diff --git a/CompilerOptimizations.md b/CompilerOptimizations.md
index 47fb6504..a01ce0f5 100644
--- a/CompilerOptimizations.md
+++ b/CompilerOptimizations.md
@@ -80,7 +80,14 @@ Gc compiler does global escape analysis across function and package boundaries.
 
 ### Function Inlining
 
-Only short and simple functions are inlined. To be inlined a function must contain less than ~40 expressions and does not contain complex things like loops, labels, closures, `panic`'s, `recover`'s, `select`'s, `switch`'es, etc.
+Only short and simple functions are inlined. To be inlined a function must conform to the rules:
+
+- function should be simple enough, the number of AST nodes must less than the budget (80);
+- function doesn't contain complex things like loops, closures, defer, recover, select, etc;
+- function isn't prefixed by go:noinline;
+- function isn't prefixed by go:uintptrescapes, since the escape information will be lost during inlining;
+- function has body;
+- etc.
 
 * **gc:** 1.0+
 * **gccgo:** -O1 and above.