diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -230,7 +230,7 @@
 set(ALL_ASAN_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64}
     ${MIPS32} ${MIPS64} ${PPC64} ${S390X})
 set(ALL_DFSAN_SUPPORTED_ARCH ${X86_64} ${MIPS64} ${ARM64})
-set(ALL_FUZZER_SUPPORTED_ARCH ${X86_64} ${ARM64})
+set(ALL_FUZZER_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM64})
 
 if(APPLE)
   set(ALL_LSAN_SUPPORTED_ARCH ${X86} ${X86_64} ${MIPS64} ${ARM64})
diff --git a/compiler-rt/lib/fuzzer/CMakeLists.txt b/compiler-rt/lib/fuzzer/CMakeLists.txt
--- a/compiler-rt/lib/fuzzer/CMakeLists.txt
+++ b/compiler-rt/lib/fuzzer/CMakeLists.txt
@@ -121,10 +121,15 @@
    COMPILER_RT_LIBCXX_PATH AND
    COMPILER_RT_LIBCXXABI_PATH)
   macro(partially_link_libcxx name dir arch)
+    if(${arch} MATCHES "i386")
+      set(EMULATION_ARGUMENT "-m" "elf_i386")
+    else()
+      set(EMULATION_ARGUMENT "")
+    endif()
     set(cxx_${arch}_merge_dir "${CMAKE_CURRENT_BINARY_DIR}/cxx_${arch}_merge.dir")
     file(MAKE_DIRECTORY ${cxx_${arch}_merge_dir})
     add_custom_command(TARGET clang_rt.${name}-${arch} POST_BUILD
-      COMMAND ${CMAKE_LINKER} --whole-archive "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" --no-whole-archive ${dir}/lib/libc++.a -r -o ${name}.o
+      COMMAND ${CMAKE_LINKER} ${EMULATION_ARGUMENT} --whole-archive "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" --no-whole-archive ${dir}/lib/libc++.a -r -o ${name}.o
       COMMAND ${CMAKE_OBJCOPY} --localize-hidden ${name}.o
       COMMAND ${CMAKE_COMMAND} -E remove "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>"
       COMMAND ${CMAKE_AR} qcs "$<TARGET_LINKER_FILE:clang_rt.${name}-${arch}>" ${name}.o
diff --git a/compiler-rt/test/fuzzer/CMakeLists.txt b/compiler-rt/test/fuzzer/CMakeLists.txt
--- a/compiler-rt/test/fuzzer/CMakeLists.txt
+++ b/compiler-rt/test/fuzzer/CMakeLists.txt
@@ -49,6 +49,7 @@
     set(LIBFUZZER_TEST_COMPILER ${COMPILER_RT_TEST_COMPILER})
     get_test_cc_for_arch(${arch} LIBFUZZER_TEST_COMPILER LIBFUZZER_TEST_FLAGS)
 
+    set(LIBFUZZER_TEST_TARGET_ARCH ${arch})
     set(LIBFUZZER_TEST_APPLE_PLATFORM "osx")
 
     set(LIBFUZZER_TEST_STDLIB ${stdlib})
diff --git a/compiler-rt/test/fuzzer/compressed.test b/compiler-rt/test/fuzzer/compressed.test
--- a/compiler-rt/test/fuzzer/compressed.test
+++ b/compiler-rt/test/fuzzer/compressed.test
@@ -1,5 +1,8 @@
 REQUIRES: linux
 REQUIRES: zlib
+# zlib is "supported" on i386 even when only for x86_64, explicitly make i386
+# unsupported by this test.
+UNSUPPORTED: i386
 # Custom mutator should find this bug, w/o custom -- no chance.
 RUN: %cpp_compiler %S/CompressedTest.cpp -o %t-CompressedTestCustom -DCUSTOM_MUTATOR -lz
 RUN: %cpp_compiler %S/CompressedTest.cpp -o %t-CompressedTestPlain -lz
diff --git a/compiler-rt/test/fuzzer/dataflow.test b/compiler-rt/test/fuzzer/dataflow.test
--- a/compiler-rt/test/fuzzer/dataflow.test
+++ b/compiler-rt/test/fuzzer/dataflow.test
@@ -1,6 +1,5 @@
 # Tests the data flow tracer.
-REQUIRES: linux
-UNSUPPORTED: aarch64
+REQUIRES: linux, x86_64
 
 # Build the tracer and the test.
 RUN: %no_fuzzer_cpp_compiler -c -fno-sanitize=all -fsanitize=dataflow  %S/../../lib/fuzzer/dataflow/DataFlow.cpp -o  %t-DataFlow.o
diff --git a/compiler-rt/test/fuzzer/fork.test b/compiler-rt/test/fuzzer/fork.test
--- a/compiler-rt/test/fuzzer/fork.test
+++ b/compiler-rt/test/fuzzer/fork.test
@@ -11,8 +11,8 @@
 RUN: %cpp_compiler %S/OutOfMemoryTest.cpp -o %t-OutOfMemoryTest
 RUN: not %run %t-OutOfMemoryTest -fork=1 -ignore_ooms=0  -rss_limit_mb=128 2>&1 | FileCheck %s --check-prefix=OOM
 
