This amends fd874e5fb1 to correctly set
the bit width of a '!' operator to be the same width as an 'int'. This
fixes a failed assertion about unexpected bit widths that was reported
during post-commit testing.
The patch mainly focuses on the no warnings for -Wtautological-compare.
It work fine for the positive numbers but doesn't for the 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.
Fixes#42918
Differential Revision: https://reviews.llvm.org/D130510
This reverts commit 0cc3c184c7.
The changes did not account for templated code where one instantiation
may trigger the diagnostic but other instantiations will not, as in:
```
template <int I, class T>
void foo(int x) {
bool b1 = (x & sizeof(T)) == 8;
bool b2 = (x & I) == 8;
bool b3 = (x & 4) == 8;
}
void run(int x) {
foo<4, int>(8);
}
```
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
Some warnings in -Wtautological-compare subgroups are DefaultIgnore.
Adding this group to -Wmost, which is part of -Wall, will aid in their
discoverability.
Differential Revision: https://reviews.llvm.org/D69292
Taking a value and the bitwise-or it with a non-zero constant will always
result in a non-zero value. In a boolean context, this is always true.
if (x | 0x4) {} // always true, intended '&'
This patch creates a new warning group -Wtautological-bitwise-compare for this
warning. It also moves in the existing tautological bitwise comparisons into
this group. A few other changes were needed to the CFGBuilder so that all bool
contexts would be checked. The warnings in -Wtautological-bitwise-compare will
be off by default due to using the CFG.
Fixes: https://bugs.llvm.org/show_bug.cgi?id=42666
Differential Revision: https://reviews.llvm.org/D66046
llvm-svn: 375318
Aaron Ballman