__func__ cannot share addresses with string literals in C

[Halalaluyafail3]

The following program demonstrates this issue:

#include<stdio.h>
int main(){
    static const char X[]="main";
    printf("%i\n",__func__=="main");
    printf("%i\n",X=="main");
}

Clang prints 1 then 0 with this program, when it should print 0 then 0.

The identifier __func__ shall be implicitly declared by the translator as if, immediately following
the opening brace of each function definition, the declaration

static const char __func__[] = "function-name";

appeared, where function-name is the name of the lexically-enclosing function.

Section 6.4.2.2 "Predefined identifiers" Paragraph 1 ISO/IEC 9899:2024

Unlike C++, C doesn't say that __func__ can share addresses with string literals so __func__=="main" should be zero for the same reason that X=="main" is zero.

[llvmbot]

@llvm/issue-subscribers-clang-codegen

Author: None (Halalaluyafail3)

The following program demonstrates this issue: ```c #include<stdio.h> int main(){ static const char X[]="main"; printf("%i\n",__func__=="main"); printf("%i\n",X=="main"); } ``` Clang prints 1 then 0 with this program, when it should print 0 then 0. > The identifier \_\_func\_\_ shall be implicitly declared by the translator as if, immediately following the opening brace of each function definition, the declaration > > static const char \_\_func\_\_[] = "function-name"; > > appeared, where function-name is the name of the lexically-enclosing function.

Section 6.4.2.2 "Predefined identifiers" Paragraph 1 ISO/IEC 9899:2024

Unlike C++, C doesn't say that __func__ can share addresses with string literals so __func__=="main" should be zero for the same reason that X=="main" is zero.