Simplify logical operations CFG

compiler/rustc_mir_build/src/build/expr/into.rs

@@ -111,60 +111,49 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             ExprKind::LogicalOp { op, lhs, rhs } => {
                 // And:
                 //
-                // [block: If(lhs)] -true-> [else_block: If(rhs)] -true-> [true_block]
-                //        |                          | (false)
-                //        +----------false-----------+------------------> [false_block]
+                // [block: If(lhs)] -true-> [else_block: dest = (rhs)]
+                //        | (false)
+                //  [shortcurcuit_block: dest = false]
                 //
                 // Or:
                 //
-                // [block: If(lhs)] -false-> [else_block: If(rhs)] -true-> [true_block]
-                //        | (true)                   | (false)
-                //  [true_block]               [false_block]
+                // [block: If(lhs)] -false-> [else_block: dest = (rhs)]
+                //        | (true)
+                //  [shortcurcuit_block: dest = true]
 
-                let (true_block, false_block, mut else_block, join_block) = (
-                    this.cfg.start_new_block(),
+                let (shortcircuit_block, mut else_block, join_block) = (
                     this.cfg.start_new_block(),
                     this.cfg.start_new_block(),
                     this.cfg.start_new_block(),
                 );
 
                 let lhs = unpack!(block = this.as_local_operand(block, lhs));
                 let blocks = match op {
-                    LogicalOp::And => (else_block, false_block),
-                    LogicalOp::Or => (true_block, else_block),
+                    LogicalOp::And => (else_block, shortcircuit_block),
+                    LogicalOp::Or => (shortcircuit_block, else_block),
                 };
                 let term = TerminatorKind::if_(this.tcx, lhs, blocks.0, blocks.1);
                 this.cfg.terminate(block, source_info, term);
 
-                let rhs = unpack!(else_block = this.as_local_operand(else_block, rhs));
-                let term = TerminatorKind::if_(this.tcx, rhs, true_block, false_block);
-                this.cfg.terminate(else_block, source_info, term);
-
                 this.cfg.push_assign_constant(
-                    true_block,
+                    shortcircuit_block,
                     source_info,
                     destination,
                     Constant {
                         span: expr_span,
                         user_ty: None,
-                        literal: ty::Const::from_bool(this.tcx, true).into(),
+                        literal: match op {
+                            LogicalOp::And => ty::Const::from_bool(this.tcx, false).into(),
+                            LogicalOp::Or => ty::Const::from_bool(this.tcx, true).into(),
+                        },
                     },
                 );
+                this.cfg.goto(shortcircuit_block, source_info, join_block);
 
-                this.cfg.push_assign_constant(
-                    false_block,
-                    source_info,
-                    destination,
-                    Constant {
-                        span: expr_span,
-                        user_ty: None,
-                        literal: ty::Const::from_bool(this.tcx, false).into(),
-                    },
-                );
+                let rhs = unpack!(else_block = this.as_local_operand(else_block, rhs));
+                this.cfg.push_assign(else_block, source_info, destination, Rvalue::Use(rhs));
+                this.cfg.goto(else_block, source_info, join_block);
 
-                // Link up both branches:
-                this.cfg.goto(true_block, source_info, join_block);
-                this.cfg.goto(false_block, source_info, join_block);
                 join_block.unit()
             }
             ExprKind::Loop { body } => {

src/test/codegen/issue-83623-SIMD-PartialEq.rs

@@ -0,0 +1,46 @@
+// This test checks that jumps generated by logical operators can be optimized away
+
+// compile-flags: -Copt-level=3
+// only-64bit
+
+#![crate_type="lib"]
+
+pub struct Blueprint {
+    pub fuel_tank_size: u32,
+    pub payload: u32,
+    pub wheel_diameter: u32,
+    pub wheel_width: u32,
+    pub storage: u32,
+}
+
+// && chains should not prevent SIMD optimizations for primitives
+impl PartialEq for Blueprint{
+    fn eq(&self, other: &Self)->bool{
+       // CHECK-NOT: call{{.*}}bcmp
+       // CHECK-NOT: call{{.*}}memcmp
+       // CHECK-NOT: br {{.*}}
+       self.fuel_tank_size == other.fuel_tank_size
+            && self.payload == other.payload
+            && self.wheel_diameter == other.wheel_diameter
+            && self.wheel_width == other.wheel_width
+            && self.storage == other.storage
+    }
+}
+
+#[derive(PartialEq)]
+pub struct Blueprint2 {
+    pub fuel_tank_size: u32,
+    pub payload: u32,
+    pub wheel_diameter: u32,
+    pub wheel_width: u32,
+    pub storage: u32,
+}
+
+// Derived PartialEq should not generate jumps and should use SIMD
+#[no_mangle]
+pub fn partial_eq_should_not_jump(a: &Blueprint2, b:&Blueprint2)->bool{
+    // CHECK-NOT: call{{.*}}bcmp
+    // CHECK-NOT: call{{.*}}memcmp
+    // CHECK-NOT: br {{.*}}
+    a==b
+}