[Wasm GC] RefIs / RefEq / RefTest return a boolean (#4786)

This marks all reference operations that return 0/1 as doing so. This
allows various bitwise operations to be optimized on them.

This also marks StringEq as a boolean, though we can't test that fully yet
as Strings support is wip (no interpreter or other stuff yet).

As a driveby this moves emitsBoolean to its own file, and uses it
in getMaxBits to avoid redundancy (the redundant code paths now have
a WASM_UNREACHABLE).

1 files changed, 66 insertions, 0 deletions

diff --git a/test/lit/passes/optimize-instructions-gc.wast b/test/lit/passes/optimize-instructions-gc.wast
index 2c6498ec3..643aad5ed 100644
--- a/test/lit/passes/optimize-instructions-gc.wast
+++ b/test/lit/passes/optimize-instructions-gc.wast
@@ -2876,4 +2876,70 @@
       )
     )
   )
+
+  ;; CHECK:      (func $ref-boolean (param $x eqref) (param $y eqref)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (ref.eq
+  ;; CHECK-NEXT:    (local.get $x)
+  ;; CHECK-NEXT:    (local.get $y)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (ref.is_func
+  ;; CHECK-NEXT:    (local.get $x)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (ref.test_static $A
+  ;; CHECK-NEXT:    (local.get $x)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  ;; NOMNL:      (func $ref-boolean (type $eqref_eqref_=>_none) (param $x eqref) (param $y eqref)
+  ;; NOMNL-NEXT:  (drop
+  ;; NOMNL-NEXT:   (ref.eq
+  ;; NOMNL-NEXT:    (local.get $x)
+  ;; NOMNL-NEXT:    (local.get $y)
+  ;; NOMNL-NEXT:   )
+  ;; NOMNL-NEXT:  )
+  ;; NOMNL-NEXT:  (drop
+  ;; NOMNL-NEXT:   (ref.is_func
+  ;; NOMNL-NEXT:    (local.get $x)
+  ;; NOMNL-NEXT:   )
+  ;; NOMNL-NEXT:  )
+  ;; NOMNL-NEXT:  (drop
+  ;; NOMNL-NEXT:   (ref.test_static $A
+  ;; NOMNL-NEXT:    (local.get $x)
+  ;; NOMNL-NEXT:   )
+  ;; NOMNL-NEXT:  )
+  ;; NOMNL-NEXT: )
+  (func $ref-boolean (param $x eqref) (param $y eqref)
+    ;; ref.eq returns a boolean, so &1 on it is not needed.
+    (drop
+      (i32.and
+        (ref.eq
+          (local.get $x)
+          (local.get $y)
+        )
+        (i32.const 1)
+      )
+    )
+    ;; likewise ref.is and ref.test
+    (drop
+      (i32.and
+        (ref.is_func
+          (local.get $x)
+        )
+        (i32.const 1)
+      )
+    )
+    (drop
+      (i32.and
+        (ref.test_static $A
+          (local.get $x)
+        )
+        (i32.const 1)
+      )
+    )
+  )
 )