From 3cf84263ec2648ea88f8d4e3570cb19403a241af Mon Sep 17 00:00:00 2001
From: Weixie Cui <cuiweixie@gmail.com>
Date: Wed, 29 Apr 2026 15:24:01 +0000
Subject: [PATCH] runtime: prune tombstones before rehash in fast32 pointer-key
 insert

Change-Id: I08ade4ff3622007cf9e0e3b7a3cd0b9ad1e462ed
GitHub-Last-Rev: abf4ca52b327bdcb1ebae1157a039ebd01b36878
GitHub-Pull-Request: golang/go#79030
Reviewed-on: https://go-review.googlesource.com/c/go/+/772060
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---
 src/internal/runtime/maps/runtime_fast32.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/internal/runtime/maps/runtime_fast32.go b/src/internal/runtime/maps/runtime_fast32.go
index c756314897..615c739423 100644
--- a/src/internal/runtime/maps/runtime_fast32.go
+++ b/src/internal/runtime/maps/runtime_fast32.go
@@ -397,6 +397,10 @@ outer:
 				t.growthLeft++ // will be decremented below to become a no-op.
 			}
 
+			if t.growthLeft == 0 {
+				t.pruneTombstones(typ, m)
+			}
+
 			// If there is room left to grow, just insert the new entry.
 			if t.growthLeft > 0 {
 				slotKey := g.key(typ, i)