From c425c51963854f592da4b9dbccef198959619cd6 Mon Sep 17 00:00:00 2001
From: Jonas Maebe <jonas@freepascal.org>
Date: Sat, 29 Jun 2019 12:17:49 +0000
Subject: [PATCH]   * simplify and optimize generated LLVM code for case
 statements

git-svn-id: trunk@42305 -
---
 .gitattributes             |  1 +
 compiler/llvm/llvmnode.pas |  2 +-
 compiler/llvm/nllvmset.pas | 53 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 compiler/llvm/nllvmset.pas

diff --git a/.gitattributes b/.gitattributes
index 5ab21c8878..6f44a9ab48 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -363,6 +363,7 @@ compiler/llvm/nllvminl.pas svneol=native#text/plain
 compiler/llvm/nllvmld.pas svneol=native#text/plain
 compiler/llvm/nllvmmat.pas svneol=native#text/plain
 compiler/llvm/nllvmmem.pas svneol=native#text/plain
+compiler/llvm/nllvmset.pas svneol=native#text/plain
 compiler/llvm/nllvmtcon.pas svneol=native#text/plain
 compiler/llvm/nllvmutil.pas svneol=native#text/plain
 compiler/llvm/rgllvm.pas svneol=native#text/plain
diff --git a/compiler/llvm/llvmnode.pas b/compiler/llvm/llvmnode.pas
index d305633544..729225c9e0 100644
--- a/compiler/llvm/llvmnode.pas
+++ b/compiler/llvm/llvmnode.pas
@@ -38,7 +38,7 @@ implementation
     ncgadd,ncgcal,ncgmat,ncginl,
     tgllvm,hlcgllvm,
     nllvmadd,nllvmbas,nllvmcal,nllvmcnv,nllvmcon,nllvmflw,nllvminl,nllvmld,
-    nllvmmat,nllvmmem,nllvmtcon,nllvmutil,
+    nllvmmat,nllvmmem,nllvmset,nllvmtcon,nllvmutil,
     llvmpara,llvmpi,
     symllvm,
     llvmcfi;
diff --git a/compiler/llvm/nllvmset.pas b/compiler/llvm/nllvmset.pas
new file mode 100644
index 0000000000..c3470625f9
--- /dev/null
+++ b/compiler/llvm/nllvmset.pas
@@ -0,0 +1,53 @@
+{
+    Copyright (c) 2019 by Jonas Maebe
+
+    Generate LLVM bytecode for set/case nodes
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ ****************************************************************************
+}
+unit nllvmset;
+
+{$i fpcdefs.inc}
+
+interface
+
+  uses
+    nset, ncgset;
+
+  type
+    tllvmcasenode = class(tcgcasenode)
+     protected
+      procedure genlinearlist(hp: pcaselabel); override;
+    end;
+
+
+implementation
+
+  procedure tllvmcasenode.genlinearlist(hp: pcaselabel);
+    begin
+      { genlinearlist constantly updates the case value in the register,
+        which causes tons of spilling with LLVM due to the need to bring
+        it back into SSA form. LLVM will recognise and optimise the linear
+        cmp list just as well (or even better), while the code that FPC
+        has to generate is much smaller (no spilling) }
+      genlinearcmplist(hp);
+    end;
+
+begin
+  ccasenode:=tllvmcasenode;
+end.
+