GlobalISel: Change representation of shuffle masks

Currently shufflemasks get emitted as any other constant, and you end
up with a bunch of virtual registers of G_CONSTANT with a
G_BUILD_VECTOR. The AArch64 selector then asserts on anything that
doesn't fit this pattern. This isn't an ideal representation, and
should avoid legalization and have fewer opportunities for a
representational error.

Rather than invent a new shuffle mask operand type, similar to what
ShuffleVectorSDNode does, just track the original IR Constant mask
operand. I don't completely like the idea of adding another link to
the IR, but MIR is already quite dependent on IR constants already,
and this will allow sharing the shuffle mask utility functions with
the IR.

llvm-svn: 368704

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineOperand.cpp b/llvm/lib/CodeGen/MachineOperand.cpp
index a18ee52cc55..43081ccb329 100644
--- a/llvm/lib/CodeGen/MachineOperand.cpp
+++ b/llvm/lib/CodeGen/MachineOperand.cpp
@@ -333,6 +333,8 @@ bool MachineOperand::isIdenticalTo(const MachineOperand &Other) const {
     return getIntrinsicID() == Other.getIntrinsicID();
   case MachineOperand::MO_Predicate:
     return getPredicate() == Other.getPredicate();
+  case MachineOperand::MO_ShuffleMask:
+    return getShuffleMask() == Other.getShuffleMask();
   }
   llvm_unreachable("Invalid machine operand type");
 }
@@ -381,6 +383,8 @@ hash_code llvm::hash_value(const MachineOperand &MO) {
     return hash_combine(MO.getType(), MO.getTargetFlags(), MO.getIntrinsicID());
   case MachineOperand::MO_Predicate:
     return hash_combine(MO.getType(), MO.getTargetFlags(), MO.getPredicate());
+  case MachineOperand::MO_ShuffleMask:
+    return hash_combine(MO.getType(), MO.getTargetFlags(), MO.getShuffleMask());
   }
   llvm_unreachable("Invalid machine operand type");
 }
@@ -936,6 +940,20 @@ void MachineOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
        << CmpInst::getPredicateName(Pred) << ')';
     break;
   }
+  case MachineOperand::MO_ShuffleMask:
+    OS << "shufflemask(";
+    const Constant* C = getShuffleMask();
+    const int NumElts = C->getType()->getVectorNumElements();
+
+    StringRef Separator;
+    for (int I = 0; I != NumElts; ++I) {
+      OS << Separator;
+      C->getAggregateElement(I)->printAsOperand(OS, false, MST);
+      Separator = ", ";
+    }
+
+    OS << ')';
+    break;
   }
 }