Configure current jdk/hs on Linux/x86_64 host with this:

$ sh ./configure --with-freetype-include=/usr/include/freetype2/ --with-freetype-lib=/usr/lib/i386-linux-gnu/ --disable-warnings-as-errors --with-debug-level=fastdebug --openjdk-target=i386-linux-gnu --disable-precompiled-headers

Then try to build it, and see there are x86_64.cpp files compiled:

$ LOG=debug CONF=linux-x86-normal-server-fastdebug make images 2>&1 | tee log
<... build ...>
$ grep x86_64 log
 [8] EXCLUDE_FILES := jvmciCodeInstaller_x86.cpp compiledIC_aot_x86_64.cpp compilerRuntime.cpp aotCodeHeap.cpp aotCompiledMethod.cpp aotLoader.cpp compiledIC_aot.cpp args.cc
 [9] EXCLUDE_PATTERNS := x86_64
 [8] EXCLUDE_FILES := jvmciCodeInstaller_x86.cpp compiledIC_aot_x86_64.cpp compilerRuntime.cpp aotCodeHeap.cpp aotCompiledMethod.cpp aotLoader.cpp compiledIC_aot.cpp args.cc
 [9] EXCLUDE_PATTERNS := x86_64
SetupCompileNativeFile BUILD_LIBJVM_interpreterRT_x86_64.cpp
 [2] FILE := /home/shade/jdk-hs/src/hotspot/cpu/x86/interpreterRT_x86_64.cpp
SetupCompileNativeFile BUILD_LIBJVM_vtableStubs_x86_64.cpp
 [2] FILE := /home/shade/jdk-hs/src/hotspot/cpu/x86/vtableStubs_x86_64.cpp
SetupCompileNativeFile BUILD_LIBJVM_sharedRuntime_x86_64.cpp
 [2] FILE := /home/shade/jdk-hs/src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp
SetupCompileNativeFile BUILD_LIBJVM_jniFastGetField_x86_64.cpp
 [2] FILE := /home/shade/jdk-hs/src/hotspot/cpu/x86/jniFastGetField_x86_64.cpp
SetupCompileNativeFile BUILD_LIBJVM_stubRoutines_x86_64.cpp
 [2] FILE := /home/shade/jdk-hs/src/hotspot/cpu/x86/stubRoutines_x86_64.cpp
SetupCompileNativeFile BUILD_LIBJVM_stubGenerator_x86_64.cpp
 [2] FILE := /home/shade/jdk-hs/src/hotspot/cpu/x86/stubGenerator_x86_64.cpp
SetupCompileNativeFile BUILD_LIBJVM_runtime_x86_64.cpp
 [2] FILE := /home/shade/jdk-hs/src/hotspot/cpu/x86/runtime_x86_64.cpp
SetupCompileNativeFile BUILD_LIBJVM_templateInterpreterGenerator_x86_64.cpp
 [2] FILE := /home/shade/jdk-hs/src/hotspot/cpu/x86/templateInterpreterGenerator_x86_64.cpp