From 8c42f48d023c4b9164b3c39ad0513b53f1cc1e91 Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Thu, 4 Nov 2010 00:32:32 +0000
Subject: [PATCH] Disable fancy splitting during spilling unless
 -extra-spiller-splits is given.

This way, InlineSpiller does the same amount of splitting as the standard
spiller. Splitting should really be guided by the register allocator, and
doesn't belong in the spiller at all.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118216 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/InlineSpiller.cpp | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index 0e157acfdcf..ee30a1512a2 100644
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -35,6 +35,10 @@ using namespace llvm;
 static cl::opt<bool>
 VerifySpills("verify-spills", cl::desc("Verify after each spill/split"));
 
+static cl::opt<bool>
+ExtraSpillerSplits("extra-spiller-splits",
+                   cl::desc("Enable additional splitting during splitting"));
+
 namespace {
 class InlineSpiller : public Spiller {
   MachineFunctionPass &pass_;
@@ -116,10 +120,13 @@ bool InlineSpiller::split() {
   splitAnalysis_.analyze(&edit_->getParent());
 
   // Try splitting around loops.
-  if (const MachineLoop *loop = splitAnalysis_.getBestSplitLoop()) {
-    SplitEditor(splitAnalysis_, lis_, vrm_, mdt_, *edit_)
-      .splitAroundLoop(loop);
-    return true;
+  if (ExtraSpillerSplits) {
+    const MachineLoop *loop = splitAnalysis_.getBestSplitLoop();
+    if (loop) {
+      SplitEditor(splitAnalysis_, lis_, vrm_, mdt_, *edit_)
+        .splitAroundLoop(loop);
+      return true;
+    }
   }
 
   // Try splitting into single block intervals.
@@ -131,10 +138,13 @@ bool InlineSpiller::split() {
   }
 
   // Try splitting inside a basic block.
-  if (const MachineBasicBlock *MBB = splitAnalysis_.getBlockForInsideSplit()) {
-    SplitEditor(splitAnalysis_, lis_, vrm_, mdt_, *edit_)
-      .splitInsideBlock(MBB);
-    return true;
+  if (ExtraSpillerSplits) {
+    const MachineBasicBlock *MBB = splitAnalysis_.getBlockForInsideSplit();
+    if (MBB){
+      SplitEditor(splitAnalysis_, lis_, vrm_, mdt_, *edit_)
+        .splitInsideBlock(MBB);
+      return true;
+    }
   }
 
   return false;