diff --git a/compiler-rt/cmake/base-config-ix.cmake b/compiler-rt/cmake/base-config-ix.cmake
--- a/compiler-rt/cmake/base-config-ix.cmake
+++ b/compiler-rt/cmake/base-config-ix.cmake
@@ -236,9 +236,10 @@
       if(WIN32)
         test_target_arch(arm "" "" "")
       else()
+        test_target_arch(armv4t "" "-march=armv4t" "-mfloat-abi=soft")
+        test_target_arch(armv6m "" "-march=armv6m" "-mfloat-abi=soft")
         test_target_arch(arm "" "-march=armv7-a" "-mfloat-abi=soft")
         test_target_arch(armhf "" "-march=armv7-a" "-mfloat-abi=hard")
-        test_target_arch(armv6m "" "-march=armv6m" "-mfloat-abi=soft")
       endif()
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "avr")
       test_target_arch(avr "__AVR__" "--target=avr")
diff --git a/compiler-rt/cmake/builtin-config-ix.cmake b/compiler-rt/cmake/builtin-config-ix.cmake
--- a/compiler-rt/cmake/builtin-config-ix.cmake
+++ b/compiler-rt/cmake/builtin-config-ix.cmake
@@ -45,7 +45,7 @@
 ")
 
 set(ARM64 aarch64)
-set(ARM32 arm armhf armv6m armv7m armv7em armv7 armv7s armv7k armv8m.main armv8.1m.main)
+set(ARM32 arm armhf armv4t armv6m armv7m armv7em armv7 armv7s armv7k armv8m.main armv8.1m.main)
 set(AVR avr)
 set(HEXAGON hexagon)
 set(X86 i386)
diff --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -375,7 +375,9 @@
   set(i386_SOURCES ${GENERIC_SOURCES} ${x86_ARCH_SOURCES})
 endif () # if (NOT MSVC)
 
-set(arm_SOURCES
+
+# builtin support for Targets that have Arm state or have Thumb2
+set(arm_or_thumb2_base_SOURCES
   arm/fp_mode.c
   arm/bswapdi2.S
   arm/bswapsi2.S
@@ -385,6 +387,13 @@
   arm/divmodsi4.S
   arm/divsi3.S
   arm/modsi3.S
+  arm/udivmodsi4.S
+  arm/udivsi3.S
+  arm/umodsi3.S
+  ${GENERIC_SOURCES}
+)
+
+set(arm_sync_SOURCES
   arm/sync_fetch_and_add_4.S
   arm/sync_fetch_and_add_8.S
   arm/sync_fetch_and_and_4.S
@@ -405,13 +414,11 @@
   arm/sync_fetch_and_umin_8.S
   arm/sync_fetch_and_xor_4.S
   arm/sync_fetch_and_xor_8.S
-  arm/udivmodsi4.S
-  arm/udivsi3.S
-  arm/umodsi3.S
-  ${GENERIC_SOURCES}
 )
 
-set(thumb1_SOURCES
+# builtin support for Thumb-only targets with very limited Thumb2 technology,
+# such as v6-m and v8-m.baseline
+set(thumb1_base_SOURCES
   arm/divsi3.S
   arm/udivsi3.S
   arm/comparesf2.S
@@ -490,6 +497,8 @@
 set(arm_Thumb1_icache_SOURCES
   arm/sync_synchronize.S
 )
+
+# thumb1 calling into Arm to cover support
 set(arm_Thumb1_SOURCES
   ${arm_Thumb1_JT_SOURCES}
   ${arm_Thumb1_SjLj_EH_SOURCES}
@@ -498,6 +507,13 @@
   ${arm_Thumb1_icache_SOURCES}
 )
 
+# base functionality for Arm Targets prior to Arm v7-a and Armv6-m such as v6,
+# v5t, v4t
+set(arm_min_SOURCES
+  ${arm_or_thumb2_base_SOURCES}
+  ${arm_EABI_SOURCES}
+)
+
 if(MINGW)
   set(arm_SOURCES
     arm/aeabi_idivmod.S
@@ -505,18 +521,24 @@
     arm/aeabi_uidivmod.S
     arm/aeabi_uldivmod.S
     arm/chkstk.S
-    ${arm_SOURCES}
+    ${arm_or_thumb2_base_SOURCES}
+    ${arm_sync_SOURCES}
+  )
+
+  set(thumb1_SOURCES
+    ${thumb1_base_SOURCES}
   )
 elseif(NOT WIN32)
   # TODO the EABI sources should only be added to EABI targets
   set(arm_SOURCES
-    ${arm_SOURCES}
+    ${arm_or_thumb2_base_SOURCES}
+    ${arm_sync_SOURCES}
     ${arm_EABI_SOURCES}
     ${arm_Thumb1_SOURCES}
   )
 
   set(thumb1_SOURCES
-    ${thumb1_SOURCES}
+    ${thumb1_base_SOURCES}
     ${arm_EABI_SOURCES}
   )
 endif()
@@ -563,6 +585,7 @@
   )
 endif()
 
+set(armv4t_SOURCES ${arm_min_SOURCES})
 set(armhf_SOURCES ${arm_SOURCES})
 set(armv7_SOURCES ${arm_SOURCES})
 set(armv7s_SOURCES ${arm_SOURCES})