<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/138566>138566</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Different behavior for comparison of integer comparison
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          StefanoD
      </td>
    </tr>
</table>

<pre>
    clang-version: 20.1.0
compiler flags: -Wall -O1 -Wextra -Wshadow -Weffc++ -Wno-long-long -pedantic -pedantic-errors -std=c++14

When two variables are multiplied, which leads to integer promotion and the result is not stored into a variable, following example [compiles without problems](https://godbolt.org/z/69v43z9nx):

```cpp
#include <cstdint>

bool square_less_than_method_A(uint16_t a, uint64_t b) {
    // a * a does integer promotion
    return (a * a < b);
}

int main(int, char**) {
    return 0;
}
```

Assigning the product to a variable, results in a [compile error](https://godbolt.org/z/sMso378va):

```cpp
#include <cstdint>

bool square_less_than_method_B(uint16_t a, uint64_t b) {
 const auto a_squared = a * a;
    return a_squared < b;
}

int main(int, char**) {
    return 0;
}
```

```
<source>:5:22: warning: comparison of integers of different signs: 'const int' and 'uint64_t' (aka 'unsigned long') [-Wsign-compare]
    5 |     return a_squared < b;
      | ~~~~~~~~~ ^ ~
```

The second example should also compile as `a*a` is always positive. So, I get here a false-positive warning.
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJy0VU2PozgQ_TWVS4kIbD6SAweSTKQ9rPYwK-UYObgI3jU2a5ukZw7z21eGpKdne6WZS0co2ObxXPVeuRDeq6shqqHYQXFYiSn01tWfA3XC2MPqYuWXutXCXJMbOa-sAd4gS9fZOoW0ae0wKk0OOy2uPj5KTkJrTP7IMDnRS3ACk5PvhbT3uNB1LbAdsB0mJ2MTbc11_sNkJClMUO33UULOWecx8UECPzxezHJIG0ibU08Gw93iTTglLpo8Ckc4TDqoUSuSwPZ471XboyYhPQaLygS6ksPR2cEGZQ0KIzH0hI78pAMqj8YG9ME6khFuUbxuEAk7q7W9K3NFehHDqAmh2D1E8HhXobdTiPwXTYOH4gBs04cwRmmAHYEdr1ZerA5r667Ajl-BHcvtLedft-YF2DbC5vSgTJerHcc4ZVyZVk-SEPi-9UEqE4B_WsAXazX6fybh6KzJ-3PohTkPFHorzw2wzaRMyMpzQBGTiLMyPwe8ANsiVDtIG0TEJUAUCKxBgdKSfy_ZA-soTM4gsM0TDnw_EwKPfFAdltiUCTgIZYBtYshsj20vHLBmvt5u_6BMfyB4yrCQNXO1RvmjaaOzcmoDvnNpcTMGH-N6NQjngvo1U_zv3vJqcxMfY8ru10xprfEBxRQzPC9cEoEfnh4tUr0R7y0q2vGBXvww5XtvJ9dSzJ43BfCGsdgN7sJFu-IwmiCc8tag7Z515eNYqq4jRyZgdHfuIsCqJfc5zmo-p8Cqp0hxKZbe32JeNXMPkxg7CbBqTqXYJae4nCz7UrR9ya1AqPb4M9FmwIz89vwhFJ_w23sl_uwJPbXWyNeu4Hs7aYlCe4vP6hMeoUwFsEZAmcZeI_RdfPE4Wq-CutEaP9toym94pYA9OUKBndCekifkKeh6JWsut3wrVlRnVV7mVZYxvurropRV0XZim-bbvGRdKkveZUXWbXPW5VW3UjVLWZEWaZFtCpbydSXTjLioeJZtqjbnkKc0CKXXWt-GeCRWyvuJ6oxvirJcaXEh7efvBWOG7jg_Bcbi58PV8aXkMl095KlWPvjvNEEFTfXh1e0L9eKmrMPOuv8vjzerq8np-j-nVoV-uqxbOwA7xl0et2R09i9qA7DjHJsHdnwEf6vZvwEAAP__lsAoEw">