commit 67674e2685af8ab16292550becac15f7b17ea831
author Jakob Stoklund Olesen <stoklund@2pi.dk> Thu Jun 24 20:54:29 2010 +0000
committer Jakob Stoklund Olesen <stoklund@2pi.dk> Thu Jun 24 20:54:29 2010 +0000
tree a565994132e2ad60a8612349e7b26c807c89e054
parent 788184365a4a949eb83b0036045e6793bc6c20f0

Don't return a std::vector in the Spiller interface, but take a reference to a
vector instead. This avoids needless copying and allocation.

Add documentation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106788 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/Spiller.cpp

diff --git a/lib/CodeGen/Spiller.cpp b/lib/CodeGen/Spiller.cpp
index a7b2efe..23912c1 100644
--- a/lib/CodeGen/Spiller.cpp
+++ b/lib/CodeGen/Spiller.cpp
@@ -67,7 +67,8 @@
   /// Add spill ranges for every use/def of the live interval, inserting loads
   /// immediately before each use, and stores after each def. No folding or
   /// remat is attempted.
-  std::vector<LiveInterval*> trivialSpillEverywhere(LiveInterval *li) {
+  void trivialSpillEverywhere(LiveInterval *li,
+                              std::vector<LiveInterval*> &newIntervals) {
     DEBUG(dbgs() << "Spilling everywhere " << *li << "\n");
 
     assert(li->weight != HUGE_VALF &&
@@ -78,8 +79,6 @@
 
     DEBUG(dbgs() << "Trivial spill everywhere of reg" << li->reg << "\n");
 
-    std::vector<LiveInterval*> added;
-    
     const TargetRegisterClass *trc = mri->getRegClass(li->reg);
     unsigned ss = vrm->assignVirt2StackSlot(li->reg);
 
@@ -157,10 +156,8 @@
         newLI->addRange(LiveRange(beginIndex, storeIndex, storeVNI));
       }
 
-      added.push_back(newLI);
+      newIntervals.push_back(newLI);
     }
-
-    return added;
   }
 };
 
@@ -176,11 +173,12 @@
   TrivialSpiller(MachineFunction *mf, LiveIntervals *lis, VirtRegMap *vrm)
     : SpillerBase(mf, lis, vrm) {}
 
-  std::vector<LiveInterval*> spill(LiveInterval *li,
-                                   SmallVectorImpl<LiveInterval*> &spillIs,
-                                   SlotIndex*) {
+  void spill(LiveInterval *li,
+             std::vector<LiveInterval*> &newIntervals,
+             SmallVectorImpl<LiveInterval*> &,
+             SlotIndex*) {
     // Ignore spillIs - we don't use it.
-    return trivialSpillEverywhere(li);
+    trivialSpillEverywhere(li, newIntervals);
   }
 };
 
@@ -200,10 +198,13 @@
     : lis(lis), loopInfo(loopInfo), vrm(vrm) {}
 
   /// Falls back on LiveIntervals::addIntervalsForSpills.
-  std::vector<LiveInterval*> spill(LiveInterval *li,
-                                   SmallVectorImpl<LiveInterval*> &spillIs,
-                                   SlotIndex*) {
-    return lis->addIntervalsForSpills(*li, spillIs, loopInfo, *vrm);
+  void spill(LiveInterval *li,
+             std::vector<LiveInterval*> &newIntervals,
+             SmallVectorImpl<LiveInterval*> &spillIs,
+             SlotIndex*) {
+    std::vector<LiveInterval*> added =
+      lis->addIntervalsForSpills(*li, spillIs, loopInfo, *vrm);
+    newIntervals.insert(newIntervals.end(), added.begin(), added.end());
   }
 };
 
@@ -226,15 +227,14 @@
     tri = mf->getTarget().getRegisterInfo();
   }
 
-  std::vector<LiveInterval*> spill(LiveInterval *li,
-                                   SmallVectorImpl<LiveInterval*> &spillIs,
-                                   SlotIndex *earliestStart) {
-    
-    if (worthTryingToSplit(li)) {
-      return tryVNISplit(li, earliestStart);
-    }
-    // else
-    return StandardSpiller::spill(li, spillIs, earliestStart);
+  void spill(LiveInterval *li,
+             std::vector<LiveInterval*> &newIntervals,
+             SmallVectorImpl<LiveInterval*> &spillIs,
+             SlotIndex *earliestStart) {
+    if (worthTryingToSplit(li))
+      tryVNISplit(li, earliestStart);
+    else
+      StandardSpiller::spill(li, newIntervals, spillIs, earliestStart);
   }
 
 private: