[cfe-dev] [PATCH] Warn against (uchar < 0) and (ushort < 0)

Xi Wang xi.wang at gmail.com
Wed Feb 22 06:50:10 PST 2012

From: Zhihao Jia <dugushuiyi at gmail.com>

This patch adds support to warn against tautological comparisons like (uchar < 0) and (ushort < 0).  See http://git.kernel.org/linus/3a7f8fb1 for an example.

Clang currently only warns against unsigned comparisons like (uint < 0).  Clang ignores (uchar < 0) and (ushort < 0) because they are essentially signed comparisons, where uchar/ushort is sign-extended to signed int.

This patch changes one existing test case, where (bool < 0) is used.

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