Revert "Make -Wstring-plus-int warns even if when the result is not out of bounds"

This reverts commit r349054.

It's causing:

FAILED: tools/clang/bindings/python/tests/CMakeFiles/check-clang-python
FAIL: test_diagnostic_range (tests.cindex.test_diagnostics.TestDiagnostics)
----------------------------------------------------------------------
Traceback (most recent call last):
  File
  "/Users/buildslave/jenkins/workspace/clang-stage1-configure-RA/llvm/tools/clang/bindings/python/tests/cindex/test_diagnostics.py",
  line 55, in test_diagnostic_range
      self.assertEqual(len(tu.diagnostics), 1)
      AssertionError: 2 != 1

======================================================================
FAIL: test_diagnostic_warning (tests.cindex.test_diagnostics.TestDiagnostics)
----------------------------------------------------------------------
Traceback (most recent call last):
  File
  "/Users/buildslave/jenkins/workspace/clang-stage1-configure-RA/llvm/tools/clang/bindings/python/tests/cindex/test_diagnostics.py",
  line 18, in test_diagnostic_warning
      self.assertEqual(len(tu.diagnostics), 2)
      AssertionError: 1 != 2

llvm-svn: 349117

1 files changed, 10 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 0771e7e1df4..4ba0fb12e70 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -9135,6 +9135,16 @@ static void diagnoseStringPlusInt(Sema &Self, SourceLocation OpLoc,
   if (!IsStringPlusInt || IndexExpr->isValueDependent())
     return;
 
+  Expr::EvalResult Result;
+  if (IndexExpr->EvaluateAsInt(Result, Self.getASTContext())) {
+    llvm::APSInt index = Result.Val.getInt();
+    unsigned StrLenWithNull = StrExpr->getLength() + 1;
+    if (index.isNonNegative() &&
+        index <= llvm::APSInt(llvm::APInt(index.getBitWidth(), StrLenWithNull),
+                              index.isUnsigned()))
+      return;
+  }
+
   SourceRange DiagRange(LHSExpr->getBeginLoc(), RHSExpr->getEndLoc());
   Self.Diag(OpLoc, diag::warn_string_plus_int)
       << DiagRange << IndexExpr->IgnoreImpCasts()->getType();