Make GVN aware of instructions that write to CPU flags.

2017-10-19 12:57:55 -07:00
parent bce3c38042
commit cc0bb70c5d
4 changed files with 29 additions and 1 deletions
--- a/lib/cretonne/src/simple_gvn.rs
+++ b/lib/cretonne/src/simple_gvn.rs
@@ -10,7 +10,7 @@ use scoped_hash_map::ScopedHashMap;
 fn trivially_unsafe_for_gvn(opcode: Opcode) -> bool {
    opcode.is_call() || opcode.is_branch() || opcode.is_terminator() ||
        opcode.is_return() || opcode.can_trap() || opcode.other_side_effects() ||
-        opcode.can_store() || opcode.can_load()
+        opcode.can_store() || opcode.can_load() || opcode.writes_cpu_flags()
 }

 /// Perform simple GVN on `func`.