--- old/make/hotspot/lib/JvmOverrideFiles.gmk	2018-09-14 10:33:35.359255508 +0200
+++ new/make/hotspot/lib/JvmOverrideFiles.gmk	2018-09-14 10:33:35.044256098 +0200
@@ -38,20 +38,26 @@
   BUILD_LIBJVM_interp_masm_x86.cpp_CXXFLAGS := -Wno-uninitialized
 endif
 
+LIBJVM_FDLIBM_COPY_OPT_FLAG := $(CXX_O_FLAG_NONE)
+# If the FDLIBM_CFLAGS variable is non-empty we know
+# that the fdlibm-fork in hotspot can get optimized
+# by using -ffp-contract=off on GCC/Clang platforms.
+ifneq ($(FDLIBM_CFLAGS), )
+  LIBJVM_FDLIBM_COPY_OPT_FLAG := $(CXX_O_FLAG_NORM)
+endif
+
 ifeq ($(OPENJDK_TARGET_OS), linux)
   BUILD_LIBJVM_ostream.cpp_CXXFLAGS := -D_FILE_OFFSET_BITS=64
   BUILD_LIBJVM_logFileOutput.cpp_CXXFLAGS := -D_FILE_OFFSET_BITS=64
 
-  ifeq ($(OPENJDK_TARGET_CPU_ARCH), x86)
-    BUILD_LIBJVM_sharedRuntimeTrig.cpp_CXXFLAGS := -DNO_PCH $(CXX_O_FLAG_NONE)
-    BUILD_LIBJVM_sharedRuntimeTrans.cpp_CXXFLAGS := -DNO_PCH $(CXX_O_FLAG_NONE)
-
-    ifeq ($(TOOLCHAIN_TYPE), clang)
-      JVM_PRECOMPILED_HEADER_EXCLUDE := \
-          sharedRuntimeTrig.cpp \
-          sharedRuntimeTrans.cpp \
-          #
-    endif
+  BUILD_LIBJVM_sharedRuntimeTrig.cpp_CXXFLAGS := -DNO_PCH $(FDLIBM_CFLAGS) $(LIBJVM_FDLIBM_COPY_OPT_FLAG)
+  BUILD_LIBJVM_sharedRuntimeTrans.cpp_CXXFLAGS := -DNO_PCH $(FDLIBM_CFLAGS) $(LIBJVM_FDLIBM_COPY_OPT_FLAG)
+
+  ifeq ($(TOOLCHAIN_TYPE), clang)
+    JVM_PRECOMPILED_HEADER_EXCLUDE := \
+	sharedRuntimeTrig.cpp \
+	sharedRuntimeTrans.cpp \
+	#
   endif
 
   ifeq ($(OPENJDK_TARGET_CPU), x86)
@@ -120,8 +126,8 @@
 
 else ifeq ($(OPENJDK_TARGET_OS), macosx)
   # The copied fdlibm routines in these files must not be optimized
-  BUILD_LIBJVM_sharedRuntimeTrans.cpp_CXXFLAGS := $(CXX_O_FLAG_NONE)
-  BUILD_LIBJVM_sharedRuntimeTrig.cpp_CXXFLAGS := $(CXX_O_FLAG_NONE)
+  BUILD_LIBJVM_sharedRuntimeTrig.cpp_CXXFLAGS := $(FDLIBM_CFLAGS) $(LIBJVM_FDLIBM_COPY_OPT_FLAG)
+  BUILD_LIBJVM_sharedRuntimeTrans.cpp_CXXFLAGS := $(FDLIBM_CFLAGS) $(LIBJVM_FDLIBM_COPY_OPT_FLAG)
   ifeq ($(TOOLCHAIN_TYPE), clang)
     # NOTE: The old build tested clang version to make sure this workaround
     # for the clang bug was still needed.