Revert "Cranelift: Rewrite or(and(x, y), not(y)) => or(x, not(y)) (#5676)"

This reverts commit 8c9eb99.

Author: elliottt

cranelift/codegen/src/isle_prelude.rs

@@ -109,11 +109,6 @@ macro_rules! isle_common_prelude_methods {
             !x
         }
 
-        #[inline]
-        fn u64_eq(&mut self, x: u64, y: u64) -> u64 {
-            u64::from(x == y)
-        }
-
         #[inline]
         fn u64_is_zero(&mut self, value: u64) -> bool {
             0 == value

cranelift/codegen/src/opts/algebraic.isle

@@ -138,33 +138,6 @@
 (rule (simplify (bnot ty (band t x y)))
       (bor ty (bnot ty x) (bnot ty y)))
 
-;; `or(and(x, y), not(y)) == or(x, not(y))`
-(rule (simplify (bor ty
-                     (band ty x y)
-                     z @ (bnot ty y)))
-      (bor ty x z))
-;; Duplicate the rule but swap the `bor` operands because `bor` is
-;; commutative. We could, of course, add a `simplify` rule to do the commutative
-;; swap for all `bor`s but this will bloat the e-graph with many e-nodes. It is
-;; cheaper to have additional rules, rather than additional e-nodes, because we
-;; amortize their cost via ISLE's smart codegen.
-(rule (simplify (bor ty
-                     z @ (bnot ty y)
-                     (band ty x y)))
-      (bor ty x z))
-
-;; `or(and(x, y), not(y)) == or(x, not(y))` specialized for constants, since
-;; otherwise we may not know that `z == not(y)` since we don't generally expand
-;; constants in the e-graph.
-;;
-;; (No need to duplicate for commutative `bor` for this constant version because
-;; we move constants to the right.)
-(rule (simplify (bor ty
-                     (band ty x (iconst ty (u64_from_imm64 y)))
-                     z @ (iconst ty (u64_from_imm64 zk))))
-      (if (u64_eq zk (u64_not y)))
-      (bor ty x z))
-
 ;; x*2 == 2*x == x+x.
 (rule (simplify (imul ty x (iconst _ (simm32 2))))
       (iadd ty x x))

cranelift/codegen/src/prelude.isle

@@ -141,9 +141,6 @@
 (decl pure u64_not (u64) u64)
 (extern constructor u64_not u64_not)
 
-(decl pure u64_eq (u64 u64) u64)
-(extern constructor u64_eq u64_eq)
-
 (decl pure u64_sextend_u32 (u64) u64)
 (extern constructor u64_sextend_u32 u64_sextend_u32)
 

cranelift/filetests/filetests/egraph/algebraic.clif

@@ -40,7 +40,7 @@ block0(v0: i32):
     return v3
     ; check: v4 = iconst.i32 0xffff_ffe0
     ; check: v5 = band v0, v4
-    ; check: return v5
+    ; return v5
 }
 
 function %unsigned_shift_right_shift_left_i64(i64) -> i64 {
@@ -86,45 +86,3 @@ block0(v0: i64):
     ; check: v5 = band v0, v4
     ; return v5
 }
-
-function %or_and_y_with_not_y(i8, i8) -> i8 {
-block0(v0: i8, v1: i8):
-    v2 = band v0, v1
-    v3 = bnot v1
-    v4 = bor v2, v3
-    return v4
-    ; check: v5 = bor v0, v3
-    ; check: return v5
-}
-
-function %or_and_constant_with_not_constant(i8) -> i8 {
-block0(v0: i8):
-    v1 = iconst.i8 -4
-    v2 = band v0, v1
-    v3 = iconst.i8 3
-    v4 = bor v2, v3
-    return v4
-    ; check: v5 = bor v0, v3
-    ; check: return v5
-}
-
-function %or_and_y_with_not_y(i8, i8) -> i8 {
-block0(v0: i8, v1: i8):
-    v2 = band v0, v1
-    v3 = bnot v1
-    v4 = bor v3, v2
-    return v4
-    ; check: v5 = bor v0, v3
-    ; check: return v5
-}
-
-function %or_and_constant_with_not_constant(i8) -> i8 {
-block0(v0: i8):
-    v1 = iconst.i8 -4
-    v2 = band v0, v1
-    v3 = iconst.i8 3
-    v4 = bor v3, v2
-    return v4
-    ; check: v6 = bor v0, v3
-    ; check: return v6
-}