https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89993
--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> --- hjl@gnu-cfl-1 pr89993]$ gcc -mstackrealign -O2 -S b.c [hjl@gnu-cfl-1 pr89993]$ cat b.s .file "b.c" .text .p2align 4,,15 .globl tst1Foo .type tst1Foo, @function tst1Foo: .LFB526: .cfi_startproc pushq %rbp .cfi_def_cfa_offset 16 .cfi_offset 6, -16 movq %rsp, %rbp .cfi_def_cfa_register 6 andq $-16, %rsp <<<<<<<<<< Align stack without -mincoming-stack-boundary=4 subq $16, %rsp movq %rsp, %rcx call tst2Foo leave .cfi_def_cfa 7, 8 ret .cfi_endproc .LFE526: .size tst1Foo, .-tst1Foo .ident "GCC: (GNU) 8.3.1 20190311 (Red Hat 8.3.1-3)" .section .note.GNU-stack,"",@progbits [hjl@gnu-cfl-1 pr89993]$