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authorRob Browning <rlb@defaultvalue.org>2024-10-05 17:18:06 -0500
committerRob Browning <rlb@defaultvalue.org>2024-10-05 19:19:57 -0500
commit9b1effb58579821ffa9357df808d5264e45fb30c (patch)
treeb5571419550b007d0b55c319d45b1d421e1d5641
parent1c96e4ab6dde18c69f1493a8e1560e80a347cd21 (diff)
downloadguile-9b1effb58579821ffa9357df808d5264e45fb30c.tar.gz
Compile with -fexcess-precision=standard for i[3456]86 when we can
* configure.ac: when -fexcess-precision=standard is available and we're building for i[3456]86, use it. This fixes floating point precision problems caused by x87 (80-bit) floating point, and detected by numbers.test. Closes: 43262
-rw-r--r--NEWS2
-rw-r--r--configure.ac24
2 files changed, 26 insertions, 0 deletions
diff --git a/NEWS b/NEWS
index b6566903b..9fd14c39d 100644
--- a/NEWS
+++ b/NEWS
@@ -24,6 +24,8 @@ Changes in 3.0.11 (since 3.0.10)
(<https://bugs.gnu.org/71891>)
** Compiler no longer crashes when inlining 3.0.9 procedure with kw args
(<https://bugs.gnu.org/72936>)
+** Guile is compiled with -fexcess-precision=standard for i[3456]86 when possible
+ (<https://debbugs.gnu.org/43262>)
Changes in 3.0.10 (since 3.0.9)
diff --git a/configure.ac b/configure.ac
index 262b171f1..ce3ae0226 100644
--- a/configure.ac
+++ b/configure.ac
@@ -62,6 +62,30 @@ AC_PROG_INSTALL
AC_PROG_CC
gl_EARLY
+AC_MSG_CHECKING([whether the compiler supports -fexcess-precision=standard])
+old_CFLAGS="$CFLAGS"
+CFLAGS="$CFLAGS -fexcess-precision=standard"
+fexcess_precision=''
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([int foo;], [])], [fexcess_precision=1]])
+CFLAGS="$old_CFLAGS"
+if test -n "$fexcess_precision"; then
+ AC_MSG_RESULT([yes])
+else
+ AC_MSG_RESULT([no])
+fi
+AC_MSG_CHECKING([whether we want -fexcess-precision=standard for $target_cpu])
+case "$target_cpu" in
+ i[[3456]]86)
+ AC_MSG_RESULT([yes])
+ if test -n "$fexcess_precision"; then
+ CFLAGS="$CFLAGS -fexcess-precision=standard"
+ else
+ AC_MSG_WARN([floating-point precision may exceed C99 rules])
+ fi
+ ;;
+ *) AC_MSG_RESULT([no]) ;;
+esac
+
AC_MSG_CHECKING([whether the compiler supports -flto])
old_CFLAGS="$CFLAGS"
LTO_CFLAGS="-flto"