1 files changed, 43 insertions, 28 deletions

diff --git a/llvm/lib/CodeGen/RegAllocGreedy.cpp b/llvm/lib/CodeGen/RegAllocGreedy.cpp
index 8e6cf3e..7fe13a3 100644
--- a/llvm/lib/CodeGen/RegAllocGreedy.cpp
+++ b/llvm/lib/CodeGen/RegAllocGreedy.cpp
@@ -1406,8 +1406,24 @@ bool RAGreedy::trySplitAroundHintReg(MCPhysReg Hint,
       continue;
 
     // Check if VirtReg interferes with OtherReg after this COPY instruction.
-    if (!IsDef && VirtReg.liveAt(LIS->getInstructionIndex(Instr).getRegSlot()))
-      continue;
+    if (Opnd.readsReg()) {
+      SlotIndex Index = LIS->getInstructionIndex(Instr).getRegSlot();
+
+      if (SubReg) {
+        LaneBitmask Mask = TRI->getSubRegIndexLaneMask(SubReg);
+        if (IsDef)
+          Mask = ~Mask;
+
+        if (any_of(VirtReg.subranges(), [=](const LiveInterval::SubRange &S) {
+              return (S.LaneMask & Mask).any() && S.liveAt(Index);
+            })) {
+          continue;
+        }
+      } else {
+        if (VirtReg.liveAt(Index))
+          continue;
+      }
+    }
 
     MCRegister OtherPhysReg =
         OtherReg.isPhysical() ? OtherReg.asMCReg() : VRM->getPhys(OtherReg);
@@ -2419,25 +2435,28 @@ void RAGreedy::collectHintInfo(Register Reg, HintsInfo &Out) {
     unsigned SubReg = Opnd.getSubReg();
 
     // Get the current assignment.
-    MCRegister OtherPhysReg =
-        OtherReg.isPhysical() ? OtherReg.asMCReg() : VRM->getPhys(OtherReg);
-    if (OtherSubReg) {
-      if (OtherReg.isPhysical()) {
-        MCRegister Tuple =
-            TRI->getMatchingSuperReg(OtherPhysReg, OtherSubReg, RC);
-        if (!Tuple)
-          continue;
-        OtherPhysReg = Tuple;
-      } else {
-        // TODO: There should be a hinting mechanism for subregisters
-        if (SubReg != OtherSubReg)
-          continue;
-      }
+    MCRegister OtherPhysReg;
+    if (OtherReg.isPhysical()) {
+      if (OtherSubReg)
+        OtherPhysReg = TRI->getMatchingSuperReg(OtherReg, OtherSubReg, RC);
+      else if (SubReg)
+        OtherPhysReg = TRI->getMatchingSuperReg(OtherReg, SubReg, RC);
+      else
+        OtherPhysReg = OtherReg;
+    } else {
+      OtherPhysReg = VRM->getPhys(OtherReg);
+      // TODO: Should find matching superregister, but applying this in the
+      // non-hint case currently causes regressions
+
+      if (SubReg && OtherSubReg && SubReg != OtherSubReg)
+        continue;
     }
 
     // Push the collected information.
-    Out.push_back(HintInfo(MBFI->getBlockFreq(Instr.getParent()), OtherReg,
-                           OtherPhysReg));
+    if (OtherPhysReg) {
+      Out.push_back(HintInfo(MBFI->getBlockFreq(Instr.getParent()), OtherReg,
+                             OtherPhysReg));
+    }
   }
 }
 
@@ -2466,15 +2485,13 @@ void RAGreedy::tryHintRecoloring(const LiveInterval &VirtReg) {
   // We have a broken hint, check if it is possible to fix it by
   // reusing PhysReg for the copy-related live-ranges. Indeed, we evicted
   // some register and PhysReg may be available for the other live-ranges.
-  SmallSet<Register, 4> Visited;
-  SmallVector<Register, 2> RecoloringCandidates;
   HintsInfo Info;
   Register Reg = VirtReg.reg();
   MCRegister PhysReg = VRM->getPhys(Reg);
   // Start the recoloring algorithm from the input live-interval, then
   // it will propagate to the ones that are copy-related with it.
-  Visited.insert(Reg);
-  RecoloringCandidates.push_back(Reg);
+  SmallSet<Register, 4> Visited = {Reg};
+  SmallVector<Register, 2> RecoloringCandidates = {Reg};
 
   LLVM_DEBUG(dbgs() << "Trying to reconcile hints for: " << printReg(Reg, TRI)
                     << '(' << printReg(PhysReg, TRI) << ")\n");
@@ -2482,12 +2499,10 @@ void RAGreedy::tryHintRecoloring(const LiveInterval &VirtReg) {
   do {
     Reg = RecoloringCandidates.pop_back_val();
 
-    // We cannot recolor physical register.
-    if (Reg.isPhysical())
-      continue;
+    MCRegister CurrPhys = VRM->getPhys(Reg);
 
     // This may be a skipped register.
-    if (!VRM->hasPhys(Reg)) {
+    if (!CurrPhys) {
       assert(!shouldAllocateRegister(Reg) &&
              "We have an unallocated variable which should have been handled");
       continue;
@@ -2496,7 +2511,6 @@ void RAGreedy::tryHintRecoloring(const LiveInterval &VirtReg) {
     // Get the live interval mapped with this virtual register to be able
     // to check for the interference with the new color.
     LiveInterval &LI = LIS->getInterval(Reg);
-    MCRegister CurrPhys = VRM->getPhys(Reg);
     // Check that the new color matches the register class constraints and
     // that it is free for this live range.
     if (CurrPhys != PhysReg && (!MRI->getRegClass(Reg)->contains(PhysReg) ||
@@ -2533,7 +2547,8 @@ void RAGreedy::tryHintRecoloring(const LiveInterval &VirtReg) {
     // Push all copy-related live-ranges to keep reconciling the broken
     // hints.
     for (const HintInfo &HI : Info) {
-      if (Visited.insert(HI.Reg).second)
+      // We cannot recolor physical register.
+      if (HI.Reg.isVirtual() && Visited.insert(HI.Reg).second)
         RecoloringCandidates.push_back(HI.Reg);
     }
   } while (!RecoloringCandidates.empty());