Add a new function to ConstantExpr - getAsInstruction. This returns its Instruction* corollary, which may be useful if a user

wishes to transform a ConstantExpr so that one of its operands is no longer constant.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168262 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 179 insertions, 0 deletions

diff --git a/include/llvm/Constants.h b/include/llvm/Constants.h
index b7d1a488f5..3308499192 100644
--- a/include/llvm/Constants.h
+++ b/include/llvm/Constants.h
@@ -1076,6 +1076,16 @@ public:
   /// current one.
   Constant *getWithOperands(ArrayRef<Constant*> Ops, Type *Ty) const;
 
+  /// getAsInstruction - Returns an Instruction which implements the same operation
+  /// as this ConstantExpr. The instruction is not linked to any basic block.
+  ///
+  /// A better approach to this could be to have a constructor for Instruction
+  /// which would take a ConstantExpr parameter, but that would have spread 
+  /// implementation details of ConstantExpr outside of Constants.cpp, which 
+  /// would make it harded to remove ConstantExprs altogether
+  /// (http://llvm.org/bugs/show_bug.cgi?id=10368).
+  Instruction *getAsInstruction();
+
   virtual void destroyConstant();
   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U);
 
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 935f6b2bc1..a4514309b2 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -2704,3 +2704,66 @@ void ConstantExpr::replaceUsesOfWithOnConstant(Value *From, Value *ToV,
   // Delete the old constant!
   destroyConstant();
 }
+
+Instruction *ConstantExpr::getAsInstruction() {
+  SmallVector<Value*,4> ValueOperands;
+  for (op_iterator I = op_begin(), E = op_end(); I != E; ++I)
+    ValueOperands.push_back(cast<Value>(I));
+
+  ArrayRef<Value*> Ops(ValueOperands);
+
+  switch (getOpcode()) {
+  case Instruction::Trunc:
+  case Instruction::ZExt:
+  case Instruction::SExt:
+  case Instruction::FPTrunc:
+  case Instruction::FPExt:
+  case Instruction::UIToFP:
+  case Instruction::SIToFP:
+  case Instruction::FPToUI:
+  case Instruction::FPToSI:
+  case Instruction::PtrToInt:
+  case Instruction::IntToPtr:
+  case Instruction::BitCast:
+    return CastInst::Create((Instruction::CastOps)getOpcode(),
+                            Ops[0], getType());
+  case Instruction::Select:
+    return SelectInst::Create(Ops[0], Ops[1], Ops[2]);
+  case Instruction::InsertElement:
+    return InsertElementInst::Create(Ops[0], Ops[1], Ops[2]);
+  case Instruction::ExtractElement:
+    return ExtractElementInst::Create(Ops[0], Ops[1]);
+  case Instruction::InsertValue:
+    return InsertValueInst::Create(Ops[0], Ops[1], getIndices());
+  case Instruction::ExtractValue:
+    return ExtractValueInst::Create(Ops[0], getIndices());
+  case Instruction::ShuffleVector:
+    return new ShuffleVectorInst(Ops[0], Ops[1], Ops[2]);
+
+  case Instruction::GetElementPtr:
+    if (cast<GEPOperator>(this)->isInBounds())
+      return GetElementPtrInst::CreateInBounds(Ops[0], Ops.slice(1));
+    else
+      return GetElementPtrInst::Create(Ops[0], Ops.slice(1));
+
+  case Instruction::ICmp:
+  case Instruction::FCmp:
+    return CmpInst::Create((Instruction::OtherOps)getOpcode(),
+                           getPredicate(), Ops[0], Ops[1]);
+
+  default:
+    assert(getNumOperands() == 2 && "Must be binary operator?");
+    BinaryOperator *BO =
+      BinaryOperator::Create((Instruction::BinaryOps)getOpcode(),
+                             Ops[0], Ops[1]);
+    if (isa<OverflowingBinaryOperator>(BO)) {
+      BO->setHasNoUnsignedWrap(SubclassOptionalData &
+                               OverflowingBinaryOperator::NoUnsignedWrap);
+      BO->setHasNoSignedWrap(SubclassOptionalData &
+                             OverflowingBinaryOperator::NoSignedWrap);
+    }
+    if (isa<PossiblyExactOperator>(BO))
+      BO->setIsExact(SubclassOptionalData & PossiblyExactOperator::IsExact);
+    return BO;
+  }
+}
diff --git a/unittests/VMCore/ConstantsTest.cpp b/unittests/VMCore/ConstantsTest.cpp
index 623ea0d102..25d61cc6ca 100644
--- a/unittests/VMCore/ConstantsTest.cpp
+++ b/unittests/VMCore/ConstantsTest.cpp
@@ -8,8 +8,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Constants.h"
+#include "llvm/Instruction.h"
+#include "llvm/InstrTypes.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/LLVMContext.h"
+#include "llvm/Module.h"
 #include "gtest/gtest.h"
 
