Bug#1112585: g++-15: Assembler warning: no SFrame FDE emitted

[Matthias Klose]

Control: reassign -1 src:binutils

On 31.08.25 09:03, Ingo Saitz wrote:
Package: g++-15
Version: 15.2.0-2
Severity: normal
Dear Maintainer,

std::format emits a warning when compiling with -O2 -march=broadwell:

$ cat warn.cc
#include <format>

int main() {
     (void)std::format("{}", 3.14152);
}
$ g++ -std=c++20 -O2 -march=broadwell warn.cc -c
/tmp/ccPn7jw8.s: Assembler messages:
/tmp/ccPn7jw8.s: Warning: no SFrame FDE emitted; non-SP/FP register 10 in 
.cfi_def_cfa
$ g++ -std=c++20 -O3 -march=broadwell warn.cc -c
/tmp/ccXYo09Q.s: Assembler messages:
/tmp/ccXYo09Q.s: Warning: no SFrame FDE emitted; non-SP/FP register 10 in 
.cfi_def_cfa
/tmp/ccXYo09Q.s: Warning: no SFrame FDE emitted; non-SP/FP register 10 in 
.cfi_def_cfa
/tmp/ccXYo09Q.s: Warning: no SFrame FDE emitted; non-SP/FP register 10 in 
.cfi_def_cfa
/tmp/ccXYo09Q.s: Warning: no SFrame FDE emitted; non-SP/FP register 10 in 
.cfi_def_cfa
$

As far as i can see this does not impact either the program nor
compiling with -Werror enabled, but I have no idea what's going on and
if this is harmless indeed.

these are harmless, and I'll also disable this specific warning in an 
upcoming binutils upload.