From 2f334e8baf7fef57577a974750ebe679787e9d61 Mon Sep 17 00:00:00 2001
From: Kenneth Graunke <kenneth@whitecape.org>
Date: Fri, 27 Dec 2024 02:59:54 -0800
Subject: [PATCH] nir: Add a nir_def_first_component_read() helper

Similar to nir_def_last_component_read().  Just a little nicer than
prodding at the bitmask of components read directly.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32888>
---
 src/compiler/nir/nir.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index a53a0a2b888..756ca610852 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -5102,6 +5102,12 @@ nir_component_mask_t nir_def_components_read(const nir_def *def);
 bool nir_def_all_uses_are_fsat(const nir_def *def);
 bool nir_def_all_uses_ignore_sign_bit(const nir_def *def);
 
+static inline int
+nir_def_first_component_read(nir_def *def)
+{
+    return (int)ffs(nir_def_components_read(def)) - 1;
+}
+
 static inline int
 nir_def_last_component_read(nir_def *def)
 {