[Bug breakpoints/30215] New: GDB cannot hit second time in empty while loop

["ahmet_kcbyk at hotmail dot com" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=30215

            Bug ID: 30215
           Summary: GDB cannot hit second time in empty while loop
           Product: gdb
           Version: 12.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: breakpoints
          Assignee: unassigned at sourceware dot org
          Reporter: ahmet_kcbyk at hotmail dot com
  Target Milestone: ---

This report describes a problem encountered when using GDB 12.1 to debug a C
program compiled with x86-64 11.2 gcc and the following flags: -O0 -g -gdwarf-2
-Wall -c -fmessage-length=0 -nostdinc -fno-builtin -finput-charset=Cp1252
-fcommon. 
The problem occurs when setting a breakpoint at the beginning of an empty while
loop that contains three assembly instructions: first a nop, then a compare and
a jump. The breakpoint is hit only once at the first iteration of the loop, but
not at subsequent iterations because the compare-jump block skips over the nop
instruction where the breakpoint is set. This makes it difficult to debug the
loop behavior using GDB breakpoints. 
We used Eclipse 2022-12 in Ubuntu 2022.04.1 5.19.0-32-generic linux kernel.
Here is an example code that generates the situation, the breakpoint must be
placed on the while loop. Breakpoint only hits once.

#include <stdio.h>

void foo(void) 
{
int a = 1;
while(a);
}

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