 namespace llvm {
@@ -118,5 +121,108 @@ TEST(ConstantsTest, FP128Test) {
   EXPECT_TRUE(isa<ConstantFP>(X));
 }
 
+#define CHECK(x, y) {                                           \
+    std::string __s;                                            \
+    raw_string_ostream __o(__s);                                \
+    cast<ConstantExpr>(x)->getAsInstruction()->print(__o);      \
+    __o.flush();                                                \
+    EXPECT_EQ(std::string("  <badref> = " y), __s);             \
+  }
+
+TEST(ConstantsTest, AsInstructionsTest) {
+  Module *M = new Module("MyModule", getGlobalContext());
+
+  Type *Int64Ty = Type::getInt64Ty(getGlobalContext());
+  Type *Int32Ty = Type::getInt32Ty(getGlobalContext());
+  Type *Int16Ty = Type::getInt16Ty(getGlobalContext());
+  Type *Int1Ty = Type::getInt1Ty(getGlobalContext());
+  Type *FloatTy = Type::getFloatTy(getGlobalContext());
+  Type *DoubleTy = Type::getDoubleTy(getGlobalContext());
+
+  Constant *Global = M->getOrInsertGlobal("dummy",
+                                         PointerType::getUnqual(Int32Ty));
+  Constant *Global2 = M->getOrInsertGlobal("dummy2",
+                                         PointerType::getUnqual(Int32Ty));
+
+  Constant *P0 = ConstantExpr::getPtrToInt(Global, Int32Ty);
+  Constant *P1 = ConstantExpr::getUIToFP(P0, FloatTy);
+  Constant *P2 = ConstantExpr::getUIToFP(P0, DoubleTy);
+  Constant *P3 = ConstantExpr::getTrunc(P0, Int1Ty);
+  Constant *P4 = ConstantExpr::getPtrToInt(Global2, Int32Ty);
+  Constant *P5 = ConstantExpr::getUIToFP(P4, FloatTy);
+  Constant *P6 = ConstantExpr::getBitCast(P4, VectorType::get(Int16Ty, 2));
+
+  Constant *One = ConstantInt::get(Int32Ty, 1);
+
+  #define P0STR "ptrtoint (i32** @dummy to i32)"
+  #define P1STR "uitofp (i32 ptrtoint (i32** @dummy to i32) to float)"
+  #define P2STR "uitofp (i32 ptrtoint (i32** @dummy to i32) to double)"
+  #define P3STR "ptrtoint (i32** @dummy to i1)"
+  #define P4STR "ptrtoint (i32** @dummy2 to i32)"
+  #define P5STR "uitofp (i32 ptrtoint (i32** @dummy2 to i32) to float)"
+  #define P6STR "bitcast (i32 ptrtoint (i32** @dummy2 to i32) to <2 x i16>)"
+
+  CHECK(ConstantExpr::getNeg(P0), "sub i32 0, " P0STR);
+  CHECK(ConstantExpr::getFNeg(P1), "fsub float -0.000000e+00, " P1STR);
+  CHECK(ConstantExpr::getNot(P0), "xor i32 " P0STR ", -1");
+  CHECK(ConstantExpr::getAdd(P0, P0), "add i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getAdd(P0, P0, false, true), "add nsw i32 " P0STR ", "
+        P0STR);
+  CHECK(ConstantExpr::getAdd(P0, P0, true, true), "add nuw nsw i32 " P0STR ", "
+        P0STR);
+  CHECK(ConstantExpr::getFAdd(P1, P1), "fadd float " P1STR ", " P1STR);
+  CHECK(ConstantExpr::getSub(P0, P0), "sub i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getFSub(P1, P1), "fsub float " P1STR ", " P1STR);
