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From f107467179428a0e3ea9e4aa9738ac12ff02822d Mon Sep 17 00:00:00 2001
From: Colin Watson <cjwatson@debian.org>
Date: Thu, 24 Feb 2022 16:04:18 +0000
Subject: [PATCH] Improve detection of -fzero-call-used-regs=all support
GCC doesn't tell us whether this option is supported unless it runs into
the situation where it would need to emit corresponding code.
---
m4/openssh.m4 | 3 +++
1 file changed, 3 insertions(+)
diff --git a/m4/openssh.m4 b/m4/openssh.m4
index 4f9c3792dc1..8c33c701b8b 100644
--- a/m4/openssh.m4
+++ b/m4/openssh.m4
@@ -14,6 +14,8 @@ AC_DEFUN([OSSH_CHECK_CFLAG_COMPILE], [{
AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
#include <stdlib.h>
#include <stdio.h>
+/* Trivial function to help test for -fzero-call-used-regs */
+void f(int n) {}
int main(int argc, char **argv) {
(void)argv;
/* Some math to catch -ftrapv problems in the toolchain */
@@ -21,6 +23,7 @@ int main(int argc, char **argv) {
float l = i * 2.1;
double m = l / 0.5;
long long int n = argc * 12345LL, o = 12345LL * (long long int)argc;
+ f(0);
printf("%d %d %d %f %f %lld %lld\n", i, j, k, l, m, n, o);
/*
* Test fallthrough behaviour. clang 10's -Wimplicit-fallthrough does
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