From 4f85f747b06a3be1591b52c1f15ff6588b8e5764 Mon Sep 17 00:00:00 2001
From: Ben Gamari <ben@smart-cactus.org>
Date: Tue, 22 Nov 2022 20:23:19 -0500
Subject: rts: Ensure that global regs are never passed as fun call args

This is in general unsafe as they may be clobbered if they are mapped to
caller-saved machine registers. See Note [Register parameter passing].
---
 rts/HeapStackCheck.cmm | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/rts/HeapStackCheck.cmm b/rts/HeapStackCheck.cmm
index 49abbe934b..50b84a023c 100644
--- a/rts/HeapStackCheck.cmm
+++ b/rts/HeapStackCheck.cmm
@@ -569,7 +569,7 @@ stg_block_takemvar_finally
     W_ r1, r3;
     r1 = R1;
     r3 = R3;
-    unlockClosure(R3, stg_MVAR_DIRTY_info);
+    unlockClosure(r3, stg_MVAR_DIRTY_info);
     R1 = r1;
     R3 = r3;
     jump StgReturn [R1];
@@ -597,7 +597,7 @@ stg_block_readmvar_finally
     W_ r1, r3;
     r1 = R1;
     r3 = R3;
-    unlockClosure(R3, stg_MVAR_DIRTY_info);
+    unlockClosure(r3, stg_MVAR_DIRTY_info);
     R1 = r1;
     R3 = r3;
     jump StgReturn [R1];
@@ -625,7 +625,7 @@ stg_block_putmvar_finally
     W_ r1, r3;
     r1 = R1;
     r3 = R3;
-    unlockClosure(R3, stg_MVAR_DIRTY_info);
+    unlockClosure(r3, stg_MVAR_DIRTY_info);
     R1 = r1;
     R3 = r3;
     jump StgReturn [R1];
-- 
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