diff --git a/pkgs/development/compilers/llvm/10/compiler-rt.nix b/pkgs/development/compilers/llvm/10/compiler-rt.nix
index 37515b5039d8..bdc99427c27e 100644
--- a/pkgs/development/compilers/llvm/10/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/10/compiler-rt.nix
@@ -45,7 +45,7 @@ stdenv.mkDerivation rec {
     # The compiler-rt build infrastructure sniffs supported platforms on Darwin
     # and finds i386;x86_64;x86_64h. We only build for x86_64, so linking fails
     # when it tries to use libc++ and libc++api for i386.
-    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.parsed.cpu.name}"
+    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.darwinArch}"
   ];
 
   outputs = [ "out" "dev" ];
diff --git a/pkgs/development/compilers/llvm/11/compiler-rt.nix b/pkgs/development/compilers/llvm/11/compiler-rt.nix
index c42e07eac4ca..fe326b004131 100644
--- a/pkgs/development/compilers/llvm/11/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/11/compiler-rt.nix
@@ -26,7 +26,7 @@ stdenv.mkDerivation rec {
     "-DCMAKE_ASM_COMPILER_TARGET=${stdenv.hostPlatform.config}"
   ] ++ lib.optionals (stdenv.isDarwin) [
     "-DDARWIN_macosx_OVERRIDE_SDK_VERSION=ON"
-    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.parsed.cpu.name}"
+    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.darwinArch}"
   ] ++ lib.optionals (useLLVM || bareMetal || isMusl) [
     "-DCOMPILER_RT_BUILD_SANITIZERS=OFF"
     "-DCOMPILER_RT_BUILD_XRAY=OFF"
diff --git a/pkgs/development/compilers/llvm/5/compiler-rt.nix b/pkgs/development/compilers/llvm/5/compiler-rt.nix
index 909c6b190536..81dbe7048e6b 100644
--- a/pkgs/development/compilers/llvm/5/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/5/compiler-rt.nix
@@ -45,7 +45,7 @@ stdenv.mkDerivation {
     # The compiler-rt build infrastructure sniffs supported platforms on Darwin
     # and finds i386;x86_64;x86_64h. We only build for x86_64, so linking fails
     # when it tries to use libc++ and libc++api for i386.
-    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.parsed.cpu.name}"
+    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.darwinArch}"
   ];
 
   outputs = [ "out" "dev" ];
diff --git a/pkgs/development/compilers/llvm/6/compiler-rt.nix b/pkgs/development/compilers/llvm/6/compiler-rt.nix
index 6e47ffe8acaf..11d46289afe8 100644
--- a/pkgs/development/compilers/llvm/6/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/6/compiler-rt.nix
@@ -45,7 +45,7 @@ stdenv.mkDerivation {
     # The compiler-rt build infrastructure sniffs supported platforms on Darwin
     # and finds i386;x86_64;x86_64h. We only build for x86_64, so linking fails
     # when it tries to use libc++ and libc++api for i386.
-    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.parsed.cpu.name}"
+    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.darwinArch}"
   ];
 
   outputs = [ "out" "dev" ];
diff --git a/pkgs/development/compilers/llvm/7/compiler-rt.nix b/pkgs/development/compilers/llvm/7/compiler-rt.nix
index 6320a3405d27..0f91f3c5e6c1 100644
--- a/pkgs/development/compilers/llvm/7/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/7/compiler-rt.nix
@@ -45,7 +45,7 @@ stdenv.mkDerivation {
     # The compiler-rt build infrastructure sniffs supported platforms on Darwin
     # and finds i386;x86_64;x86_64h. We only build for x86_64, so linking fails
     # when it tries to use libc++ and libc++api for i386.
-    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.parsed.cpu.name}"
+    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.darwinArch}"
   ];
 
   outputs = [ "out" "dev" ];
diff --git a/pkgs/development/compilers/llvm/8/compiler-rt.nix b/pkgs/development/compilers/llvm/8/compiler-rt.nix
index 2e49ef17346d..a9dabebb59a0 100644
--- a/pkgs/development/compilers/llvm/8/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/8/compiler-rt.nix
@@ -45,7 +45,7 @@ stdenv.mkDerivation {
     # The compiler-rt build infrastructure sniffs supported platforms on Darwin
     # and finds i386;x86_64;x86_64h. We only build for x86_64, so linking fails
     # when it tries to use libc++ and libc++api for i386.
-    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.parsed.cpu.name}"
+    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.darwinArch}"
   ];
 
   outputs = [ "out" "dev" ];
diff --git a/pkgs/development/compilers/llvm/9/compiler-rt.nix b/pkgs/development/compilers/llvm/9/compiler-rt.nix
index 2ab9dc8ffa2e..1e9aa1d5d1bf 100644
--- a/pkgs/development/compilers/llvm/9/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/9/compiler-rt.nix
@@ -45,7 +45,7 @@ stdenv.mkDerivation rec {
     # The compiler-rt build infrastructure sniffs supported platforms on Darwin
     # and finds i386;x86_64;x86_64h. We only build for x86_64, so linking fails
     # when it tries to use libc++ and libc++api for i386.
-    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.parsed.cpu.name}"
+    "-DDARWIN_osx_ARCHS=${stdenv.hostPlatform.darwinArch}"
   ];
 
   outputs = [ "out" "dev" ];