From 819bf7120acf78a2ad2c1feafdd944ec29fffd12 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Fri, 9 Jun 2023 09:43:06 +1000
Subject: [PATCH] Don't merge CGUs in incremental builds.

---
 compiler/rustc_monomorphize/src/partitioning.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_monomorphize/src/partitioning.rs b/compiler/rustc_monomorphize/src/partitioning.rs
index 79fcd62bc6206..f6f7a63fd3537 100644
--- a/compiler/rustc_monomorphize/src/partitioning.rs
+++ b/compiler/rustc_monomorphize/src/partitioning.rs
@@ -161,10 +161,11 @@ where
 
     debug_dump(tcx, "INITIAL PARTITIONING", &codegen_units);
 
+    // njn: update comment
     // Merge until we have at most `max_cgu_count` codegen units.
     // `merge_codegen_units` is responsible for updating the CGU size
     // estimates.
-    {
+    if cx.tcx.sess.opts.incremental.is_none() {
         let _prof_timer = tcx.prof.generic_activity("cgu_partitioning_merge_cgus");
         merge_codegen_units(cx, &mut codegen_units);
         debug_dump(tcx, "POST MERGING", &codegen_units);