omit non referenced expressions

src/back/glsl/mod.rs

@@ -1802,8 +1802,6 @@ impl<'a, W: Write> Writer<'a, W> {
                         Some(self.namer.call(name))
                     } else if self.need_bake_expressions.contains(&handle) {
                         Some(format!("{}{}", back::BAKE_PREFIX, handle.index()))
-                    } else if info.ref_count == 0 {
-                        Some(self.namer.call(""))
                     } else {
                         None
                     };

src/back/hlsl/writer.rs

@@ -1335,8 +1335,6 @@ impl<'a, W: fmt::Write> super::Writer<'a, W> {
                         Some(self.namer.call(name))
                     } else if self.need_bake_expressions.contains(&handle) {
                         Some(format!("_expr{}", handle.index()))
-                    } else if info.ref_count == 0 {
-                        Some(self.namer.call(""))
                     } else {
                         None
                     };

src/back/msl/writer.rs

@@ -2581,8 +2581,6 @@ impl<W: Write> Writer<W> {
                             // Don't assume the names in `named_expressions` are unique,
                             // or even valid. Use the `Namer`.
                             Some(self.namer.call(name))
-                        } else if info.ref_count == 0 {
-                            Some(self.namer.call(""))
                         } else {
                             // If this expression is an index that we're going to first compare
                             // against a limit, and then actually use as an index, then we may

src/back/spv/block.rs

@@ -220,6 +220,15 @@ impl<'w> BlockContext<'w> {
         expr_handle: Handle<crate::Expression>,
         block: &mut Block,
     ) -> Result<(), Error> {
+        let is_named_expression = self
+            .ir_function
+            .named_expressions
+            .contains_key(&expr_handle);
+
+        if self.fun_info[expr_handle].ref_count == 0 && !is_named_expression {
+            return Ok(());
+        }
+
         let result_type_id = self.get_expression_type_id(&self.fun_info[expr_handle].ty);
         let id = match self.ir_function.expressions[expr_handle] {
             crate::Expression::Access { base, index: _ } if self.is_intermediate(base) => {

src/back/wgsl/writer.rs

@@ -633,11 +633,6 @@ impl<W: Write> Writer<W> {
                         // Otherwise, we could accidentally write variable name instead of full expression.
                         // Also, we use sanitized names! It defense backend from generating variable with name from reserved keywords.
                         Some(self.namer.call(name))
-                    } else if info.ref_count == 0 {
-                        write!(self.out, "{level}_ = ")?;
-                        self.write_expr(module, handle, func_ctx)?;
-                        writeln!(self.out, ";")?;
-                        continue;
                     } else {
                         let expr = &func_ctx.expressions[handle];
                         let min_ref_count = expr.bake_ref_count();

src/valid/analyzer.rs

@@ -675,12 +675,17 @@ impl FunctionInfo {
                 requirements: UniformityRequirements::empty(),
             },
             E::Math {
-                arg, arg1, arg2, ..
+                fun: _,
+                arg,
+                arg1,
+                arg2,
+                arg3,
             } => {
                 let arg1_nur = arg1.and_then(|h| self.add_ref(h));
                 let arg2_nur = arg2.and_then(|h| self.add_ref(h));
+                let arg3_nur = arg3.and_then(|h| self.add_ref(h));
                 Uniformity {
-                    non_uniform_result: self.add_ref(arg).or(arg1_nur).or(arg2_nur),
+                    non_uniform_result: self.add_ref(arg).or(arg1_nur).or(arg2_nur).or(arg3_nur),
                     requirements: UniformityRequirements::empty(),
                 }
             }
@@ -868,7 +873,7 @@ impl FunctionInfo {
                 S::Loop {
                     ref body,
                     ref continuing,
-                    break_if: _,
+                    break_if,
                 } => {
                     let body_uniformity =
                         self.process_block(body, other_functions, disruptor, expression_arena)?;
@@ -879,6 +884,9 @@ impl FunctionInfo {
                         continuing_disruptor,
                         expression_arena,
                     )?;
+                    if let Some(expr) = break_if {
+                        let _ = self.add_ref(expr);
+                    }
                     body_uniformity | continuing_uniformity
                 }
                 S::Return { value } => FunctionUniformity {

tests/in/access.wgsl

@@ -40,13 +40,13 @@ fn test_matrix_within_struct_accesses() {
     idx--;
 