-# access-violation is the error thrown on Windows.
-CRASH: {{SEGV|access-violation}} on unknown address 0x000000000000
+# access-violation is the error thrown on Windows. Address will be smaller on i386.
+CRASH: {{SEGV|access-violation}} on unknown address {{0x000000000000|0x00000000}}
 RUN: %cpp_compiler %S/ShallowOOMDeepCrash.cpp -o %t-ShallowOOMDeepCrash
 RUN: not %run %t-ShallowOOMDeepCrash -fork=1 -rss_limit_mb=128 2>&1 | FileCheck %s --check-prefix=CRASH
 
diff --git a/compiler-rt/test/fuzzer/lit.cfg b/compiler-rt/test/fuzzer/lit.cfg
--- a/compiler-rt/test/fuzzer/lit.cfg
+++ b/compiler-rt/test/fuzzer/lit.cfg
@@ -6,6 +6,7 @@
 config.test_format = lit.formats.ShTest(True)
 config.suffixes = ['.test']
 config.test_source_root = os.path.dirname(__file__)
+config.available_features.add(config.target_arch)
 
 # Choose between lit's internal shell pipeline runner and a real shell.  If
 # LIT_USE_INTERNAL_SHELL is in the environment, we use that as an override.
@@ -24,7 +25,7 @@
 # the test runner updated.
 config.test_format = lit.formats.ShTest(execute_external)
 
-# LeakSanitizer is not supported on OSX or Windows right now.
+# LeakSanitizer is not supported on OSX, Windows, or i386 right now.
 if (sys.platform.startswith('darwin') or
     sys.platform.startswith('freebsd') or
     sys.platform.startswith('netbsd') or
@@ -35,7 +36,8 @@
   config.available_features.add('lsan')
 
 # MemorySanitizer is not supported on OSX or Windows right now
-if sys.platform.startswith('darwin') or sys.platform.startswith('win'):
+if (sys.platform.startswith('darwin') or sys.platform.startswith('win') or
+    config.target_arch == 'i386'):
   lit_config.note('msan feature unavailable')
   assert 'msan' not in config.available_features
 else:
diff --git a/compiler-rt/test/fuzzer/lit.site.cfg.in b/compiler-rt/test/fuzzer/lit.site.cfg.in
--- a/compiler-rt/test/fuzzer/lit.site.cfg.in
+++ b/compiler-rt/test/fuzzer/lit.site.cfg.in
@@ -11,6 +11,7 @@
 config.cmake_binary_dir = "@CMAKE_BINARY_DIR@"
 config.llvm_library_dir = "@LLVM_LIBRARY_DIR@"
 config.target_triple = "@TARGET_TRIPLE@"
+config.target_arch = "@LIBFUZZER_TEST_TARGET_ARCH@"
 
 # Load common config for all compiler-rt lit tests.
 lit_config.load_config(config,
diff --git a/compiler-rt/test/fuzzer/only-some-bytes.test b/compiler-rt/test/fuzzer/only-some-bytes.test
--- a/compiler-rt/test/fuzzer/only-some-bytes.test
+++ b/compiler-rt/test/fuzzer/only-some-bytes.test
@@ -1,6 +1,5 @@
 # Tests the data flow tracer.
-REQUIRES: linux
-UNSUPPORTED: aarch64
+REQUIRES: linux, x86_64
 
 # Build the tracer and the test.
 RUN: %no_fuzzer_cpp_compiler -c -fno-sanitize=all -fsanitize=dataflow  %S/../../lib/fuzzer/dataflow/DataFlow.cpp -o  %t-DataFlow.o
diff --git a/compiler-rt/test/fuzzer/trace-malloc-threaded.test b/compiler-rt/test/fuzzer/trace-malloc-threaded.test
--- a/compiler-rt/test/fuzzer/trace-malloc-threaded.test
+++ b/compiler-rt/test/fuzzer/trace-malloc-threaded.test
@@ -1,7 +1,7 @@
 // FIXME: This test infinite loops on darwin because it crashes
 // printing a stack trace repeatedly
 // FIXME: Disabled on Windows because of a crash (possibly related to above).
-UNSUPPORTED: darwin, aarch64, windows
+UNSUPPORTED: darwin, aarch64, windows, i386
 
 RUN: %cpp_compiler %S/TraceMallocThreadedTest.cpp -o \
 RUN:   %t-TraceMallocThreadedTest