new builtins: @workItemId, @workGroupId, @workGroupSize

* @workItemId returns the index of the work item in a work group for a
  dimension.
* @workGroupId returns the index of the work group in the kernel dispatch for a
  dimension.
* @workGroupSize returns the size of the work group for a dimension.

These builtins are mainly useful for GPU backends. They are currently only
implemented for the AMDGCN LLVM backend.

1 files changed, 23 insertions, 0 deletions

diff --git a/src/BuiltinFn.zig b/src/BuiltinFn.zig
index 79c6617483..4a98a5a615 100644
--- a/src/BuiltinFn.zig
+++ b/src/BuiltinFn.zig
@@ -118,6 +118,9 @@ pub const Tag = enum {
     union_init,
     Vector,
     volatile_cast,
+    work_item_id,
+    work_group_size,
+    work_group_id,
 };
 
 pub const MemLocRequirement = enum {
@@ -980,5 +983,25 @@ pub const list = list: {
                 .param_count = 1,
             },
         },
+        .{
+            "@workItemId", .{
+                .tag = .work_item_id,
+                .param_count = 1,
+            },
+        },
+        .{
+            "@workGroupSize",
+            .{
+                .tag = .work_group_size,
+                .param_count = 1,
+            },
+        },
+        .{
+            "@workGroupId",
+            .{
+                .tag = .work_group_id,
+                .param_count = 1,
+            },
+        },
     });
 };