intel: Add helper to calculate GPGPU_WALKER::RightExecutionMask

Suggested by Jason.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5142>

src/intel/compiler/brw_compiler.h

@@ -1529,6 +1529,19 @@ brw_cs_simd_size_for_group_size(const struct gen_device_info *devinfo,
                                 const struct brw_cs_prog_data *cs_prog_data,
                                 unsigned group_size);
 
+/**
+ * Calculate the RightExecutionMask field used in GPGPU_WALKER.
+ */
+static inline unsigned
+brw_cs_right_mask(unsigned group_size, unsigned simd_size)
+{
+   const uint32_t remainder = group_size & (simd_size - 1);
+   if (remainder > 0)
+      return ~0u >> (32 - remainder);
+   else
+      return ~0u >> (32 - simd_size);
+}
+
 /**
  * Return true if the given shader stage is dispatched contiguously by the
  * relevant fixed function starting from channel 0 of the SIMD thread, which