From 8ed8d370880b5c4e7bbf52b50791710a9f4f834b Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo@fhahn.com>
Date: Sat, 13 Nov 2021 09:39:14 +0000
Subject: [PATCH] [SCEV] Update SCEVLoopGuardRewriter to hold reference to map.
 (NFC)

SCEVLoopGuardRewriter doesn't need to copy the rewrite map. It can just
hold a const reference instead, to avoid an unnecessary copy.
---
 llvm/lib/Analysis/ScalarEvolution.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index d7effde..5bdbe40 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -13696,7 +13696,7 @@ ScalarEvolution::computeSymbolicMaxBackedgeTakenCount(const Loop *L) {
 ///
 /// At the moment only rewriting SCEVUnknown is supported.
 class SCEVLoopGuardRewriter : public SCEVRewriteVisitor<SCEVLoopGuardRewriter> {
-  DenseMap<const SCEV *, const SCEV *> Map;
+  const DenseMap<const SCEV *, const SCEV *> &Map;
 
 public:
   SCEVLoopGuardRewriter(ScalarEvolution &SE,
-- 
2.7.4