[msl] Add polyfill for unary negation
Unary negation of INT32_MIN is undefined behaviour in MSL, so polyfill
it by reinterpreting as a u32 and using bitwise complement.
Bug: 42251016
Change-Id: I080f7c374aff8b5899cdd833990299aa49119fa3
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/205916
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: James Price <jrprice@google.com>
diff --git a/src/tint/lang/msl/writer/raise/BUILD.bazel b/src/tint/lang/msl/writer/raise/BUILD.bazel
index 3291fb7..e820aac 100644
--- a/src/tint/lang/msl/writer/raise/BUILD.bazel
+++ b/src/tint/lang/msl/writer/raise/BUILD.bazel
@@ -46,6 +46,7 @@
"raise.cc",
"shader_io.cc",
"simd_ballot.cc",
+ "unary_polyfill.cc",
],
hdrs = [
"binary_polyfill.h",
@@ -55,6 +56,7 @@
"raise.h",
"shader_io.h",
"simd_ballot.h",
+ "unary_polyfill.h",
],
deps = [
"//src/tint/api/common",
@@ -103,6 +105,7 @@
"packed_vec3_test.cc",
"shader_io_test.cc",
"simd_ballot_test.cc",
+ "unary_polyfill_test.cc",
],
deps = [
"//src/tint/api/common",
diff --git a/src/tint/lang/msl/writer/raise/BUILD.cmake b/src/tint/lang/msl/writer/raise/BUILD.cmake
index 7d1c017..d872922 100644
--- a/src/tint/lang/msl/writer/raise/BUILD.cmake
+++ b/src/tint/lang/msl/writer/raise/BUILD.cmake
@@ -55,6 +55,8 @@
lang/msl/writer/raise/shader_io.h
lang/msl/writer/raise/simd_ballot.cc
lang/msl/writer/raise/simd_ballot.h
+ lang/msl/writer/raise/unary_polyfill.cc
+ lang/msl/writer/raise/unary_polyfill.h
)
tint_target_add_dependencies(tint_lang_msl_writer_raise lib
@@ -110,6 +112,7 @@
lang/msl/writer/raise/packed_vec3_test.cc
lang/msl/writer/raise/shader_io_test.cc
lang/msl/writer/raise/simd_ballot_test.cc
+ lang/msl/writer/raise/unary_polyfill_test.cc
)
tint_target_add_dependencies(tint_lang_msl_writer_raise_test test
diff --git a/src/tint/lang/msl/writer/raise/BUILD.gn b/src/tint/lang/msl/writer/raise/BUILD.gn
index 4b7e044..33e9d8f 100644
--- a/src/tint/lang/msl/writer/raise/BUILD.gn
+++ b/src/tint/lang/msl/writer/raise/BUILD.gn
@@ -59,6 +59,8 @@
"shader_io.h",
"simd_ballot.cc",
"simd_ballot.h",
+ "unary_polyfill.cc",
+ "unary_polyfill.h",
]
deps = [
"${dawn_root}/src/utils:utils",
@@ -105,6 +107,7 @@
"packed_vec3_test.cc",
"shader_io_test.cc",
"simd_ballot_test.cc",
+ "unary_polyfill_test.cc",
]
deps = [
"${dawn_root}/src/utils:utils",
diff --git a/src/tint/lang/msl/writer/raise/raise.cc b/src/tint/lang/msl/writer/raise/raise.cc
index 51506b3..56d1f6e 100644
--- a/src/tint/lang/msl/writer/raise/raise.cc
+++ b/src/tint/lang/msl/writer/raise/raise.cc
@@ -52,6 +52,7 @@
#include "src/tint/lang/msl/writer/raise/packed_vec3.h"
#include "src/tint/lang/msl/writer/raise/shader_io.h"
#include "src/tint/lang/msl/writer/raise/simd_ballot.h"
+#include "src/tint/lang/msl/writer/raise/unary_polyfill.h"
namespace tint::msl::writer {
@@ -135,6 +136,7 @@
RUN_TRANSFORM(raise::PackedVec3, module);
RUN_TRANSFORM(raise::SimdBallot, module);
RUN_TRANSFORM(raise::ModuleScopeVars, module);
+ RUN_TRANSFORM(raise::UnaryPolyfill, module);
RUN_TRANSFORM(raise::BinaryPolyfill, module);
RUN_TRANSFORM(raise::BuiltinPolyfill, module);
diff --git a/src/tint/lang/msl/writer/raise/unary_polyfill.cc b/src/tint/lang/msl/writer/raise/unary_polyfill.cc
new file mode 100644
index 0000000..219b29c
--- /dev/null
+++ b/src/tint/lang/msl/writer/raise/unary_polyfill.cc
@@ -0,0 +1,104 @@
+// Copyright 2024 The Dawn & Tint Authors
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+// list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "src/tint/lang/msl/writer/raise/unary_polyfill.h"
+
+#include <utility>
+
+#include "src/tint/lang/core/ir/builder.h"
+#include "src/tint/lang/core/ir/validator.h"
+
+using namespace tint::core::fluent_types; // NOLINT
+
+namespace tint::msl::writer::raise {
+namespace {
+
+/// PIMPL state for the transform.
