tint/transform: Don't hoist textures / samplers

in the PromoteSideEffectsToDecl transform

Fixed: tint:1739
Change-Id: Iaa5a6e086708a6bba601c59962042650829795f6
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/107683
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>

src/tint/transform/promote_side_effects_to_decl.cc

@@ -281,11 +281,15 @@ class DecomposeSideEffects::CollectHoistsState : public StateBase {
                         if (var_user->ConstantValue()) {
                             return false;
                         }
-                        // Don't hoist read-only variables as they cannot receive
-                        // side-effects.
+                        // Don't hoist read-only variables as they cannot receive side-effects.
                         if (var_user->Variable()->Access() == ast::Access::kRead) {
                             return false;
                         }
+                        // Don't hoist textures / samplers as they can't be placed into a let, nor
+                        // can they have side effects.
+                        if (var_user->Variable()->Type()->IsAnyOf<sem::Texture, sem::Sampler>()) {
+                            return false;
+                        }
                         return true;
                     }
                 }

src/tint/transform/promote_side_effects_to_decl_test.cc

@@ -4081,5 +4081,54 @@ fn f() {
 
     EXPECT_EQ(expect, str(got));
 }
+
+TEST_F(PromoteSideEffectsToDeclTest, TextureSamplerParameter) {
+    auto* src = R"(
+@group(0) @binding(0) var T : texture_2d<f32>;
+@group(0) @binding(1) var S : sampler;
+
+var<private> P : vec2<f32>;
+fn side_effects() -> vec2<f32> {
+  P += vec2(1.0);
+  return P;
+}
+
+fn f(t : texture_2d<f32>, s : sampler) -> vec4<f32> {
+  return textureSample(t, s, side_effects());
+}
+
+fn m() -> vec4<f32>{
+  return f(T, S);
+}
+)";
+
+    auto* expect = R"(
+@group(0) @binding(0) var T : texture_2d<f32>;
+
+@group(0) @binding(1) var S : sampler;
+
+var<private> P : vec2<f32>;
+
+fn side_effects() -> vec2<f32> {
+  P += vec2(1.0);
+  return P;
+}
+
+fn f(t : texture_2d<f32>, s : sampler) -> vec4<f32> {
+  let tint_symbol = side_effects();
+  return textureSample(t, s, tint_symbol);
+}
+
+fn m() -> vec4<f32> {
+  return f(T, S);
+}
+)";
+
+    DataMap data;
+    auto got = Run<PromoteSideEffectsToDecl>(src, data);
+
+    EXPECT_EQ(expect, str(got));
+}
+
 }  // namespace
 }  // namespace tint::transform