From f107467179428a0e3ea9e4aa9738ac12ff02822d Mon Sep 17 00:00:00 2001 From: Colin Watson 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 #include +/* 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