llvm-project/clang
Muhammad Usman Shahid 0cc3c184c7 Missing tautological compare warnings due to unary operators
The patch mainly focuses on the lack of warnings for
-Wtautological-compare. It works fine for positive numbers but doesn't
for negative numbers. This is because the warning explicitly checks for
an IntegerLiteral AST node, but -1 is represented by a UnaryOperator
with an IntegerLiteral sub-Expr.

For the below code we have warnings:

if (0 == (5 | x)) {}

but not for

if (0 == (-5 | x)) {}

This patch changes the analysis to not look at the AST node directly to
see if it is an IntegerLiteral, but instead attempts to evaluate the
expression to see if it is an integer constant expression. This handles
unary negation signs, but also handles all the other possible operators
as well.

Fixes #42918
Differential Revision: https://reviews.llvm.org/D130510
2022-07-28 07:45:28 -04:00
..
bindings [clang] Implement ElaboratedType sugaring for types written bare 2022-07-27 11:10:54 +02:00
cmake [CMake][Fuchsia] Enable assertions and backtraces in stage 1 build 2022-07-26 06:09:38 +00:00
docs Missing tautological compare warnings due to unary operators 2022-07-28 07:45:28 -04:00
examples
include [Driver][PowerPC] Support -mtune= 2022-07-28 00:34:04 -07:00
lib Missing tautological compare warnings due to unary operators 2022-07-28 07:45:28 -04:00
runtime Fix running orc-rt tests with LLVM_BUILD_EXTERNAL_COMPILER_RT (again). 2022-07-05 15:20:08 -07:00
test Missing tautological compare warnings due to unary operators 2022-07-28 07:45:28 -04:00
tools [clang-format] Fix the return code of git-clang-format 2022-07-27 21:01:24 -07:00
unittests [clang-format] FIX: Misannotation 'auto' as trailing return type in lambdas 2022-07-27 22:20:09 +03:00
utils [Docs] Fix column ordering on clang attribute docs 2022-07-27 21:36:43 -05:00
www Revert "[Clang] Diagnose ill-formed constant expression when setting a non fixed enum to a value outside the range of the enumeration values" 2022-07-27 15:31:41 -07:00
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [cmake] Don't export `LLVM_TOOLS_INSTALL_DIR` anymore 2022-07-21 19:04:00 +00:00
CODE_OWNERS.TXT
INSTALL.txt
LICENSE.TXT
ModuleInfo.txt
NOTES.txt
README.txt

README.txt

//===----------------------------------------------------------------------===//
// C Language Family Front-end
//===----------------------------------------------------------------------===//

Welcome to Clang.  This is a compiler front-end for the C family of languages
(C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM
compiler infrastructure project.

Unlike many other compiler frontends, Clang is useful for a number of things
beyond just compiling code: we intend for Clang to be host to a number of
different source-level tools.  One example of this is the Clang Static Analyzer.

If you're interested in more (including how to build Clang) it is best to read
the relevant web sites.  Here are some pointers:

Information on Clang:             http://clang.llvm.org/
Building and using Clang:         http://clang.llvm.org/get_started.html
Clang Static Analyzer:            http://clang-analyzer.llvm.org/
Information on the LLVM project:  http://llvm.org/

If you have questions or comments about Clang, a great place to discuss them is
on the Clang forums:
  https://discourse.llvm.org/c/clang/

If you find a bug in Clang, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/