[Diagnostics] Support -Wtype-limits for GCC compatibility

Summary:
GCC's  -Wtype-limits (part of -Wextra):
Warn if a comparison is always true or always false due to the limited range of the data type

Reviewers: rsmith, aaron.ballman, lebedev.ri, thakis

Reviewed By: rsmith

Subscribers: lebedev.ri, jdoerfert, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58841

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@359516 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 8 insertions, 0 deletions

diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index d46f82f2a5..e46266d305 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -485,6 +485,8 @@ def TautologicalInRangeCompare : DiagGroup<"tautological-constant-in-range-compa
                                            [TautologicalTypeLimitCompare,
                                             TautologicalUnsignedZeroCompare,
                                             TautologicalUnsignedEnumZeroCompare]>;
+// For compatibility with GCC; -Wtype-limits = -Wtautological-constant-in-range-compare
+def TypeLimits : DiagGroup<"type-limits", [TautologicalInRangeCompare]>;
 def TautologicalOutOfRangeCompare : DiagGroup<"tautological-constant-out-of-range-compare">;
 def TautologicalConstantCompare : DiagGroup<"tautological-constant-compare",
                                             [TautologicalOutOfRangeCompare]>;
diff --git a/test/Sema/compare.c b/test/Sema/compare.c
index b2b486f59f..25aa13f6ba 100644
--- a/test/Sema/compare.c
+++ b/test/Sema/compare.c
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -pedantic -verify -Wsign-compare -Wtautological-constant-in-range-compare %s -Wno-unreachable-code
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -pedantic -verify -Wsign-compare -Wtype-limits %s -Wno-unreachable-code
 
 int test(char *C) { // nothing here should warn.
   return C != ((void*)0);
diff --git a/test/Sema/tautological-constant-compare.c b/test/Sema/tautological-constant-compare.c
index b242f35dc6..4f9b43b9f8 100644
--- a/test/Sema/tautological-constant-compare.c
+++ b/test/Sema/tautological-constant-compare.c
@@ -2,6 +2,8 @@
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -fsyntax-only -Wtautological-constant-in-range-compare -DTEST -verify -x c++ %s
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -fsyntax-only -Wtautological-type-limit-compare -DTEST -verify %s
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -fsyntax-only -Wtautological-type-limit-compare -DTEST -verify -x c++ %s
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -fsyntax-only -Wtype-limits -DTEST -verify %s
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -fsyntax-only -Wtype-limits -DTEST -verify -x c++ %s
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -fsyntax-only -Wextra -Wno-sign-compare -verify %s
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -fsyntax-only -Wextra -Wno-sign-compare -verify -x c++ %s
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -fsyntax-only -Wall -verify %s
diff --git a/test/Sema/tautological-constant-enum-compare.c b/test/Sema/tautological-constant-enum-compare.c
index 99481c7adb..dcac245738 100644
--- a/test/Sema/tautological-constant-enum-compare.c
+++ b/test/Sema/tautological-constant-enum-compare.c
@@ -2,6 +2,8 @@
 // RUN: %clang_cc1 -triple=x86_64-pc-win32 -fsyntax-only -DSIGNED -Wtautological-constant-in-range-compare -verify %s
 // RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -fsyntax-only -DUNSIGNED -DSILENCE -Wno-tautological-constant-compare -verify %s
 // RUN: %clang_cc1 -triple=x86_64-pc-win32 -fsyntax-only -DSIGNED -DSILENCE -Wno-tautological-constant-compare -verify %s
+// RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -fsyntax-only -DUNSIGNED -Wtype-limits -verify %s
+// RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -fsyntax-only -DUNSIGNED -DSILENCE -Wno-type-limits -verify %s
 
 int main() {
   enum A { A_a = 2 };
diff --git a/test/SemaCXX/compare.cpp b/test/SemaCXX/compare.cpp
index ee0fe01fd1..55b01e3dc3 100644
--- a/test/SemaCXX/compare.cpp
+++ b/test/SemaCXX/compare.cpp
@@ -2,6 +2,7 @@
 // on integer sizes.
 
 // RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -pedantic -verify -Wsign-compare -Wtautological-constant-in-range-compare -std=c++11 %s
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -pedantic -verify -Wsign-compare -Wtype-limits -std=c++11 %s
 
 int test0(long a, unsigned long b) {
   enum EnumA {A};