[Bug c++/86182] New: gcc crashes when compiling the code

[zhonghao at pku dot org.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86182

            Bug ID: 86182
           Summary: gcc crashes when compiling the code
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhonghao at pku dot org.cn
  Target Milestone: ---

The code is as follow:

#include <stdio.h>

template<typename T> static char const * f(T *t) {
 T u(*t);
 u.x = "hello world";
 printf("%s\n", u.x);
 return "initialized";
}

int main() {
 union { char const *x = f(this); };
 printf("%s\n", x);
}

gcc++ produces errors messages:

/home/haozhong/project/approach/otherreport/llvm/tmp/llvm_10531/code0.c.cpp: In
function ‘const char* f(T*) [with T = main()::<unnamed union>]’:
   
/home/haozhong/project/approach/otherreport/llvm/tmp/llvm_10531/code0.c.cpp:3:42:
error：Local declaration from a different function
     template<typename T> static char const * f(T *t) {
                                              ^
    D.2918
   
/home/haozhong/project/approach/otherreport/llvm/tmp/llvm_10531/code0.c.cpp:4:4: 
      T u(*t);
        ^
    _1 = &D.2918;
   
/home/haozhong/project/approach/otherreport/llvm/tmp/llvm_10531/code0.c.cpp:3:42:
error：Local declaration from a different function
     template<typename T> static char const * f(T *t) {
                                              ^
   
/home/haozhong/project/approach/otherreport/llvm/tmp/llvm_10531/code0.c.cpp:3:42:
error：Local declaration from a different function
    during GIMPLE pass: cfg
   
/home/haozhong/project/approach/otherreport/llvm/tmp/llvm_10531/code0.c.cpp:3:42:
internal error：verify_gimple 失败
    0xf11023 verify_gimple_in_cfg(function*, bool)
        ../../code/gcc/tree-cfg.c:5585
    0xdf808f execute_function_todo
        ../../code/gcc/passes.c:1994
    0xdf8fde execute_todo
        ../../code/gcc/passes.c:2048

    Please include the complete backtrace with any bug report.


The code comes from a bug report of clang++
https://bugs.llvm.org/show_bug.cgi?id=10531

The clang report can provide hints to understand the problem.