[PATCH] D85287: Extend -Wtautological-bitwise-compare "bitwise or with non-zero value" warnings

[Stephan Bergmann via Phabricator via cfe-commits]

sberg created this revision.
sberg added reviewers: jordan_rose, rtrieu.
Herald added a project: clang.
sberg requested review of this revision.

...to C++ constant expression operands.

(I had been puzzled why Clang had not found <https://git.libreoffice.org/core/+/
55f3a4595891a8cc22272225d1c82419f28d4ef9%5E!/> "cid#1465512 Wrong operator used"
in the LibreOffice source code, only found by Coverity Scan.  At least building
LibreOffice with this change caused no false positives.)

In C, values of const-qualified variables are never constant expressions, so
nothing should change for C code.

To avoid potential further false positives, restrict this change only to the
"bitwise or with non-zero value" warnings while keeping all other
-Wtautological-bitwise-compare warnings as-is, at least for now.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D85287

Files:
  clang/lib/Analysis/CFG.cpp
  clang/test/Sema/warn-bitwise-compare.c
  clang/test/SemaCXX/warn-bitwise-compare.cpp

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