+struct State {
+ /// The IR module.
+ core::ir::Module& ir;
+
+ /// The IR builder.
+ core::ir::Builder b{ir};
+
+ /// The type manager.
+ core::type::Manager& ty{ir.Types()};
+
+ /// Process the module.
+ void Process() {
+ // Find the unary operators that need replacing.
+ Vector<core::ir::Unary*, 4> signed_int_negate_worklist;
+ for (auto* inst : ir.Instructions()) {
+ if (auto* unary = inst->As<core::ir::Unary>()) {
+ auto op = unary->Op();
+ auto* type = unary->Val()->Type();
+ if (op == core::UnaryOp::kNegation && type->IsSignedIntegerScalarOrVector()) {
+ signed_int_negate_worklist.Push(unary);
+ }
+ }
+ }
+
+ // Replace the instructions that we found.
+ for (auto* signed_int_negate : signed_int_negate_worklist) {
+ SignedIntegerNegation(signed_int_negate);
+ }
+ }
+
+ /// Replace a signed integer negation to avoid undefined behavior.
+ /// @param unary the unary instruction
+ void SignedIntegerNegation(core::ir::Unary* unary) {
+ // Replace `-x` with `as_type<int>((~as_type<uint>(x)) + 1)`.
+ auto* signed_type = unary->Result(0)->Type();
+ auto* unsigned_type = ty.match_width(ty.u32(), signed_type);
+ b.InsertBefore(unary, [&] {
+ auto* unsigned_value = b.Bitcast(unsigned_type, unary->Val());
+ auto* complement = b.Complement(unsigned_type, unsigned_value);
+ auto* plus_one = b.Add(unsigned_type, complement, b.MatchWidth(u32(1), unsigned_type));
+ auto* result = b.Bitcast(signed_type, plus_one);
+ unary->Result(0)->ReplaceAllUsesWith(result->Result(0));
+ });
+ unary->Destroy();
+ }
+};
+
+} // namespace
+
+Result<SuccessType> UnaryPolyfill(core::ir::Module& ir) {
+ auto result = ValidateAndDumpIfNeeded(ir, "UnaryPolyfill transform",
+ core::ir::Capabilities{
+ core::ir::Capability::kAllowPointersInStructures,
+ });
+ if (result != Success) {
+ return result.Failure();
+ }
+
+ State{ir}.Process();
+
+ return Success;
+}
+
+} // namespace tint::msl::writer::raise
diff --git a/src/tint/lang/msl/writer/raise/unary_polyfill.h b/src/tint/lang/msl/writer/raise/unary_polyfill.h
new file mode 100644
index 0000000..60382c6
--- /dev/null
+++ b/src/tint/lang/msl/writer/raise/unary_polyfill.h
@@ -0,0 +1,48 @@
+// Copyright 2024 The Dawn & Tint Authors
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+// list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef SRC_TINT_LANG_MSL_WRITER_RAISE_UNARY_POLYFILL_H_
+#define SRC_TINT_LANG_MSL_WRITER_RAISE_UNARY_POLYFILL_H_
+
+#include "src/tint/utils/result/result.h"
+
+// Forward declarations.
+namespace tint::core::ir {
+class Module;
+} // namespace tint::core::ir
+
+namespace tint::msl::writer::raise {
+
+/// UnaryPolyfill is a transform that replaces unary instructions with polyfills and calls to MSL
+/// backend intrinsic functions.
