From f2cc77dca88075a1a90b90e036178041f233bf8a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Se=C3=A1n=20de=20B=C3=BArca?= <leftmostcat@gmail.com>
Date: Thu, 3 Apr 2025 18:28:07 -0700
Subject: [PATCH] nak: collapse extraneous conditional branches

v2: Revert collapsing of branches per review

Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34372>
---
 src/nouveau/compiler/nak/from_nir.rs           | 15 ++++++++-------
 src/nouveau/compiler/nak/liveness.rs           |  8 +++-----
 src/nouveau/compiler/nak/opt_uniform_instrs.rs |  6 +-----
 src/nouveau/compiler/nak/repair_ssa.rs         | 14 ++++++--------
 4 files changed, 18 insertions(+), 25 deletions(-)

diff --git a/src/nouveau/compiler/nak/from_nir.rs b/src/nouveau/compiler/nak/from_nir.rs
index 9b67c34850d..9025f18e028 100644
--- a/src/nouveau/compiler/nak/from_nir.rs
+++ b/src/nouveau/compiler/nak/from_nir.rs
@@ -3650,13 +3650,14 @@ impl<'a> ShaderFromNir<'a> {
             b.push_op(phi);
         }
 
-        if self.sm.sm() < 70 && nb.cf_node.prev().is_none() {
-            if let Some(_) = nb.parent().as_loop() {
-                b.push_op(OpPCnt {
-                    target: self.get_block_label(nb),
-                });
-                self.push_crs(nb, SyncType::Cont);
-            }
+        if self.sm.sm() < 70
+            && nb.cf_node.prev().is_none()
+            && nb.parent().as_loop().is_some()
+        {
+            b.push_op(OpPCnt {
+                target: self.get_block_label(nb),
+            });
+            self.push_crs(nb, SyncType::Cont);
         }
 
         let mut goto = None;
diff --git a/src/nouveau/compiler/nak/liveness.rs b/src/nouveau/compiler/nak/liveness.rs
index 349f2f84d2c..226504407c2 100644
--- a/src/nouveau/compiler/nak/liveness.rs
+++ b/src/nouveau/compiler/nak/liveness.rs
@@ -260,12 +260,10 @@ impl BlockLiveness for SimpleBlockLiveness {
     fn is_live_after_ip(&self, val: &SSAValue, ip: usize) -> bool {
         if self.live_out.get(val.idx().try_into().unwrap()) {
             true
+        } else if let Some(last_use_ip) = self.last_use.get(&val.idx()) {
+            *last_use_ip > ip
         } else {
-            if let Some(last_use_ip) = self.last_use.get(&val.idx()) {
-                *last_use_ip > ip
-            } else {
-                false
-            }
+            false
         }
     }
 
diff --git a/src/nouveau/compiler/nak/opt_uniform_instrs.rs b/src/nouveau/compiler/nak/opt_uniform_instrs.rs
index 2ef0b8dc9b4..72809f7dba7 100644
--- a/src/nouveau/compiler/nak/opt_uniform_instrs.rs
+++ b/src/nouveau/compiler/nak/opt_uniform_instrs.rs
@@ -20,11 +20,7 @@ fn should_lower_to_warp(
         }
     });
 
-    if num_non_uniform_srcs >= 2 {
-        return true;
-    }
-
-    return false;
+    num_non_uniform_srcs >= 2
 }
 
 fn propagate_r2ur(
diff --git a/src/nouveau/compiler/nak/repair_ssa.rs b/src/nouveau/compiler/nak/repair_ssa.rs
index 07fc1adc197..a95c80798bf 100644
--- a/src/nouveau/compiler/nak/repair_ssa.rs
+++ b/src/nouveau/compiler/nak/repair_ssa.rs
@@ -61,15 +61,13 @@ fn get_ssa_or_phi(
                 // This is a loop back-edge, add a phi just in case.  We'll
                 // remove it later if it's not needed
                 all_same = false;
-            } else {
-                if let Some(&p_ssa) = blocks[p_idx].defs.borrow().get(&ssa) {
-                    if *pred_ssa.get_or_insert(p_ssa) != p_ssa {
-                        all_same = false;
-                    }
-                } else {
-                    worklist.push(Reverse(p_idx));
-                    pushed_pred = true;
+            } else if let Some(&p_ssa) = blocks[p_idx].defs.borrow().get(&ssa) {
+                if *pred_ssa.get_or_insert(p_ssa) != p_ssa {
+                    all_same = false;
                 }
+            } else {
+                worklist.push(Reverse(p_idx));
+                pushed_pred = true;
             }
         }