Commit d85821df authored by Sagar Jain's avatar Sagar Jain Committed by Alex Zinenko
Browse files

[MLIR] Added llvm.freeze 

This patch adds llvm.freeze & processes undef constants from LLVM IR.

Syntax:
LLVM IR
`<result> = freeze ty <val>`

MLIR LLVM Dialect:
`llvm.freeze val attr-dict : type`

Example:
LLVM IR: `%3 = freeze i32 5`
MLIR: `%6 = llvm.freeze %5 : !llvm.i32`

Differential Revision: https://reviews.llvm.org/D75329
parent 8c7c32b4

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

+5 −0
Original line number Diff line number Diff line
@@ -451,6 +451,11 @@ def LLVM_SelectOp 
    }]>];

  let assemblyFormat = "operands attr-dict `:` type($condition) `,` type($res)";

}

def LLVM_FreezeOp : LLVM_OneResultOp<"freeze", [SameOperandsAndResultType]>,

                    Arguments<(ins LLVM_Type:$val)> {

  let assemblyFormat = "$val attr-dict `:` type($val)";

  string llvmBuilder = "builder.CreateFreeze($val);";

}



// Terminators.

def LLVM_BrOp : LLVM_TerminatorOp<"br", []> {

mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp

+8 −1
Original line number Diff line number Diff line
@@ -426,6 +426,12 @@ Value Importer::processConstant(llvm::Constant *c) { 
    i->deleteValue();

    return instMap[c] = instMap[i];

  }

  if (auto *ue = dyn_cast<llvm::UndefValue>(c)) {

    LLVMType type = processType(ue->getType());

    if (!type)

      return nullptr;

    return instMap[c] = bEntry.create<UndefOp>(UnknownLoc::get(context), type);

  }

  emitError(unknownLoc) << "unhandled constant: " << diag(*c);

  return nullptr;

}
@@ -493,7 +499,7 @@ static const DenseMap<unsigned, StringRef> opcMap = { 
    // ICmp is handled specially.

    // FIXME: fcmp

    // PHI is handled specially.

    INST(Call, Call),

    INST(Freeze, Freeze), INST(Call, Call),

    // FIXME: select

    // FIXME: vaarg

    // FIXME: extractelement
@@ -591,6 +597,7 @@ LogicalResult Importer::processInstruction(llvm::Instruction *inst) { 
  case llvm::Instruction::PtrToInt:

  case llvm::Instruction::IntToPtr:

  case llvm::Instruction::AddrSpaceCast:

  case llvm::Instruction::Freeze:

  case llvm::Instruction::BitCast: {

    OperationState state(loc, opcMap.lookup(inst->getOpcode()));

    SmallVector<Value, 4> ops;

mlir/test/Dialect/LLVMIR/roundtrip.mlir

+11 −0
Original line number Diff line number Diff line
@@ -282,3 +282,14 @@ llvm.func @invokeLandingpad() -> !llvm.i32 { 
^bb4:

  llvm.return %0 : !llvm.i32

}



// CHECK-LABEL: @useFreezeOp

func @useFreezeOp(%arg0: !llvm.i32) {

  // CHECK:  = llvm.freeze %[[ARG0:.*]] : !llvm.i32

  %0 = llvm.freeze %arg0 : !llvm.i32

  // CHECK: %[[x:.*]] = llvm.mlir.undef : !llvm.i8

  %1 = llvm.mlir.undef : !llvm.i8

  // CHECK:  = llvm.freeze %[[x]] : !llvm.i8

  %2 = llvm.freeze %1 : !llvm.i8

  return

}
 
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mlir/test/Target/import.ll

+11 −0
Original line number Diff line number Diff line
@@ -297,3 +297,14 @@ define i32 @invokeLandingpad() personality i8* bitcast (i32 (...)* @__gxx_person 
  ; CHECK: llvm.return %{{[0-9]+}} : !llvm.i32

  ret i32 0

}



;CHECK-LABEL: @useFreezeOp

define i32 @useFreezeOp(i32 %x) {

  ;CHECK: %{{[0-9]+}} = llvm.freeze %{{[0-9a-z]+}} : !llvm.i32

  %1 = freeze i32 %x

  %2 = add i8 10, 10

  ;CHECK: %{{[0-9]+}} = llvm.freeze %{{[0-9]+}} : !llvm.i8

  %3 = freeze i8 %2

  %poison = add nsw i1 0, undef

  ret i32 0

}
 
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mlir/test/Target/llvmir.mlir

+10 −0
Original line number Diff line number Diff line
@@ -1171,3 +1171,13 @@ llvm.func @invokeLandingpad() -> !llvm.i32 { 
^bb3:	// pred: ^bb1

  %8 = llvm.invoke @bar(%6) to ^bb2 unwind ^bb1 : (!llvm<"i8*">) -> !llvm<"i8*">

}



// CHECK-LABEL: @callFreezeOp

llvm.func @callFreezeOp(%x : !llvm.i32) {

  // CHECK: freeze i32 %{{[0-9]+}}

  %0 = llvm.freeze %x : !llvm.i32

  %1 = llvm.mlir.undef : !llvm.i32

  // CHECK: freeze i32 undef 

  %2 = llvm.freeze %1 : !llvm.i32

  llvm.return

}
 
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