3 files changed, 12 insertions, 7 deletions
diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
index 85d051cfdbe7..a8d40edd88d3 100644
--- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -1237,7 +1237,13 @@ void PEI::insertZeroCallUsedRegs(MachineFunction &MF) {
         if (!MO.isReg())
           continue;
 
-        for (MCPhysReg SReg : TRI.sub_and_superregs_inclusive(MO.getReg()))
+        MCRegister Reg = MO.getReg();
+
+        // This picks up sibling registers (e.q. %al -> %ah).
+        for (MCRegUnitIterator Unit(Reg, &TRI); Unit.isValid(); ++Unit)
+          RegsToZero.reset(*Unit);
+
+        for (MCPhysReg SReg : TRI.sub_and_superregs_inclusive(Reg))
           RegsToZero.reset(SReg);
       }
     }
diff --git a/llvm/lib/CodeGen/RegAllocFast.cpp b/llvm/lib/CodeGen/RegAllocFast.cpp
index 9e4e26f1392e..cb552f212fbb 100644
--- a/llvm/lib/CodeGen/RegAllocFast.cpp
+++ b/llvm/lib/CodeGen/RegAllocFast.cpp
@@ -443,6 +443,9 @@ void RegAllocFast::spill(MachineBasicBlock::iterator Before, Register VirtReg,
     SpilledOperandsMap[MO->getParent()].push_back(MO);
   for (auto MISpilledOperands : SpilledOperandsMap) {
     MachineInstr &DBG = *MISpilledOperands.first;
+    // We don't have enough support for tracking operands of DBG_VALUE_LISTs.
+    if (DBG.isDebugValueList())
+      continue;
     MachineInstr *NewDV = buildDbgValueForSpill(
         *MBB, Before, *MISpilledOperands.first, FI, MISpilledOperands.second);
     assert(NewDV->getParent() == MBB && "dangling parent pointer");
diff --git a/llvm/lib/CodeGen/TypePromotion.cpp b/llvm/lib/CodeGen/TypePromotion.cpp
index a63118067139..36e3c1245f1c 100644
--- a/llvm/lib/CodeGen/TypePromotion.cpp
+++ b/llvm/lib/CodeGen/TypePromotion.cpp
@@ -570,7 +570,6 @@ void IRPromoter::Cleanup() {
   LLVM_DEBUG(dbgs() << "IR Promotion: Cleanup..\n");
   // Some zexts will now have become redundant, along with their trunc
   // operands, so remove them.
-  // Some zexts need to be replaced with truncate if src bitwidth is larger.
   for (auto *V : Visited) {
     if (!isa<ZExtInst>(V))
       continue;
@@ -585,11 +584,6 @@ void IRPromoter::Cleanup() {
                         << "\n");
       ReplaceAllUsersOfWith(ZExt, Src);
       continue;
-    } else if (ZExt->getSrcTy()->getScalarSizeInBits() > PromotedWidth) {
-      IRBuilder<> Builder{ZExt};
-      Value *Trunc = Builder.CreateTrunc(Src, ZExt->getDestTy());
-      ReplaceAllUsersOfWith(ZExt, Trunc);
-      continue;
     }
 
     // We've inserted a trunc for a zext sink, but we already know that the
@@ -626,6 +620,8 @@ void IRPromoter::ConvertTruncs() {
     ConstantInt *Mask =
         ConstantInt::get(SrcTy, APInt::getMaxValue(NumBits).getZExtValue());
     Value *Masked = Builder.CreateAnd(Trunc->getOperand(0), Mask);
+    if (SrcTy != ExtTy)
+      Masked = Builder.CreateTrunc(Masked, ExtTy);
 
     if (auto *I = dyn_cast<Instruction>(Masked))
       NewInsts.insert(I);