diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 5349ccb23ce..af00f82e7f6 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -6429,29 +6429,41 @@ with pkgs;
     stdenv = libcxxStdenv;
   };
 
-  llvmPackages_34 = callPackage ../development/compilers/llvm/3.4 {
+  llvmPackages_34 = callPackage ../development/compilers/llvm/3.4 ({
     isl = isl_0_12;
-  };
+  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
+    stdenv = overrideCC stdenv gcc6;
+  });
 
-  llvmPackages_35 = callPackage ../development/compilers/llvm/3.5 {
+  llvmPackages_35 = callPackage ../development/compilers/llvm/3.5 ({
     isl = isl_0_14;
-  };
+  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
+    stdenv = overrideCC stdenv gcc6;
+  });
 
-  llvmPackages_37 = callPackage ../development/compilers/llvm/3.7 {
+  llvmPackages_37 = callPackage ../development/compilers/llvm/3.7 ({
     inherit (stdenvAdapters) overrideCC;
-  };
+  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
+    stdenv = overrideCC stdenv gcc6;
+  });
 
-  llvmPackages_38 = callPackage ../development/compilers/llvm/3.8 {
+  llvmPackages_38 = callPackage ../development/compilers/llvm/3.8 ({
     inherit (stdenvAdapters) overrideCC;
-  };
+  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
+    stdenv = overrideCC stdenv gcc6;
+  });
 
-  llvmPackages_39 = callPackage ../development/compilers/llvm/3.9 {
+  llvmPackages_39 = callPackage ../development/compilers/llvm/3.9 ({
     inherit (stdenvAdapters) overrideCC;
-  };
+  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
+    stdenv = overrideCC stdenv gcc6;
+  });
 
-  llvmPackages_4 = callPackage ../development/compilers/llvm/4 {
+  llvmPackages_4 = callPackage ../development/compilers/llvm/4 ({
     inherit (stdenvAdapters) overrideCC;
-  };
+  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
+    stdenv = overrideCC stdenv gcc6;
+  });
 
   llvmPackages_5 = callPackage ../development/compilers/llvm/5 ({
     inherit (stdenvAdapters) overrideCC;