From: Richard Trieu <rtrieu@google.com>
Date: Thu, 15 Nov 2012 03:43:50 +0000 (+0000)
Subject: Fix an off-by-one error by switching < to <= in -Wtautological-constant-out-of-range... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5d1cf4f292cb060b1973eb197607fc6d5716bd12;p=clang

Fix an off-by-one error by switching < to <= in -Wtautological-constant-out-of-range-compare and added test case.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@168023 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 7fd28b6191..05fa2a0663 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -4385,7 +4385,7 @@ static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E,
       // Check to see if the constant is equivalent to a negative value
       // cast to CommonT.
       if (S.Context.getIntWidth(ConstantT) == S.Context.getIntWidth(CommonT) &&
-          Value.isNegative() && Value.getMinSignedBits() < OtherWidth)
+          Value.isNegative() && Value.getMinSignedBits() <= OtherWidth)
         return;
       // The constant value rests between values that OtherT can represent after
       // conversion.  Relational comparison still works, but equality
diff --git a/test/SemaCXX/compare.cpp b/test/SemaCXX/compare.cpp
index 155da1b8d1..05980baf6d 100644
--- a/test/SemaCXX/compare.cpp
+++ b/test/SemaCXX/compare.cpp
@@ -311,6 +311,7 @@ void test7(unsigned long other) {
   (void)((int)other != (unsigned long)(0x00000000ffffffff)); // expected-warning{{true}}
   (void)((int)other != (unsigned long)(0x000000000fffffff));
   (void)((int)other < (unsigned long)(0x00000000ffffffff));  // expected-warning{{different signs}}
+  (void)((int)other == (unsigned)(0x800000000));
 
   // Common unsigned, other unsigned, constant signed
   (void)((unsigned long)other != (int)(0xffffffff));  // expected-warning{{different signs}}