kraid: Add a FlowCtrl struct

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41841>

src/panfrost/compiler/kraid/flow.rs

@@ -0,0 +1,122 @@
+// Copyright © 2026 Collabora, Ltd.
+// SPDX-License-Identifier: MIT
+
+use crate::bitview::*;
+
+#[repr(u8)]
+#[derive(Clone, Copy, Eq, Hash, PartialEq)]
+pub enum FlowWaitBit {
+    Slot0 = 0,
+    Slot1 = 1,
+    Slot2 = 2,
+    Resource = 5,
+    ZS = 6,
+    Barrier = 7,
+}
+
+#[repr(u8)]
+#[derive(Clone, Copy, Eq, Hash, PartialEq)]
+enum FlowCtrlBit {
+    MsgSlotBit0 = 0,
+    MsgSlotBit1 = 1,
+    Reconverge,
+    Discard,
+    EndShader,
+}
+
+#[derive(Clone, Copy, Default, Eq, Hash, PartialEq)]
+pub struct FlowCtrl {
+    pub wait: u8,
+    ctrl: u8,
+}
+
+impl FlowCtrl {
+    pub const NONE: FlowCtrl = FlowCtrl { wait: 0, ctrl: 0 };
+
+    fn get_ctrl_bit(&self, bit: FlowCtrlBit) -> bool {
+        BitView::new(&self.ctrl).get_bit(bit as usize)
+    }
+
+    fn set_ctrl_bit(&mut self, bit: FlowCtrlBit) {
+        BitMutView::new(&mut self.ctrl).set_bit(bit as usize, true);
+    }
+
+    fn take_ctrl_bit(&mut self, bit: FlowCtrlBit) -> bool {
+        let mut bv = BitMutView::new(&mut self.ctrl);
+        let val = bv.get_bit(bit as usize);
+        bv.set_bit(bit as usize, false);
+        val
+    }
+
+    pub fn get_msg_slot_idx(&self) -> Option<u8> {
+        let slot = BitView::new(&self.ctrl).get_bit_range_u64(0..2) as u8;
+        if slot > 0 {
+            Some((slot - 1) as u8)
+        } else {
+            None
+        }
+    }
+
+    pub fn set_msg_slot_idx(&mut self, slot_idx: u8) {
+        assert!(slot_idx < 3);
+        let slot = slot_idx + 1;
+        BitMutView::new(&mut self.ctrl).set_field(0..2, slot);
+    }
+
+    pub fn take_msg_slot_idx(&mut self) -> Option<u8> {
+        let val = self.get_msg_slot_idx();
+        BitMutView::new(&mut self.ctrl).set_field(0..2, 0_u8);
+        val
+    }
+
+    pub fn get_reconverge(&self) -> bool {
+        self.get_ctrl_bit(FlowCtrlBit::Reconverge)
+    }
+
+    pub fn set_reconverge(&mut self) {
+        self.set_ctrl_bit(FlowCtrlBit::Reconverge)
+    }
+
+    pub fn take_reconverge(&mut self) -> bool {
+        self.take_ctrl_bit(FlowCtrlBit::Reconverge)
+    }
+
+    pub fn get_discard(&self) -> bool {
+        self.get_ctrl_bit(FlowCtrlBit::Discard)
+    }
+
+    pub fn set_discard(&mut self) {
+        self.set_ctrl_bit(FlowCtrlBit::Discard)
+    }
+
+    pub fn take_discard(&mut self) -> bool {
+        self.take_ctrl_bit(FlowCtrlBit::Discard)
+    }
+
+    pub fn get_end_shader(&self) -> bool {
+        self.get_ctrl_bit(FlowCtrlBit::EndShader)
+    }
+
+    pub fn set_end_shader(&mut self) {
+        self.set_ctrl_bit(FlowCtrlBit::EndShader)
+    }
+
+    pub fn take_end_shader(&mut self) -> bool {
+        self.take_ctrl_bit(FlowCtrlBit::EndShader)
+    }
+
+    pub fn get_wait_bit(&self, bit: FlowWaitBit) -> bool {
+        BitView::new(&self.wait).get_bit(bit as usize)
+    }
+
+    pub fn set_wait_bit(&mut self, bit: FlowWaitBit) {
+        BitMutView::new(&mut self.wait).set_bit(bit as usize, true);
+    }
+
+    pub fn take_wait_bit(&mut self, bit: FlowWaitBit) -> bool {
+        let mut bv = BitMutView::new(&mut self.wait);
+        let val = bv.get_bit(bit as usize);
+        bv.set_bit(bit as usize, false);
+        val
+    }
+}

src/panfrost/compiler/kraid/ir.rs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: MIT
 
 pub use crate::data_type::DataType;
+pub use crate::flow::FlowCtrl;
 pub use crate::model::Model;
 pub use crate::ops::Op;
 use crate::ssa_value::SSAValueAllocator;
@@ -507,6 +508,7 @@ pub trait Opcode:
 #[derive(Clone)]
 pub struct Instr {
     pub op: Op,
+    pub flow: FlowCtrl,
 }
 
 impl Deref for Instr {
@@ -527,7 +529,10 @@ impl<T: Into<Op>> From<T> for Instr {
     fn from(op: T) -> Instr {
         let op = op.into();
         assert!(op.is_valid_variant());
-        Instr { op }
+        Instr {
+            op,
+            flow: Default::default(),
+        }
     }
 }
 

src/panfrost/compiler/kraid/lib.rs

@@ -5,6 +5,7 @@ mod bitview;
 mod builder;
 mod compile;
 mod data_type;
+mod flow;
 mod ir;
 mod model;
 mod nir;