GDB seems to corrupt values on AVX calculations simply by setting a breakpoint to the start of a function, it works fine when using SSE Below are the steps I did to reproduce the bug $ gcc --version gcc (GCC) 10.1.0 Copyright (C) 2020 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ gdb --version GNU gdb (GDB) 9.2 Copyright (C) 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. $ uname -a Linux harrison 5.7.11-arch1-1 #1 SMP PREEMPT Wed, 29 Jul 2020 21:38:21 +0000 x86_64 GNU/Linux $ cat main.c #include <stdio.h> float transform(float x){ float k = x / 10.0f; return k; } void main(){ float r = transform(3.21f); fprintf(stderr,"Result: %f\n",r); } $ gcc -g -Og -mavx -o test main.c $ ./test Result: 0.321000 $ gdb ./test GNU gdb (GDB) 9.2 Copyright (C) 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-pc-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from ./test... (gdb) break 4 Breakpoint 1 at 0x1139: file main.c, line 4. (gdb) run Starting program: /home/harrison/dev/testebug/test Breakpoint 1, transform (x=3.21000004) at main.c:4 4 float k = x / 10.0f; (gdb) c Continuing. Result: inf [Inferior 1 (process 18125) exited with code 014] (gdb) quit