From 5a4cbea3120f5e921849bd89c0b43096ef65787f Mon Sep 17 00:00:00 2001
From: Jim Grosbach <grosbach@apple.com>
Date: Wed, 1 Sep 2010 21:34:41 +0000
Subject: cleanup per feedback. use a helper function for getting the first
 non-reserved physical register in a register class. Make sure to assert if
 the register class is empty.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112743 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/RegAllocLinearScan.cpp | 31 ++++++++++++++-----------------
 1 file changed, 14 insertions(+), 17 deletions(-)

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

diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index a667f97a4e..23ec2d7676 100644
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -336,6 +336,17 @@ namespace {
                             SmallVector<unsigned, 256> &inactiveCounts,
                             bool SkipDGRegs);
 
+    /// getFirstNonReservedPhysReg - return the first non-reserved physical
+    /// register in the register class.
+    unsigned getFirstNonReservedPhysReg(const TargetRegisterClass *RC) {
+        TargetRegisterClass::iterator aoe = RC->allocation_order_end(*mf_);
+        TargetRegisterClass::iterator i = RC->allocation_order_begin(*mf_);
+        while (i != aoe && reservedRegs_.test(*i))
+          ++i;
+        assert(i != aoe && "All registers reserved?!");
+        return *i;
+      }
+
     void ComputeRelatedRegClasses();
 
     template <typename ItTy>
@@ -951,14 +962,8 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) {
   const TargetRegisterClass *RC = mri_->getRegClass(cur->reg);
   if (cur->empty()) {
     unsigned physReg = vrm_->getRegAllocPref(cur->reg);
-    if (!physReg) {
-      TargetRegisterClass::iterator aoe = RC->allocation_order_end(*mf_);
-      TargetRegisterClass::iterator i = RC->allocation_order_begin(*mf_);
-      while (reservedRegs_.test(*i) && i != aoe)
-        ++i;
-      assert(i != aoe && "All registers reserved?!");
-      physReg = *i;
-    }
+    if (!physReg)
+      physReg = getFirstNonReservedPhysReg(RC);
     DEBUG(dbgs() <<  tri_->getName(physReg) << '\n');
     // Note the register is not really in use.
     vrm_->assignVirt2Phys(cur->reg, physReg);
@@ -1168,15 +1173,7 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur) {
   minWeight = RegsWeights[0].second;
   if (minWeight == HUGE_VALF) {
     // All registers must have inf weight. Just grab one!
-    if (BestPhysReg == 0) {
-      TargetRegisterClass::iterator aoe = RC->allocation_order_end(*mf_);
-      TargetRegisterClass::iterator i = RC->allocation_order_begin(*mf_);
-      while (reservedRegs_.test(*i) && i != aoe)
-        ++i;
-      assert(i != aoe && "All registers reserved?!");
-      minReg = *i;
-    } else
-      minReg = BestPhysReg;
+    minReg = BestPhysReg ? BestPhysReg : getFirstNonReservedPhysReg(RC);
     if (cur->weight == HUGE_VALF ||
         li_->getApproximateInstructionCount(*cur) == 0) {
       // Spill a physical register around defs and uses.
-- 
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