+  CHECK(ConstantExpr::getMul(P0, P0), "mul i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getFMul(P1, P1), "fmul float " P1STR ", " P1STR);
+  CHECK(ConstantExpr::getUDiv(P0, P0), "udiv i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getSDiv(P0, P0), "sdiv i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getFDiv(P1, P1), "fdiv float " P1STR ", " P1STR);
+  CHECK(ConstantExpr::getURem(P0, P0), "urem i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getSRem(P0, P0), "srem i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getFRem(P1, P1), "frem float " P1STR ", " P1STR);
+  CHECK(ConstantExpr::getAnd(P0, P0), "and i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getOr(P0, P0), "or i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getXor(P0, P0), "xor i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getShl(P0, P0), "shl i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getShl(P0, P0, true), "shl nuw i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getShl(P0, P0, false, true), "shl nsw i32 " P0STR ", "
+        P0STR);
+  CHECK(ConstantExpr::getLShr(P0, P0, false), "lshr i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getLShr(P0, P0, true), "lshr exact i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getAShr(P0, P0, false), "ashr i32 " P0STR ", " P0STR);
+  CHECK(ConstantExpr::getAShr(P0, P0, true), "ashr exact i32 " P0STR ", " P0STR);
+
+  CHECK(ConstantExpr::getSExt(P0, Int64Ty), "sext i32 " P0STR " to i64");
+  CHECK(ConstantExpr::getZExt(P0, Int64Ty), "zext i32 " P0STR " to i64");
+  CHECK(ConstantExpr::getFPTrunc(P2, FloatTy), "fptrunc double " P2STR
+        " to float");
+  CHECK(ConstantExpr::getFPExtend(P1, DoubleTy), "fpext float " P1STR
+        " to double");
+
+  CHECK(ConstantExpr::getExactUDiv(P0, P0), "udiv exact i32 " P0STR ", " P0STR);
+
+  CHECK(ConstantExpr::getSelect(P3, P0, P4), "select i1 " P3STR ", i32 " P0STR
+        ", i32 " P4STR);
+  CHECK(ConstantExpr::getICmp(CmpInst::ICMP_EQ, P0, P4), "icmp eq i32 " P0STR
+        ", " P4STR);
+  CHECK(ConstantExpr::getFCmp(CmpInst::FCMP_ULT, P1, P5), "fcmp ult float "
+        P1STR ", " P5STR);
+
+  std::vector<Constant*> V;
+  V.push_back(One);
+  // FIXME: getGetElementPtr() actually creates an inbounds ConstantGEP,
+  //        not a normal one!
+  //CHECK(ConstantExpr::getGetElementPtr(Global, V, false),
+  //      "getelementptr i32** @dummy, i32 1");
+  CHECK(ConstantExpr::getInBoundsGetElementPtr(Global, V),
+        "getelementptr inbounds i32** @dummy, i32 1");
+
+  CHECK(ConstantExpr::getExtractElement(P6, One), "extractelement <2 x i16> "
+        P6STR ", i32 1");
+}
+
+#undef CHECK
+
 }  // end anonymous namespace
 }  // end namespace llvm