From fabffca0bd33e91c565ba4bf21980b00dc932ae8 Mon Sep 17 00:00:00 2001
From: Faith Ekstrand <faith.ekstrand@collabora.com>
Date: Mon, 15 Jun 2026 22:56:22 -0400
Subject: [PATCH] kraid/swizzle: Take a src_bytes param in
 Swizzle::bytes_read()

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/42274>
---
 src/panfrost/compiler/kraid/small_constants.rs |  2 +-
 src/panfrost/compiler/kraid/swizzle.rs         | 13 ++++++++++---
 src/panfrost/compiler/kraid/validate.rs        | 18 ++++++++++--------
 3 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/src/panfrost/compiler/kraid/small_constants.rs b/src/panfrost/compiler/kraid/small_constants.rs
index 4fa74749a8a..69047f36bfd 100644
--- a/src/panfrost/compiler/kraid/small_constants.rs
+++ b/src/panfrost/compiler/kraid/small_constants.rs
@@ -19,7 +19,7 @@ fn try_lower_src(src: &mut Src, sc_table: &[SmallConstant]) -> bool {
     };
     let imm32 = u32::from(imm32);
 
-    let imm_bytes_read = src.swizzle.bytes_read();
+    let imm_bytes_read = src.swizzle.bytes_read(4);
 
     if imm_bytes_read.count_ones() == 1 {
         let imm_byte = imm_bytes_read.trailing_zeros();
diff --git a/src/panfrost/compiler/kraid/swizzle.rs b/src/panfrost/compiler/kraid/swizzle.rs
index 1b6196449c6..0dd41694dff 100644
--- a/src/panfrost/compiler/kraid/swizzle.rs
+++ b/src/panfrost/compiler/kraid/swizzle.rs
@@ -644,16 +644,23 @@ impl Swizzle {
         Some(folded)
     }
 
-    pub fn bytes_read(&self) -> u8 {
+    pub fn bytes_read(&self, src_bytes: u8) -> u8 {
         let mut bytes = 0_u8;
-        if self.is_word_swizzle() {
+        if self.is_none() {
+            if src_bytes >= 8 {
+                bytes = 0xff;
+            } else {
+                bytes = !((!0_u8) << src_bytes);
+            }
+        } else if self.is_word_swizzle() {
+            debug_assert_eq!(src_bytes, 8);
             for i in 0..2 {
                 if let Some(w) = self.word(i).unwrap().word_idx() {
                     bytes |= 0xf << (w * 4);
                 }
             }
         } else {
-            for i in 0..4 {
+            for i in 0..src_bytes.min(4) {
                 if let Some(b) = self.byte(i).unwrap().byte_idx() {
                     bytes |= 1 << b;
                 }
diff --git a/src/panfrost/compiler/kraid/validate.rs b/src/panfrost/compiler/kraid/validate.rs
index 3eb9b808d24..7316df6fbe3 100644
--- a/src/panfrost/compiler/kraid/validate.rs
+++ b/src/panfrost/compiler/kraid/validate.rs
@@ -31,30 +31,32 @@ fn validate_instr(instr: &Instr, ssa_vals: &mut FxHashSet<SSAValue>) {
                     assert!(src.swizzle == Swizzle::NONE);
                 } else {
                     let src_ref_byte_mask = u8::MAX >> (8 - src_ref_bytes);
-                    assert!(src.swizzle.bytes_read() & !src_ref_byte_mask == 0);
+                    let swizzle_byte_mask =
+                        src.swizzle.bytes_read(src_ref_bytes);
+                    assert!(swizzle_byte_mask & !src_ref_byte_mask == 0);
                 }
             }
             SrcRef::Reg(reg) => match reg.range {
                 RegRange::Byte0 => {
-                    assert!(src.swizzle.bytes_read() & !0b0001 == 0);
+                    assert!(src.swizzle.bytes_read(4) & !0b0001 == 0);
                 }
                 RegRange::Byte1 => {
-                    assert!(src.swizzle.bytes_read() & !0b0010 == 0);
+                    assert!(src.swizzle.bytes_read(4) & !0b0010 == 0);
                 }
                 RegRange::Byte2 => {
-                    assert!(src.swizzle.bytes_read() & !0b0100 == 0);
+                    assert!(src.swizzle.bytes_read(4) & !0b0100 == 0);
                 }
                 RegRange::Byte3 => {
-                    assert!(src.swizzle.bytes_read() & !0b1000 == 0);
+                    assert!(src.swizzle.bytes_read(4) & !0b1000 == 0);
                 }
                 RegRange::Half0 => {
-                    assert!(src.swizzle.bytes_read() & !0b0011 == 0);
+                    assert!(src.swizzle.bytes_read(4) & !0b0011 == 0);
                 }
                 RegRange::Half1 => {
-                    assert!(src.swizzle.bytes_read() & !0b1100 == 0);
+                    assert!(src.swizzle.bytes_read(4) & !0b1100 == 0);
                 }
                 RegRange::Regs(n) => match n {
-                    1 => assert!(src.swizzle.bytes_read() & !0x0f == 0),
+                    1 => assert!(src.swizzle.bytes_read(n * 4) & !0x0f == 0),
                     2 => (), // Not much we can assert here
                     _ => assert!(src.swizzle == Swizzle::NONE),
                 },