From 2ab78937dd29fbc299ac434f962a5ff41002cc43 Mon Sep 17 00:00:00 2001
From: Rahul Prabhu <cupertinorp@gmail.com>
Date: Sun, 21 Jan 2024 22:45:03 +0530
Subject: [PATCH] Don't assume a write if an operand is not in function
 parameters

Liveness assumes that if the operand is not in the parameters of
a function call it is being written to, resulting in pointless memcpies.
---
 src/Liveness.zig | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Liveness.zig b/src/Liveness.zig
index 56b70be317..6227da3ede 100644
--- a/src/Liveness.zig
+++ b/src/Liveness.zig
@@ -489,7 +489,7 @@ pub fn categorizeOperand(
                 for (args, 0..) |arg, i| {
                     if (arg == operand_ref) return matchOperandSmallIndex(l, inst, @as(OperandInt, @intCast(i + 1)), .write);
                 }
-                return .write;
+                return .none;
             }
             var bt = l.iterateBigTomb(inst);
             if (bt.feed()) {
@@ -504,7 +504,7 @@ pub fn categorizeOperand(
                     if (arg == operand_ref) return .write;
                 }
             }
-            return .write;
+            return .none;
         },
         .select => {
             const pl_op = air_datas[@intFromEnum(inst)].pl_op;