diff --git a/weld/toolchain/gcc/mode/debug.mk b/weld/toolchain/gcc/mode/debug.mk
new file mode 100644
index 0000000..988072c
--- /dev/null
+++ b/weld/toolchain/gcc/mode/debug.mk
@@ -0,0 +1,10 @@
+# Copyright 2015 Andrew Gottemoller.
+#
+# This software is a copyrighted work licensed under the terms of the
+# Weld license.  Please consult the file "WELD_LICENSE" for
+# details.
+
+# This makefile defines settings for debug mode
+
+
+compiler_flag_list := -O0 -fno-inline-functions $(compiler_flag_list)
diff --git a/weld/toolchain/gcc/mode/release.mk b/weld/toolchain/gcc/mode/release.mk
new file mode 100644
index 0000000..09aa392
--- /dev/null
+++ b/weld/toolchain/gcc/mode/release.mk
@@ -0,0 +1,14 @@
+# Copyright 2015 Andrew Gottemoller.
+#
+# This software is a copyrighted work licensed under the terms of the
+# Weld license.  Please consult the file "WELD_LICENSE" for
+# details.
+
+# This makefile defines settings for release mode
+
+
+compiler_flag_list := -O3 $(compiler_flag_list)
+
+ifeq ($(type), bin)
+    link_flag_list := -Wl,-O,1 $(link_flag_list)
+endif