[llvm-bugs] [Bug 48409] New: [LLVM-COV] A blank statement after the continue statement is wrongly marked as executed in a while loop

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=48409

            Bug ID: 48409
           Summary: [LLVM-COV] A blank statement after the continue
                    statement is wrongly marked as executed in a while
                    loop
           Product: Runtime Libraries
           Version: 11.0
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: libprofile library
          Assignee: unassignedbugs at nondot.org
          Reporter: zhangxy_97 at 126.com
                CC: llvm-bugs at lists.llvm.org

$ clang -v
clang version 11.0.0
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Candidate multilib: .;@m64
Selected multilib: .;@m64

$ cat main.c
#include <time.h>
#include <stdlib.h>
#include <stdbool.h>
bool is_predicate(int percent) {
   int n = rand() % 100;
   if (n < percent) {
      return true;
   }
   return false;
}
int main(int argc,char *argv[]){
   srand((unsigned)time(NULL));
   while ( is_predicate(50) )
   {
      ;
      continue;
      ;
   }

   return 0;
}

$ clang -w -O0 -g -fcoverage-mapping -fprofle-instr-generate=main.profraw
main.c; ./a.out; llvm-profdata merge main.profraw -o main.profdata; llvm-cov
show a.out -instr-profile=main.profdata main.c > main.gcov; cat main.gcov
    1|       |#include <time.h>
    2|       |#include <stdlib.h>
    3|       |#include <stdbool.h>
    4|      2|bool is_predicate(int percent) {
    5|      2|   int n = rand() % 100;
    6|      2|   if (n < percent) {
    7|      1|      return true;
    8|      1|   }
    9|      1|   return false;
   10|      1|}
   11|      1|int main(int argc,char *argv[]){
   12|      1|   srand((unsigned)time(NULL));
   13|      2|   while ( is_predicate(50) )
   14|      1|   {
   15|      1|      ;
   16|      1|      continue;
   17|      1|      ;
   18|      0|   }
   19|      1|
   20|      1|   return 0;
   21|      1|}

Line #17 is wrongly marked as executed.

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