diff --git a/llvm/utils/release/test-release.sh b/llvm/utils/release/test-release.sh
index c3f4f42314309b..4314b565e11b03 100755
--- a/llvm/utils/release/test-release.sh
+++ b/llvm/utils/release/test-release.sh
@@ -537,6 +537,11 @@ function build_llvmCore() {
         InstallTarget="$InstallTarget install-builtins"
       fi
     fi
+    if [ "$Phase" -eq "3" ]; then
+      # Build everything at once, with the proper parallelism and verbosity,
+      # in Phase 3.
+      BuildTarget=
+    fi
 
     cd $ObjDir
     echo "# Compiling llvm $Release-$RC $Flavor"