'}}
   foo();
+#pragma omp target parallel map(l[-1:]) // expected-error {{array section must be a subset of the original array}}
+  foo();
+#pragma omp target parallel map(l[:-1]) // expected-error {{section length is evaluated to a negative value -1}}
+  foo();
 #pragma omp target parallel map(x)
   foo();
 #pragma omp target parallel map(to: x)
Index: test/OpenMP/target_update_depend_messages.cpp
===================================================================
--- test/OpenMP/target_update_depend_messages.cpp
+++ test/OpenMP/target_update_depend_messages.cpp
@@ -50,7 +50,7 @@
   #pragma omp target update to(z) depend(in : argv[argc: // expected-error {{expected expression}} expected-error {{expected ']'}} expected-error {{expected ')'}} expected-note {{to match this '['}} expected-note {{to match this '('}}
   #pragma omp target update to(z) depend(in : argv[argc:argc] // expected-error {{expected ')'}} expected-note {{to match this '('}}
   #pragma omp target update to(z) depend(in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
-  #pragma omp target update to(z) depend(in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target update to(z) depend(in : argv[-1:0])
   #pragma omp target update to(z) depend(in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   #pragma omp target update to(z) depend(in : argv[3:4:1]) // expected-error {{expected ']'}} expected-note {{to match this '['}}
   #pragma omp target update to(z) depend(in:a[0:1]) // expected-error {{subscripted value is not an array or pointer}}
@@ -98,7 +98,7 @@
   #pragma omp target update to(z) depend(in : argv[argc: // expected-error {{expected expression}} expected-error {{expected ']'}} expected-error {{expected ')'}} expected-note {{to match this '['}} expected-note {{to match this '('}}
   #pragma omp target update to(z) depend(in : argv[argc:argc] // expected-error {{expected ')'}} expected-note {{to match this '('}}
   #pragma omp target update to(z) depend(in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
-  #pragma omp target update to(z) depend(in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp target update to(z) depend(in : argv[-1:0])
   #pragma omp target update to(z) depend(in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   #pragma omp target update to(z) depend(in : argv[3:4:1]) // expected-error {{expected ']'}} expected-note {{to match this '['}}
   #pragma omp target update to(z) depend(in:a[0:1]) // expected-error {{subscripted value is not an array or pointer}}
Index: test/OpenMP/task_depend_messages.cpp
===================================================================
--- test/OpenMP/task_depend_messages.cpp
+++ test/OpenMP/task_depend_messages.cpp
@@ -43,7 +43,7 @@
   #pragma omp task depend (in : argv[argc: // expected-error {{expected expression}} expected-error {{expected ']'}} expected-error {{expected ')'}} expected-note {{to match this '['}} expected-note {{to match this '('}}
   #pragma omp task depend (in : argv[argc:argc] // expected-error {{expected ')'}} expected-note {{to match this '('}}
   #pragma omp task depend (in : argv[0:-1]) // expected-error {{section length is evaluated to a negative value -1}}
-  #pragma omp task depend (in : argv[-1:0]) // expected-error {{section lower bound is evaluated to a negative value -1}}
+  #pragma omp task depend (in : argv[-1:0])
   #pragma omp task depend (in : argv[:]) // expected-error {{section length is unspecified and cannot be inferred because subscripted value is not an array}}
   #pragma omp task depend (in : argv[3:4:1]) // expected-error {{expected ']'}} expected-note {{to match this '['}}
   #pragma omp task depend(in:a[0:1]) // expected-error {{subscripted value is not an array or pointer}}