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Commit 84e3fdc0 authored by Takuya Shimizu's avatar Takuya Shimizu Committed by Aaron Ballman
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Fix -Wlogical-op-parentheses warning inconsistency for const and constexpr values

When using the && operator within a || operator, both Clang and GCC
produce a warning for potentially confusing operator precedence.
However, Clang avoids this warning for certain patterns, such as
a && b || 0 or a || b && 1, where the operator precedence of && and ||
does not change the result.

However, this behavior appears inconsistent when using the const or
constexpr qualifiers. For example:

bool t = true;
bool tt = true || false && t; // Warning: '&&' within '||'
const bool t = true;
bool tt = true || false && t; // No warning
const bool t = false;
bool tt = true || false && t; // Warning: '&&' within '||'

The second example does not produce a warning because
true || false && t matches the a || b && 1 pattern, while the third one
does not match any of them.

This behavior can lead to the lack of warnings for complicated
constexpr expressions. Clang should only suppress this warning when
literal values are placed in the place of t in the examples above.

This patch adds the literal-or-not check to fix the inconsistent
warnings for && within || when using const or constexpr.
parent eaa1f46f
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