msl: Overload matrix-vector arithmetic operators

These operators are not defined in the metal namespace when the vector
operands are packed.

Fixed: tint:1121
Change-Id: I2e8f4302e08117ca41bac6c05fb24a70d1215740
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/62480
Kokoro: Kokoro <noreply+kokoro@google.com>
Auto-Submit: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>

test/expressions/binary/mul/vec3-mat4x3/f32.wgsl

@@ -0,0 +1,11 @@
+[[block]]
+struct S {
+    matrix : mat4x3<f32>;
+    vector : vec3<f32>;
+};
+[[group(0), binding(0)]] var<uniform> data: S;
+
+[[stage(fragment)]]
+fn main() {
+  let x = data.vector * data.matrix;
+}

test/expressions/binary/mul/vec3-mat4x3/f32.wgsl.expected.hlsl

@@ -0,0 +1,16 @@
+cbuffer cbuffer_data : register(b0, space0) {
+  uint4 data[5];
+};
+
+float4x3 tint_symbol_3(uint4 buffer[5], uint offset) {
+  const uint scalar_offset = ((offset + 0u)) / 4;
+  const uint scalar_offset_1 = ((offset + 16u)) / 4;
+  const uint scalar_offset_2 = ((offset + 32u)) / 4;
+  const uint scalar_offset_3 = ((offset + 48u)) / 4;
+  return float4x3(asfloat(buffer[scalar_offset / 4].xyz), asfloat(buffer[scalar_offset_1 / 4].xyz), asfloat(buffer[scalar_offset_2 / 4].xyz), asfloat(buffer[scalar_offset_3 / 4].xyz));
+}
+
+void main() {
+  const float4 x = mul(tint_symbol_3(data, 0u), asfloat(data[4].xyz));
+  return;
+}

test/expressions/binary/mul/vec3-mat4x3/f32.wgsl.expected.msl

@@ -0,0 +1,25 @@
+#include <metal_stdlib>
+
+using namespace metal;
+
+template<typename T, int N, int M>
+inline auto operator*(matrix<T, N, M> lhs, packed_vec<T, N> rhs) {
+  return lhs * vec<T, N>(rhs);
+}
+
+template<typename T, int N, int M>
+inline auto operator*(packed_vec<T, M> lhs, matrix<T, N, M> rhs) {
+  return vec<T, M>(lhs) * rhs;
+}
+
+struct S {
+  /* 0x0000 */ float4x3 tint_symbol;
+  /* 0x0040 */ packed_float3 vector;
+  /* 0x004c */ int8_t tint_pad[4];
+};
+
+fragment void tint_symbol_1(constant S& data [[buffer(0)]]) {
+  float4 const x = (data.vector * data.tint_symbol);
+  return;
+}
+

test/expressions/binary/mul/vec3-mat4x3/f32.wgsl.expected.spvasm

@@ -0,0 +1,45 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 22
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint Fragment %main "main"
+               OpExecutionMode %main OriginUpperLeft
+               OpName %S "S"
+               OpMemberName %S 0 "matrix"
+               OpMemberName %S 1 "vector"
+               OpName %data "data"
+               OpName %main "main"
+               OpDecorate %S Block
+               OpMemberDecorate %S 0 Offset 0
+               OpMemberDecorate %S 0 ColMajor
+               OpMemberDecorate %S 0 MatrixStride 16
+               OpMemberDecorate %S 1 Offset 64
+               OpDecorate %data NonWritable
+               OpDecorate %data DescriptorSet 0
+               OpDecorate %data Binding 0
+      %float = OpTypeFloat 32
+    %v3float = OpTypeVector %float 3
+%mat4v3float = OpTypeMatrix %v3float 4
+          %S = OpTypeStruct %mat4v3float %v3float
+%_ptr_Uniform_S = OpTypePointer Uniform %S
+       %data = OpVariable %_ptr_Uniform_S Uniform
+       %void = OpTypeVoid
+          %7 = OpTypeFunction %void
+       %uint = OpTypeInt 32 0
+     %uint_1 = OpConstant %uint 1
+%_ptr_Uniform_v3float = OpTypePointer Uniform %v3float
+     %uint_0 = OpConstant %uint 0
+%_ptr_Uniform_mat4v3float = OpTypePointer Uniform %mat4v3float
+    %v4float = OpTypeVector %float 4
+       %main = OpFunction %void None %7
+         %10 = OpLabel
+         %14 = OpAccessChain %_ptr_Uniform_v3float %data %uint_1
+         %15 = OpLoad %v3float %14
+         %18 = OpAccessChain %_ptr_Uniform_mat4v3float %data %uint_0
+         %19 = OpLoad %mat4v3float %18
+         %20 = OpVectorTimesMatrix %v4float %15 %19
+               OpReturn
+               OpFunctionEnd

test/expressions/binary/mul/vec3-mat4x3/f32.wgsl.expected.wgsl

@@ -0,0 +1,12 @@
+[[block]]
+struct S {
+  matrix : mat4x3<f32>;
+  vector : vec3<f32>;
+};
+
+[[group(0), binding(0)]] var<uniform> data : S;
+
+[[stage(fragment)]]
+fn main() {
+  let x = (data.vector * data.matrix);
+}