diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1df9e40bebd..05e6e7d0e22 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2015-10-16  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* i386/x86-tune.def (X86_TUNE_ALWAYS_FANCY_MATH_387): Disable
+	for Lakemont.
+
 2015-10-16  Andrew MacLeod  <amacleod@redhat.com>
 
 	* config/tilepro/gen-mul-tables.cc: Adjust include files.
diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def
index 05f97376d01..b2d39219124 100644
--- a/gcc/config/i386/x86-tune.def
+++ b/gcc/config/i386/x86-tune.def
@@ -435,7 +435,7 @@ DEF_TUNE (X86_TUNE_DOUBLE_WITH_ADD, "double_with_add", ~m_386)
    such as fsqrt, fprem, fsin, fcos, fsincos etc.
    Should be enabled for all targets that always has coprocesor.  */
 DEF_TUNE (X86_TUNE_ALWAYS_FANCY_MATH_387, "always_fancy_math_387",
-          ~(m_386 | m_486))
+          ~(m_386 | m_486 | m_LAKEMONT))
 
 /* X86_TUNE_UNROLL_STRLEN: Produce (quite lame) unrolled sequence for
    inline strlen.  This affects only -minline-all-stringops mode. By