From df30cf9e61e6586b45b74d1312bef1ee758ef94f Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Tue, 10 Aug 2010 00:02:26 +0000
Subject: Transpose the calculation of spill weights such that we are
 calculating one register at a time. This turns out to be slightly faster than
 iterating over instructions, but more importantly, it allows us to compute
 spill weights for new registers created after the spill weight pass has run.

Also compute the allocation hint at the same time as the spill weight. This
allows us to use the spill weight as a cost metric for copies, and choose the
most profitable hint if there is more than one possibility.

The new hints provide a very small (< 0.1%) but universal code size improvement.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110631 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SimpleRegisterCoalescing.cpp | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

(limited to 'lib/CodeGen/SimpleRegisterCoalescing.cpp')

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index fd6ffcecd1..1dcc674eed 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -1044,7 +1044,7 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
   if (CP.isPhys()) {
     DEBUG(dbgs() <<" with physreg %" << tri_->getName(CP.getDstReg()) << "\n");
     // Only coalesce to allocatable physreg.
-    if (!allocatableRegs_[CP.getDstReg()]) {
+    if (!li_->isAllocatable(CP.getDstReg())) {
       DEBUG(dbgs() << "\tRegister is an unallocatable physreg.\n");
       return false;  // Not coalescable.
     }
@@ -1093,7 +1093,6 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
     // happens.
     if (li_->hasInterval(CP.getDstReg()) &&
         li_->getInterval(CP.getDstReg()).ranges.size() > 1000) {
-      mri_->setRegAllocationHint(CP.getSrcReg(), 0, CP.getDstReg());
       ++numAborts;
       DEBUG(dbgs()
            << "\tPhysical register live interval too complicated, abort!\n");
@@ -1112,7 +1111,6 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
           ReMaterializeTrivialDef(JoinVInt, CP.getDstReg(), 0, CopyMI))
         return true;
 
-      mri_->setRegAllocationHint(CP.getSrcReg(), 0, CP.getDstReg());
       ++numAborts;
       DEBUG(dbgs() << "\tMay tie down a physical register, abort!\n");
       Again = true;  // May be possible to coalesce later.
@@ -1693,7 +1691,6 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) {
                << "********** Function: "
                << ((Value*)mf_->getFunction())->getName() << '\n');
 
-  allocatableRegs_ = tri_->getAllocatableSet(fn);
   for (TargetRegisterInfo::regclass_iterator I = tri_->regclass_begin(),
          E = tri_->regclass_end(); I != E; ++I)
     allocatableRCRegs_.insert(std::make_pair(*I,
-- 
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