cranelift x64: use the TZCNT instruction for Ctz when it's available;

2021-01-28 12:02:47 +01:00
parent d3acd9a283
commit 6bf6612d96
4 changed files with 53 additions and 4 deletions
--- a/cranelift/codegen/src/isa/x64/inst/args.rs
+++ b/cranelift/codegen/src/isa/x64/inst/args.rs
@@ -404,6 +404,8 @@ pub enum UnaryRmROpcode {
    Bsf,
    /// Counts leading zeroes (Leading Zero CouNT).
    Lzcnt,
+    /// Counts trailing zeroes (Trailing Zero CouNT).
+    Tzcnt,
 }

 impl fmt::Debug for UnaryRmROpcode {
@@ -412,6 +414,7 @@ impl fmt::Debug for UnaryRmROpcode {
            UnaryRmROpcode::Bsr => write!(fmt, "bsr"),
            UnaryRmROpcode::Bsf => write!(fmt, "bsf"),
            UnaryRmROpcode::Lzcnt => write!(fmt, "lzcnt"),
+            UnaryRmROpcode::Tzcnt => write!(fmt, "tzcnt"),
        }
    }
 }