From a835d8b533fd7ebba6d375602a4b5c981ac465fb Mon Sep 17 00:00:00 2001
From: Jonas Maebe <jonas@freepascal.org>
Date: Wed, 12 Oct 2022 22:50:25 +0200
Subject: [PATCH] rgobj: reduce compilation time of programs with long
 movelists

Reduces compilation time of webtbs/tw2242 for AArch64 with -O2 from
15 minutes to 10 seconds on my system.

from 15 minutes to 10 seconds
---
 compiler/rgobj.pas | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/compiler/rgobj.pas b/compiler/rgobj.pas
index ba426c82b3..c42ab8d227 100644
--- a/compiler/rgobj.pas
+++ b/compiler/rgobj.pas
@@ -1327,7 +1327,7 @@ unit rgobj;
     procedure trgobj.combine(u,v:Tsuperregister);
 
     var adj : Psuperregisterworklist;
-        i,n,p,q:cardinal;
+        original_u_count, i,n,p,q:cardinal;
         t : tsuperregister;
         searched:Tmoveins;
         found : boolean;
@@ -1365,6 +1365,7 @@ unit rgobj;
               sort_movelist(reginfo[u].movelist);
           if assigned(reginfo[v].movelist) then
             begin
+              original_u_count:=reginfo[u].movelist^.header.count;
               for n:=0 to reginfo[v].movelist^.header.count-1 do
                 begin
                   {Binary search the sorted part of the list.}
@@ -1385,7 +1386,9 @@ unit rgobj;
                       begin
                         {Linear search the unsorted part of the list.}
                         found:=false;
-                        for i:=header.sorted_until+1 to header.count-1 do
+                        { no need to search the instructions we've already added
+                          from v, we know we won't find a match there }
+                        for i:=header.sorted_until+1 to original_u_count-1 do
                           if searched.id=data[i].id then
                             begin
                               found:=true;