[GlobalISel] Change representation of shuffle masks in MachineOperand.

We're planning to remove the shufflemask operand from ShuffleVectorInst
(D72467); fix GlobalISel so it doesn't depend on that Constant.

The change to prelegalizercombiner-shuffle-vector.mir happens because
the input contains a literal "-1" in the mask (so the parser/verifier
weren't really handling it properly). We now treat it as equivalent to
"undef" in all contexts.

Differential Revision: https://reviews.llvm.org/D72663

1 files changed, 6 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/MachineOperand.cpp b/llvm/lib/CodeGen/MachineOperand.cpp
index 0ea495bf0c0..7b8f0110092 100644
--- a/llvm/lib/CodeGen/MachineOperand.cpp
+++ b/llvm/lib/CodeGen/MachineOperand.cpp
@@ -930,13 +930,13 @@ void MachineOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
   }
   case MachineOperand::MO_ShuffleMask:
     OS << "shufflemask(";
-    const Constant* C = getShuffleMask();
-    const int NumElts = C->getType()->getVectorNumElements();
-
+    ArrayRef<int> Mask = getShuffleMask();
     StringRef Separator;
-    for (int I = 0; I != NumElts; ++I) {
-      OS << Separator;
-      C->getAggregateElement(I)->printAsOperand(OS, false, MST);
+    for (int Elt : Mask) {
+      if (Elt == -1)
+        OS << Separator << "undef";
+      else
+        OS << Separator << Elt;
       Separator = ", ";
     }