src/tint/lang/wgsl/ast/transform/remove_unreachable_statements_test.cc

// Copyright 2021 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
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// 1. Redistributions of source code must retain the above copyright notice, this
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//    this list of conditions and the following disclaimer in the documentation
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#include "src/tint/lang/wgsl/ast/transform/remove_unreachable_statements.h"

#include "src/tint/lang/wgsl/ast/transform/helper_test.h"

namespace tint::ast::transform {
namespace {

using RemoveUnreachableStatementsTest = TransformTest;

TEST_F(RemoveUnreachableStatementsTest, ShouldRunEmptyModule) {
    auto* src = R"()";

    EXPECT_FALSE(ShouldRun<RemoveUnreachableStatements>(src));
}

TEST_F(RemoveUnreachableStatementsTest, ShouldRunHasNoUnreachable) {
    auto* src = R"(
fn f() {
  if (true) {
    var x = 1;
  }
}
)";

    EXPECT_FALSE(ShouldRun<RemoveUnreachableStatements>(src));
}

TEST_F(RemoveUnreachableStatementsTest, ShouldRunHasUnreachable) {
    auto* src = R"(
fn f() {
  return;
  if (true) {
    var x = 1;
  }
}
)";

    EXPECT_TRUE(ShouldRun<RemoveUnreachableStatements>(src));
}

TEST_F(RemoveUnreachableStatementsTest, EmptyModule) {
    auto* src = "";
    auto* expect = "";

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

TEST_F(RemoveUnreachableStatementsTest, Return) {
    auto* src = R"(
fn f() {
  return;
  var remove_me = 1;
  if (true) {
    var remove_me_too = 1;
  }
}
)";

    auto* expect = R"(
fn f() {
  return;
}
)";

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

TEST_F(RemoveUnreachableStatementsTest, NestedReturn) {
    auto* src = R"(
fn f() {
  {
    {
      return;
    }
  }
  var remove_me = 1;
  if (true) {
    var remove_me_too = 1;
  }
}
)";

    auto* expect = R"(
fn f() {
  {
    {
      return;
    }
  }
}
)";

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

// Discard has "demote-to-helper" semantics, and so code following a discard statement is not
// considered unreachable.
TEST_F(RemoveUnreachableStatementsTest, Discard) {
    auto* src = R"(
fn f() {
  discard;
  var preserve_me = 1;
}
)";

    auto* expect = R"(
fn f() {
  discard;
  var preserve_me = 1;
}
)";

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

TEST_F(RemoveUnreachableStatementsTest, IfReturn) {
    auto* src = R"(
fn f() {
  if (true) {
    return;
  }
  var preserve_me = 1;
  if (true) {
    var preserve_me_too = 1;
  }
}
)";

    auto* expect = src;

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

TEST_F(RemoveUnreachableStatementsTest, IfElseReturn) {
    auto* src = R"(
fn f() {
  if (true) {
  } else {
    return;
  }
  var preserve_me = 1;
  if (true) {
    var preserve_me_too = 1;
  }
}
)";

    auto* expect = src;

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

TEST_F(RemoveUnreachableStatementsTest, LoopWithConditionalBreak) {
    auto* src = R"(
fn f() {
  loop {
    var a = 1;
    if (true) {
      break;
    }

    continuing {
      var b = 2;
    }
  }
  var preserve_me = 1;
  if (true) {
    var preserve_me_too = 1;
  }
}
)";

    auto* expect = src;

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

TEST_F(RemoveUnreachableStatementsTest, LoopWithConditionalBreakInContinuing) {
    auto* src = R"(
fn f() {
  loop {

    continuing {
      break if true;
    }
  }
  var preserve_me = 1;
  if (true) {
    var preserve_me_too = 1;
  }
}
)";

    auto* expect = src;

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

TEST_F(RemoveUnreachableStatementsTest, SwitchCaseReturnDefaultBreak) {
    auto* src = R"(
fn f() {
  switch(1) {
    case 0: {
      return;
    }
    default: {
      break;
    }
  }
  var preserve_me = 1;
  if (true) {
    var preserve_me_too = 1;
  }
}
)";

    auto* expect = src;

    auto got = Run<RemoveUnreachableStatements>(src);

    EXPECT_EQ(expect, str(got));
}

}  // namespace
}  // namespace tint::ast::transform