+/// @param module the module to transform
+/// @returns success or failure
+Result<SuccessType> UnaryPolyfill(core::ir::Module& module);
+
+} // namespace tint::msl::writer::raise
+
+#endif // SRC_TINT_LANG_MSL_WRITER_RAISE_UNARY_POLYFILL_H_
diff --git a/src/tint/lang/msl/writer/raise/unary_polyfill_test.cc b/src/tint/lang/msl/writer/raise/unary_polyfill_test.cc
new file mode 100644
index 0000000..11088d1
--- /dev/null
+++ b/src/tint/lang/msl/writer/raise/unary_polyfill_test.cc
@@ -0,0 +1,143 @@
+// Copyright 2024 The Dawn & Tint Authors
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+// list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "src/tint/lang/msl/writer/raise/unary_polyfill.h"
+
+#include <utility>
+
+#include "gtest/gtest.h"
+#include "src/tint/lang/core/fluent_types.h"
+#include "src/tint/lang/core/ir/transform/helper_test.h"
+
+using namespace tint::core::fluent_types; // NOLINT
+using namespace tint::core::number_suffixes; // NOLINT
+
+namespace tint::msl::writer::raise {
+namespace {
+
+using MslWriter_UnaryPolyfillTest = core::ir::transform::TransformTest;
+
+TEST_F(MslWriter_UnaryPolyfillTest, Negation_F32) {
+ auto* value = b.FunctionParam<f32>("value");
+ auto* func = b.Function("foo", ty.f32());
+ func->SetParams({value});
+ b.Append(func->Block(), [&] {
+ auto* result = b.Negation<f32>(value);
+ b.Return(func, result);
+ });
+
+ auto* src = R"(
+%foo = func(%value:f32):f32 {
+ $B1: {
+ %3:f32 = negation %value
+ ret %3
+ }
+}
+)";
+ EXPECT_EQ(src, str());
+
+ auto* expect = src;
+
+ Run(UnaryPolyfill);
+
+ EXPECT_EQ(expect, str());
+}
+
+TEST_F(MslWriter_UnaryPolyfillTest, Negation_I32_Scalar) {
+ auto* value = b.FunctionParam<i32>("value");
+ auto* func = b.Function("foo", ty.i32());
+ func->SetParams({value});
+ b.Append(func->Block(), [&] {
+ auto* result = b.Negation<i32>(value);
+ b.Return(func, result);
+ });
+
+ auto* src = R"(
+%foo = func(%value:i32):i32 {
+ $B1: {
+ %3:i32 = negation %value
+ ret %3
+ }
+}
+)";
+ EXPECT_EQ(src, str());
+
+ auto* expect = R"(
+%foo = func(%value:i32):i32 {
+ $B1: {
+ %3:u32 = bitcast %value
+ %4:u32 = complement %3
+ %5:u32 = add %4, 1u
+ %6:i32 = bitcast %5
+ ret %6
+ }
+}
+)";
+
+ Run(UnaryPolyfill);
+
+ EXPECT_EQ(expect, str());
+}
+
+TEST_F(MslWriter_UnaryPolyfillTest, Negation_I32_Vector) {
+ auto* value = b.FunctionParam<vec4<i32>>("value");
+ auto* func = b.Function("foo", ty.vec4<i32>());
+ func->SetParams({value});
+ b.Append(func->Block(), [&] {
+ auto* result = b.Negation<vec4<i32>>(value);
+ b.Return(func, result);
+ });
+
+ auto* src = R"(
+%foo = func(%value:vec4<i32>):vec4<i32> {
+ $B1: {
+ %3:vec4<i32> = negation %value
+ ret %3
+ }
+}
+)";
+ EXPECT_EQ(src, str());
+
+ auto* expect = R"(
+%foo = func(%value:vec4<i32>):vec4<i32> {
+ $B1: {
+ %3:vec4<u32> = bitcast %value
+ %4:vec4<u32> = complement %3
+ %5:vec4<u32> = add %4, vec4<u32>(1u)
+ %6:vec4<i32> = bitcast %5
+ ret %6
+ }
+}
+)";
+
+ Run(UnaryPolyfill);
+
+ EXPECT_EQ(expect, str());
+}
+
+} // namespace
+} // namespace tint::msl::writer::raise
diff --git a/test/tint/expressions/unary/negate/negate.wgsl.expected.ir.msl b/test/tint/expressions/unary/negate/negate.wgsl.expected.ir.msl
index 63811fd..49c5369 100644
--- a/test/tint/expressions/unary/negate/negate.wgsl.expected.ir.msl
+++ b/test/tint/expressions/unary/negate/negate.wgsl.expected.ir.msl
@@ -2,9 +2,9 @@
using namespace metal;
int i(int x) {
- return -(x);
+ return as_type<int>((~(as_type<uint>(x)) + 1u));
}
int4 vi(int4 x) {
- return -(x);
+ return as_type<int4>((~(as_type<uint4>(x)) + uint4(1u)));
}
diff --git a/test/tint/statements/decrement/split.wgsl.expected.ir.msl b/test/tint/statements/decrement/split.wgsl.expected.ir.msl
index 2a6572d..f3f9e83 100644
--- a/test/tint/statements/decrement/split.wgsl.expected.ir.msl
+++ b/test/tint/statements/decrement/split.wgsl.expected.ir.msl
@@ -3,5 +3,5 @@
void tint_symbol() {
int b = 2;
- int c = as_type<int>((as_type<uint>(b) - as_type<uint>(-(b))));
+ int c = as_type<int>((as_type<uint>(b) - as_type<uint>(as_type<int>((~(as_type<uint>(b)) + 1u)))));
}
