From: Pavel Roskin <proski@gnu.org>
Date: Mon, 7 May 2012 18:30:48 +0000 (+0200)
Subject: Issue 2513: Build: add -fno-tree-vrp to CXXFLAGS for gcc 4.7.0
X-Git-Tag: release/2.15.39-1~49
X-Git-Url: https://git.donarmstrong.com/?p=lilypond.git;a=commitdiff_plain;h=ca7baa2950c23337825b1c5f6e22e8fd514cd648

Issue 2513: Build: add -fno-tree-vrp to CXXFLAGS for gcc 4.7.0

That optimization breaks min() call in simultaneous-music-iterator.cc
leading to incorrect output and bogus barcheck errors.

Generalize STEPMAKE_GXXCODEGENBUG to show bug description with the flag.

GCC bug reported:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53239

Signed-off-by: David Kastrup <dak@gnu.org>
---

diff --git a/stepmake/aclocal.m4 b/stepmake/aclocal.m4
index 8be2cab11d..42c65a58cd 100644
--- a/stepmake/aclocal.m4
+++ b/stepmake/aclocal.m4
@@ -287,12 +287,16 @@ AC_DEFUN(STEPMAKE_CXXTEMPLATE, [
 ])
 
 AC_DEFUN(STEPMAKE_GXXCODEGENBUG, [
-    AC_MSG_CHECKING([options for known g++ tail call bug])
+    AC_MSG_CHECKING([options for known g++ bugs])
     case "$GXX:$CXX_VERSION" in
 	yes:400600?)
-	    AC_MSG_RESULT([-fno-optimize-sibling-calls])
+	    AC_MSG_RESULT([-fno-optimize-sibling-calls (tail call bug)])
 	    CXXFLAGS="$CXXFLAGS -fno-optimize-sibling-calls"
 	    ;;
+	yes:400700?)
+	    AC_MSG_RESULT([-fno-tree-vrp (comparison bug)])
+	    CXXFLAGS="$CXXFLAGS -fno-tree-vrp"
+	    ;;
 	*) AC_MSG_RESULT([none])
     esac
     AC_SUBST(CXXFLAGS)