[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

3 files changed, 9 insertions, 6 deletions

diff --git a/llvm/include/llvm/CodeGen/MachineFunction.h b/llvm/include/llvm/CodeGen/MachineFunction.h
index 9eee7a56adb..7f4a3a8c2f9 100644
--- a/llvm/include/llvm/CodeGen/MachineFunction.h
+++ b/llvm/include/llvm/CodeGen/MachineFunction.h
@@ -796,6 +796,8 @@ public:
   /// Allocate and initialize a register mask with @p NumRegister bits.
   uint32_t *allocateRegMask();
 
+  ArrayRef<int> allocateShuffleMask(ArrayRef<int> Mask);
+
   /// Allocate and construct an extra info structure for a `MachineInstr`.
   ///
   /// This is allocated on the function's allocator and so lives the life of
diff --git a/llvm/include/llvm/CodeGen/MachineInstrBuilder.h b/llvm/include/llvm/CodeGen/MachineInstrBuilder.h
index 880d4829ac7..cabb9f1c97c 100644
--- a/llvm/include/llvm/CodeGen/MachineInstrBuilder.h
+++ b/llvm/include/llvm/CodeGen/MachineInstrBuilder.h
@@ -250,7 +250,7 @@ public:
     return *this;
   }
 
-  const MachineInstrBuilder &addShuffleMask(const Constant *Val) const {
+  const MachineInstrBuilder &addShuffleMask(ArrayRef<int> Val) const {
     MI->addOperand(*MF, MachineOperand::CreateShuffleMask(Val));
     return *this;
   }
diff --git a/llvm/include/llvm/CodeGen/MachineOperand.h b/llvm/include/llvm/CodeGen/MachineOperand.h
index 4222c03b023..9ba2b01cb4b 100644
--- a/llvm/include/llvm/CodeGen/MachineOperand.h
+++ b/llvm/include/llvm/CodeGen/MachineOperand.h
@@ -163,7 +163,8 @@ private:
   MachineInstr *ParentMI;
 
   /// Contents union - This contains the payload for the various operand types.
-  union {
+  union ContentsUnion {
+    ContentsUnion() {}
     MachineBasicBlock *MBB;  // For MO_MachineBasicBlock.
     const ConstantFP *CFP;   // For MO_FPImmediate.
     const ConstantInt *CI;   // For MO_CImmediate. Integers > 64bit.
@@ -174,7 +175,7 @@ private:
     unsigned CFIIndex;       // For MO_CFI.
     Intrinsic::ID IntrinsicID; // For MO_IntrinsicID.
     unsigned Pred;           // For MO_Predicate
-    const Constant *ShuffleMask; // For MO_ShuffleMask
+    ArrayRef<int> ShuffleMask; // For MO_ShuffleMask
 
     struct {                  // For MO_Register.
       // Register number is in SmallContents.RegNo.
@@ -587,7 +588,7 @@ public:
     return Contents.Pred;
   }
 
-  const Constant *getShuffleMask() const {
+  ArrayRef<int> getShuffleMask() const {
     assert(isShuffleMask() && "Wrong MachineOperand accessor");
     return Contents.ShuffleMask;
   }
@@ -915,9 +916,9 @@ public:
     return Op;
   }
 
-  static MachineOperand CreateShuffleMask(const Constant *C) {
+  static MachineOperand CreateShuffleMask(ArrayRef<int> Mask) {
     MachineOperand Op(MachineOperand::MO_ShuffleMask);
-    Op.Contents.ShuffleMask = C;
+    Op.Contents.ShuffleMask = Mask;
     return Op;
   }