GlobalISel: disambiguate types when printing MIR

Some generic instructions have multiple types. While in theory these always be
discovered by inspecting the single definition of each generic vreg, in
practice those definitions won't always be local and traipsing through a big
function to find them will not be fun.

So this changes MIRPrinter to print out the type of uses as well as defs, if
they're known to be different or not known to be the same.

On the parsing side, we're a little more flexible: provided each register is
given a type in at least one place it's mentioned (and all types are
consistent) we accept the MIR. This doesn't introduce ambiguity but makes
writing tests manually a bit less painful.

llvm-svn: 281204

4 files changed, 56 insertions, 19 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 696ba48e97c..2147651c4ef 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -877,7 +877,7 @@ bool MIParser::parseSubRegisterIndex(unsigned &SubReg) {
 
 bool MIParser::parseRegisterTiedDefIndex(unsigned &TiedDefIdx) {
   if (!consumeIfPresent(MIToken::kw_tied_def))
-    return error("expected 'tied-def' after '('");
+    return true;
   if (Token.isNot(MIToken::IntegerLiteral))
     return error("expected an integer literal after 'tied-def'");
   if (getUnsigned(TiedDefIdx))
@@ -957,16 +957,28 @@ bool MIParser::parseRegisterOperand(MachineOperand &Dest,
     if (!TargetRegisterInfo::isVirtualRegister(Reg))
       return error("subregister index expects a virtual register");
   }
+  MachineRegisterInfo &MRI = MF.getRegInfo();
   if ((Flags & RegState::Define) == 0) {
     if (consumeIfPresent(MIToken::lparen)) {
       unsigned Idx;
-      if (parseRegisterTiedDefIndex(Idx))
-        return true;
-      TiedDefIdx = Idx;
+      if (!parseRegisterTiedDefIndex(Idx))
+        TiedDefIdx = Idx;
+      else {
+        // Try a redundant low-level type.
+        LLT Ty;
+        if (parseLowLevelType(Token.location(), Ty))
+          return error("expected tied-def or low-level type after '('");
+
+        if (expectAndConsume(MIToken::rparen))
+          return true;
+
+        if (MRI.getType(Reg).isValid() && MRI.getType(Reg) != Ty)
+          return error("inconsistent type for generic virtual register");
+
+        MRI.setType(Reg, Ty);
+      }
     }
   } else if (consumeIfPresent(MIToken::lparen)) {
-    MachineRegisterInfo &MRI = MF.getRegInfo();
-
     // Virtual registers may have a size with GlobalISel.
     if (!TargetRegisterInfo::isVirtualRegister(Reg))
       return error("unexpected size on physical register");
@@ -980,6 +992,9 @@ bool MIParser::parseRegisterOperand(MachineOperand &Dest,
     if (expectAndConsume(MIToken::rparen))
       return true;
 
+    if (MRI.getType(Reg).isValid() && MRI.getType(Reg) != Ty)
+      return error("inconsistent type for generic virtual register");
+
     MRI.setType(Reg, Ty);
   } else if (PFS.GenericVRegs.count(Reg)) {
     // Generic virtual registers must have a size.
diff --git a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
index e7fdcc0afd8..104d7d18812 100644
--- a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
@@ -415,7 +415,7 @@ bool MIRParserImpl::initializeRegisterInfo(PerFunctionMIParsingState &PFS,
     if (StringRef(VReg.Class.Value).equals("_")) {
       // This is a generic virtual register.
       // The size will be set appropriately when we reach the definition.
-      Reg = RegInfo.createGenericVirtualRegister(LLT::scalar(1));
+      Reg = RegInfo.createGenericVirtualRegister(LLT{});
       PFS.GenericVRegs.insert(Reg);
     } else {
       const auto *RC = getRegClass(MF, VReg.Class.Value);
@@ -428,7 +428,7 @@ bool MIRParserImpl::initializeRegisterInfo(PerFunctionMIParsingState &PFS,
               VReg.Class.SourceRange.Start,
               Twine("use of undefined register class or register bank '") +
                   VReg.Class.Value + "'");
-        Reg = RegInfo.createGenericVirtualRegister(LLT::scalar(1));
+        Reg = RegInfo.createGenericVirtualRegister(LLT{});
         RegInfo.setRegBank(Reg, *RegBank);
         PFS.GenericVRegs.insert(Reg);
       }
diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index e293a0743eb..11d84d7c350 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -14,6 +14,7 @@
 
 #include "MIRPrinter.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallBitVector.h"
 #include "llvm/CodeGen/GlobalISel/RegisterBank.h"
 #include "llvm/CodeGen/MIRYamlMapping.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
@@ -123,7 +124,7 @@ public:
   void printTargetFlags(const MachineOperand &Op);
   void print(const MachineOperand &Op, const TargetRegisterInfo *TRI,
              unsigned I, bool ShouldPrintRegisterTies,
-             const MachineRegisterInfo *MRI = nullptr, bool IsDef = false);
+             LLT TypeToPrint, bool IsDef = false);
   void print(const MachineMemOperand &Op);
 
   void print(const MCCFIInstruction &CFI, const TargetRegisterInfo *TRI);
@@ -223,7 +224,7 @@ void MIRPrinter::convert(yaml::MachineFunction &MF,
       VReg.Class = StringRef(RegInfo.getRegBankOrNull(Reg)->getName()).lower();
     else {
       VReg.Class = std::string("_");
-      assert(RegInfo.getType(Reg).isValid() &&
+      assert((RegInfo.def_empty(Reg) || RegInfo.getType(Reg).isValid()) &&
              "Generic registers must have a valid type");
     }
     unsigned PreferredReg = RegInfo.getSimpleHint(Reg);
@@ -542,6 +543,27 @@ static bool hasComplexRegisterTies(const MachineInstr &MI) {
   return false;
 }
 
