| Issue |
136812
|
| Summary |
[clang-tidy] overflow builtins always write their output operand
|
| Labels |
clang-tidy
|
| Assignees |
|
| Reporter |
resistor
|
Consider the following code:
```
int test(int elementSize, int elementCount)
{
int bufferSize;
int allocSize;
bool overflow = __builtin_mul_overflow(elementCount, elementSize, &bufferSize);
overflow |= __builtin_add_overflow(4, bufferSize, &allocSize);
if (overflow)
return -1;
return allocSize;
}
```
clang-tidy-20 produces the following false-positive warning:
```
foo.cpp:6:14: warning: 2nd function call argument is an uninitialized value [clang-analyzer-core.CallAndMessage]
6 | overflow |= __builtin_add_overflow(4, bufferSize, &allocSize);
```
This seems to be because it does not understand that the prior call to `__builtin_mul_overflow` will always write to `bufferSize`.
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