Add break-if support.

This CL adds support for `break-if` to Tint.

Bug: tint:1633, tint:1451
Change-Id: I30dfd62a3e09255624ff76ebe0cdd3a3c7cf9c5f
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/106420
Auto-Submit: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: dan sinclair <dsinclair@google.com>

test/tint/bug/tint/1064.wgsl.expected.dxc.hlsl

@@ -1,3 +1,7 @@
+bug/tint/1064.wgsl:12:9 warning: use of deprecated language feature: `break` must not be used to exit from a continuing block. Use break-if instead.
+        break;
+        ^^^^^
+
 void main() {
   while (true) {
     if (false) {

test/tint/bug/tint/1064.wgsl.expected.fxc.hlsl

@@ -1,3 +1,7 @@
+bug/tint/1064.wgsl:12:9 warning: use of deprecated language feature: `break` must not be used to exit from a continuing block. Use break-if instead.
+        break;
+        ^^^^^
+
 void main() {
   while (true) {
     if (false) {

test/tint/bug/tint/1064.wgsl.expected.glsl

@@ -1,3 +1,7 @@
+bug/tint/1064.wgsl:12:9 warning: use of deprecated language feature: `break` must not be used to exit from a continuing block. Use break-if instead.
+        break;
+        ^^^^^
+
 #version 310 es
 precision mediump float;
 

test/tint/bug/tint/1064.wgsl.expected.msl

@@ -1,3 +1,7 @@
+bug/tint/1064.wgsl:12:9 warning: use of deprecated language feature: `break` must not be used to exit from a continuing block. Use break-if instead.
+        break;
+        ^^^^^
+
 #include <metal_stdlib>
 
 using namespace metal;

test/tint/bug/tint/1064.wgsl.expected.spvasm

@@ -1,3 +1,7 @@
+bug/tint/1064.wgsl:12:9 warning: use of deprecated language feature: `break` must not be used to exit from a continuing block. Use break-if instead.
+        break;
+        ^^^^^
+
 ; SPIR-V
 ; Version: 1.3
 ; Generator: Google Tint Compiler; 0

test/tint/bug/tint/1064.wgsl.expected.wgsl

@@ -1,3 +1,7 @@
+bug/tint/1064.wgsl:12:9 warning: use of deprecated language feature: `break` must not be used to exit from a continuing block. Use break-if instead.
+        break;
+        ^^^^^
+
 @fragment
 fn main() {
   loop {

test/tint/loops/loop_with_break_if.wgsl

@@ -0,0 +1,14 @@
+fn f() -> i32 {
+    var i : i32;
+    loop {
+        if (i > 4) {
+            return i;
+        }
+        continuing {
+            i = i + 1;
+
+            break if i == 4;
+        }
+    }
+    return i;
+}

test/tint/loops/loop_with_break_if.wgsl.expected.dxc.hlsl

@@ -0,0 +1,18 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+int f() {
+  int i = 0;
+  while (true) {
+    if ((i > 4)) {
+      return i;
+    }
+    {
+      i = (i + 1);
+      if ((i == 4)) { break; }
+    }
+  }
+  return i;
+}

test/tint/loops/loop_with_break_if.wgsl.expected.fxc.hlsl

@@ -0,0 +1,18 @@
+[numthreads(1, 1, 1)]
+void unused_entry_point() {
+  return;
+}
+
+int f() {
+  int i = 0;
+  while (true) {
+    if ((i > 4)) {
+      return i;
+    }
+    {
+      i = (i + 1);
+      if ((i == 4)) { break; }
+    }
+  }
+  return i;
+}

test/tint/loops/loop_with_break_if.wgsl.expected.glsl

@@ -0,0 +1,20 @@
+#version 310 es
+
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+void unused_entry_point() {
+  return;
+}
+int f() {
+  int i = 0;
+  while (true) {
+    if ((i > 4)) {
+      return i;
+    }
+    {
+      i = (i + 1);
+      if ((i == 4)) { break; }
+    }
+  }
+  return i;
+}
+

test/tint/loops/loop_with_break_if.wgsl.expected.msl

@@ -0,0 +1,17 @@
+#include <metal_stdlib>
+
+using namespace metal;
+int f() {
+  int i = 0;
+  while (true) {
+    if ((i > 4)) {
+      return i;
+    }
+    {
+      i = as_type<int>((as_type<uint>(i) + as_type<uint>(1)));
+      if ((i == 4)) { break; }
+    }
+  }
+  return i;
+}
+

test/tint/loops/loop_with_break_if.wgsl.expected.spvasm

@@ -0,0 +1,53 @@
+; SPIR-V
+; Version: 1.3
+; Generator: Google Tint Compiler; 0
+; Bound: 29
+; Schema: 0
+               OpCapability Shader
+               OpMemoryModel Logical GLSL450
+               OpEntryPoint GLCompute %unused_entry_point "unused_entry_point"
+               OpExecutionMode %unused_entry_point LocalSize 1 1 1
+               OpName %unused_entry_point "unused_entry_point"
+               OpName %f "f"
+               OpName %i "i"
+       %void = OpTypeVoid
+          %1 = OpTypeFunction %void
+        %int = OpTypeInt 32 1
+          %5 = OpTypeFunction %int
+%_ptr_Function_int = OpTypePointer Function %int
+         %11 = OpConstantNull %int
+      %int_4 = OpConstant %int 4
+       %bool = OpTypeBool
+      %int_1 = OpConstant %int 1
+%unused_entry_point = OpFunction %void None %1
+          %4 = OpLabel
+               OpReturn
+               OpFunctionEnd
+          %f = OpFunction %int None %5
+          %8 = OpLabel
+          %i = OpVariable %_ptr_Function_int Function %11
+               OpBranch %12
+         %12 = OpLabel
+               OpLoopMerge %13 %14 None
+               OpBranch %15
+         %15 = OpLabel
+         %16 = OpLoad %int %i
+         %18 = OpSGreaterThan %bool %16 %int_4
+               OpSelectionMerge %20 None
+               OpBranchConditional %18 %21 %20
+         %21 = OpLabel
+         %22 = OpLoad %int %i
+               OpReturnValue %22
+         %20 = OpLabel
+               OpBranch %14
+         %14 = OpLabel
+         %23 = OpLoad %int %i
+         %25 = OpIAdd %int %23 %int_1
+               OpStore %i %25
+         %26 = OpLoad %int %i
+         %27 = OpIEqual %bool %26 %int_4
+               OpBranchConditional %27 %13 %12
+         %13 = OpLabel
+         %28 = OpLoad %int %i
+               OpReturnValue %28
+               OpFunctionEnd

test/tint/loops/loop_with_break_if.wgsl.expected.wgsl

@@ -0,0 +1,14 @@
+fn f() -> i32 {
+  var i : i32;
+  loop {
+    if ((i > 4)) {
+      return i;
+    }
+
+    continuing {
+      i = (i + 1);
+      break if (i == 4);
+    }
+  }
+  return i;
+}