+static LLT getTypeToPrint(const MachineInstr &MI, unsigned OpIdx,
+                          SmallBitVector &PrintedTypes,
+                          const MachineRegisterInfo &MRI) {
+  const MachineOperand &Op = MI.getOperand(OpIdx);
+  if (!Op.isReg())
+    return LLT{};
+
+  if (MI.isVariadic() || OpIdx >= MI.getNumExplicitOperands())
+    return MRI.getType(Op.getReg());
+
+  auto &OpInfo = MI.getDesc().OpInfo[OpIdx];
+  if (!OpInfo.isGenericType())
+    return MRI.getType(Op.getReg());
+
+  if (PrintedTypes[OpInfo.getGenericTypeIndex()])
+    return LLT{};
+
+  PrintedTypes.set(OpInfo.getGenericTypeIndex());
+  return MRI.getType(Op.getReg());
+}
+
 void MIPrinter::print(const MachineInstr &MI) {
   const auto *MF = MI.getParent()->getParent();
   const auto &MRI = MF->getRegInfo();
@@ -553,6 +575,7 @@ void MIPrinter::print(const MachineInstr &MI) {
   if (MI.isCFIInstruction())
     assert(MI.getNumOperands() == 1 && "Expected 1 operand in CFI instruction");
 
+  SmallBitVector PrintedTypes(8);
   bool ShouldPrintRegisterTies = hasComplexRegisterTies(MI);
   unsigned I = 0, E = MI.getNumOperands();
   for (; I < E && MI.getOperand(I).isReg() && MI.getOperand(I).isDef() &&
@@ -560,7 +583,8 @@ void MIPrinter::print(const MachineInstr &MI) {
        ++I) {
     if (I)
       OS << ", ";
-    print(MI.getOperand(I), TRI, I, ShouldPrintRegisterTies, &MRI,
+    print(MI.getOperand(I), TRI, I, ShouldPrintRegisterTies,
+          getTypeToPrint(MI, I, PrintedTypes, MRI),
           /*IsDef=*/true);
   }
 
@@ -576,7 +600,8 @@ void MIPrinter::print(const MachineInstr &MI) {
   for (; I < E; ++I) {
     if (NeedComma)
       OS << ", ";
-    print(MI.getOperand(I), TRI, I, ShouldPrintRegisterTies);
+    print(MI.getOperand(I), TRI, I, ShouldPrintRegisterTies,
+          getTypeToPrint(MI, I, PrintedTypes, MRI));
     NeedComma = true;
   }
 
@@ -748,8 +773,8 @@ static const char *getTargetIndexName(const MachineFunction &MF, int Index) {
 }
 
 void MIPrinter::print(const MachineOperand &Op, const TargetRegisterInfo *TRI,
-                      unsigned I, bool ShouldPrintRegisterTies,
-                      const MachineRegisterInfo *MRI, bool IsDef) {
+                      unsigned I, bool ShouldPrintRegisterTies, LLT TypeToPrint,
+                      bool IsDef) {
   printTargetFlags(Op);
   switch (Op.getType()) {
   case MachineOperand::MO_Register:
@@ -776,9 +801,8 @@ void MIPrinter::print(const MachineOperand &Op, const TargetRegisterInfo *TRI,
       OS << '.' << TRI->getSubRegIndexName(Op.getSubReg());
     if (ShouldPrintRegisterTies && Op.isTied() && !Op.isDef())
       OS << "(tied-def " << Op.getParent()->findTiedOperandIdx(I) << ")";
-    assert((!IsDef || MRI) && "for IsDef, MRI must be provided");
-    if (IsDef && MRI->getType(Op.getReg()).isValid())
-      OS << '(' << MRI->getType(Op.getReg()) << ')';
+    if (TypeToPrint.isValid())
+      OS << '(' << TypeToPrint << ')';
     break;
   case MachineOperand::MO_Immediate:
     OS << Op.getImm();
diff --git a/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
index a16211cfa2b..ca89a1ff7bc 100644
--- a/llvm/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
@@ -126,8 +126,6 @@ void MachineRegisterInfo::setType(unsigned VReg, LLT Ty) {
 
 unsigned
 MachineRegisterInfo::createGenericVirtualRegister(LLT Ty) {
-  assert(Ty.isValid() && "Cannot create empty virtual register");
-
   // New virtual register number.
   unsigned Reg = TargetRegisterInfo::index2VirtReg(getNumVirtRegs());
   VRegInfo.grow(Reg);