 	// loads
-    _ = baz.m;
-    _ = baz.m[0];
-    _ = baz.m[idx];
-    _ = baz.m[0][1];
-    _ = baz.m[0][idx];
-    _ = baz.m[idx][1];
-    _ = baz.m[idx][idx];
+    let l0 = baz.m;
+    let l1 = baz.m[0];
+    let l2 = baz.m[idx];
+    let l3 = baz.m[0][1];
+    let l4 = baz.m[0][idx];
+    let l5 = baz.m[idx][1];
+    let l6 = baz.m[idx][idx];
 
     var t = Baz(mat3x2<f32>(vec2<f32>(1.0), vec2<f32>(2.0), vec2<f32>(3.0)));
 
@@ -75,14 +75,14 @@ fn test_matrix_within_array_within_struct_accesses() {
     idx--;
 
 	// loads
-    _ = nested_mat_cx2.am;
-    _ = nested_mat_cx2.am[0];
-    _ = nested_mat_cx2.am[0][0];
-    _ = nested_mat_cx2.am[0][idx];
-    _ = nested_mat_cx2.am[0][0][1];
-    _ = nested_mat_cx2.am[0][0][idx];
-    _ = nested_mat_cx2.am[0][idx][1];
-    _ = nested_mat_cx2.am[0][idx][idx];
+    let l0 = nested_mat_cx2.am;
+    let l1 = nested_mat_cx2.am[0];
+    let l2 = nested_mat_cx2.am[0][0];
+    let l3 = nested_mat_cx2.am[0][idx];
+    let l4 = nested_mat_cx2.am[0][0][1];
+    let l5 = nested_mat_cx2.am[0][0][idx];
+    let l6 = nested_mat_cx2.am[0][idx][1];
+    let l7 = nested_mat_cx2.am[0][idx][idx];
 
     var t = MatCx2InArray(array<mat4x2<f32>, 2>());
 
@@ -134,7 +134,7 @@ fn foo_vert(@builtin(vertex_index) vi: u32) -> @builtin(position) vec4<f32> {
 	c2[vi + 1u] = 42;
 	let value = c2[vi];
 
-	_ = test_arr_as_arg(array<array<f32, 10>, 5>());
+	test_arr_as_arg(array<array<f32, 10>, 5>());
 
 	return vec4<f32>(_matrix * vec4<f32>(vec4<i32>(value)), 2.0);
 }

tests/in/array-in-ctor.wgsl

@@ -6,5 +6,5 @@ var<storage> ah: Ah;
 
 @compute @workgroup_size(1)
 fn cs_main() {
-    _ = ah;
+    let ah = ah;
 }

tests/in/atomicOps.wgsl

@@ -34,14 +34,14 @@ fn cs_main(@builtin(local_invocation_id) id: vec3<u32>) {
 
     workgroupBarrier();
 
-    atomicLoad(&storage_atomic_scalar);
-    atomicLoad(&storage_atomic_arr[1]);
-    atomicLoad(&storage_struct.atomic_scalar);
-    atomicLoad(&storage_struct.atomic_arr[1]);
-    atomicLoad(&workgroup_atomic_scalar);
-    atomicLoad(&workgroup_atomic_arr[1]);
-    atomicLoad(&workgroup_struct.atomic_scalar);
-    atomicLoad(&workgroup_struct.atomic_arr[1]);
+    let l0 = atomicLoad(&storage_atomic_scalar);
+    let l1 = atomicLoad(&storage_atomic_arr[1]);
+    let l2 = atomicLoad(&storage_struct.atomic_scalar);
+    let l3 = atomicLoad(&storage_struct.atomic_arr[1]);
+    let l4 = atomicLoad(&workgroup_atomic_scalar);
+    let l5 = atomicLoad(&workgroup_atomic_arr[1]);
+    let l6 = atomicLoad(&workgroup_struct.atomic_scalar);
+    let l7 = atomicLoad(&workgroup_struct.atomic_arr[1]);
 
     workgroupBarrier();
 

tests/in/globals.wgsl

@@ -45,17 +45,17 @@ fn test_msl_packed_vec3() {
     let data = alignment;
 
     // loads
-    _ = data.v3;
-    _ = data.v3.zx;
+    let l0 = data.v3;
+    let l1 = data.v3.zx;
     test_msl_packed_vec3_as_arg(data.v3);
 
     // matrix vector multiplication
-    _ = data.v3 * mat3x3<f32>();
-    _ = mat3x3<f32>() * data.v3;
+    let mvm0 = data.v3 * mat3x3<f32>();
+    let mvm1 = mat3x3<f32>() * data.v3;
 
     // scalar vector multiplication
-    _ = data.v3 * 2.0;
-    _ = 2.0 * data.v3;
+    let svm0 = data.v3 * 2.0;
+    let svm1 = 2.0 * data.v3;
 }
 
 @compute @workgroup_size(1)