Change ConstantFoldInstOperands to take Instruction instead of opcode…

… and type. NFC.

Summary:
The previous form, taking opcode and type, is moved to an internal
helper and the new form, taking an instruction, is a wrapper around this
helper.

Although this is a slight cleanup on its own, the main motivation is to
refactor the constant folding API to ease migration to opaque pointers.
This will be follow-up work.

Reviewers: eddyb

Subscribers: dblaikie, llvm-commits

Differential Revision: http://reviews.llvm.org/D16383

llvm-svn: 258391

llvm/include/llvm/Analysis/ConstantFolding.h

@@ -51,8 +51,7 @@ ConstantFoldConstantExpression(const ConstantExpr *CE, const DataLayout &DL,
 /// fold instructions like loads and stores, which have no constant expression
 /// form.
 ///
-Constant *ConstantFoldInstOperands(unsigned Opcode, Type *DestTy,
-                                   ArrayRef<Constant *> Ops,
+Constant *ConstantFoldInstOperands(Instruction *I, ArrayRef<Constant *> Ops,
                                    const DataLayout &DL,
                                    const TargetLibraryInfo *TLI = nullptr);
 

llvm/lib/Analysis/ConstantFolding.cpp

@@ -881,6 +881,56 @@ static Constant *SymbolicallyEvaluateGEP(Type *SrcTy, ArrayRef<Constant *> Ops,
   return C;
 }
 
+/// Attempt to constant fold an instruction with the
+/// specified opcode and operands.  If successful, the constant result is
+/// returned, if not, null is returned.  Note that this function can fail when
+/// attempting to fold instructions like loads and stores, which have no
+/// constant expression form.
+///
+/// TODO: This function neither utilizes nor preserves nsw/nuw/inbounds/etc
+/// information, due to only being passed an opcode and operands. Constant
+/// folding using this function strips this information.
+///
+static Constant *ConstantFoldInstOperandsImpl(unsigned Opcode, Type *DestTy,
+                                              ArrayRef<Constant *> Ops,
+                                              const DataLayout &DL,
+                                              const TargetLibraryInfo *TLI) {
+  // Handle easy binops first.
+  if (Instruction::isBinaryOp(Opcode))
+    return ConstantFoldBinaryOpOperands(Opcode, Ops[0], Ops[1], DL);
+
+  if (Instruction::isCast(Opcode))
+    return ConstantFoldCastOperand(Opcode, Ops[0], DestTy, DL);
+
+  switch (Opcode) {
+  default: return nullptr;
+  case Instruction::ICmp:
+  case Instruction::FCmp: llvm_unreachable("Invalid for compares");
+  case Instruction::Call:
+    if (Function *F = dyn_cast<Function>(Ops.back()))
+      if (canConstantFoldCallTo(F))
+        return ConstantFoldCall(F, Ops.slice(0, Ops.size() - 1), TLI);
+    return nullptr;
+  case Instruction::Select:
+    return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]);
+  case Instruction::ExtractElement:
+    return ConstantExpr::getExtractElement(Ops[0], Ops[1]);
+  case Instruction::InsertElement:
+    return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2]);
+  case Instruction::ShuffleVector:
+    return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2]);
+  case Instruction::GetElementPtr: {
+    Type *SrcTy = nullptr;
+    if (Constant *C = CastGEPIndices(SrcTy, Ops, DestTy, DL, TLI))
+      return C;
+    if (Constant *C = SymbolicallyEvaluateGEP(SrcTy, Ops, DestTy, DL, TLI))
+      return C;
+
+    return ConstantExpr::getGetElementPtr(SrcTy, Ops[0], Ops.slice(1));
+  }
+  }
+}
+
 
 
 //===----------------------------------------------------------------------===//
@@ -925,7 +975,7 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const DataLayout &DL,
   }
 
   // Scan the operand list, checking to see if they are all constants, if so,
-  // hand off to ConstantFoldInstOperands.
+  // hand off to ConstantFoldInstOperandsImpl.
   SmallVector<Constant*, 8> Ops;
   for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) {
     Constant *Op = dyn_cast<Constant>(*i);
@@ -959,7 +1009,7 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const DataLayout &DL,
                                     EVI->getIndices());
   }
 
-  return ConstantFoldInstOperands(I->getOpcode(), I->getType(), Ops, DL, TLI);
+  return ConstantFoldInstOperandsImpl(I->getOpcode(), I->getType(), Ops, DL, TLI);
 }
 
 static Constant *
@@ -982,7 +1032,7 @@ ConstantFoldConstantExpressionImpl(const ConstantExpr *CE, const DataLayout &DL,
   if (CE->isCompare())
     return ConstantFoldCompareInstOperands(CE->getPredicate(), Ops[0], Ops[1],
                                            DL, TLI);
-  return ConstantFoldInstOperands(CE->getOpcode(), CE->getType(), Ops, DL, TLI);
+  return ConstantFoldInstOperandsImpl(CE->getOpcode(), CE->getType(), Ops, DL, TLI);
 }
 
 /// Attempt to fold the constant expression
@@ -995,54 +1045,12 @@ Constant *llvm::ConstantFoldConstantExpression(const ConstantExpr *CE,
   return ConstantFoldConstantExpressionImpl(CE, DL, TLI, FoldedOps);
 }
 
-/// Attempt to constant fold an instruction with the
-/// specified opcode and operands.  If successful, the constant result is
-/// returned, if not, null is returned.  Note that this function can fail when
-/// attempting to fold instructions like loads and stores, which have no
-/// constant expression form.
-///
-/// TODO: This function neither utilizes nor preserves nsw/nuw/inbounds/etc
-/// information, due to only being passed an opcode and operands. Constant
-/// folding using this function strips this information.
-///
-Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, Type *DestTy,
+Constant *llvm::ConstantFoldInstOperands(Instruction *I,
                                          ArrayRef<Constant *> Ops,
                                          const DataLayout &DL,
                                          const TargetLibraryInfo *TLI) {
-  // Handle easy binops first.
-  if (Instruction::isBinaryOp(Opcode))
-    return ConstantFoldBinaryOpOperands(Opcode, Ops[0], Ops[1], DL);
-
-  if (Instruction::isCast(Opcode))
-    return ConstantFoldCastOperand(Opcode, Ops[0], DestTy, DL);
-
-  switch (Opcode) {
-  default: return nullptr;
-  case Instruction::ICmp:
-  case Instruction::FCmp: llvm_unreachable("Invalid for compares");
-  case Instruction::Call:
-    if (Function *F = dyn_cast<Function>(Ops.back()))
-      if (canConstantFoldCallTo(F))
-        return ConstantFoldCall(F, Ops.slice(0, Ops.size() - 1), TLI);
-    return nullptr;
-  case Instruction::Select:
-    return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]);
-  case Instruction::ExtractElement:
-    return ConstantExpr::getExtractElement(Ops[0], Ops[1]);
-  case Instruction::InsertElement:
-    return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2]);
-  case Instruction::ShuffleVector:
-    return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2]);
-  case Instruction::GetElementPtr: {
-    Type *SrcTy = nullptr;
-    if (Constant *C = CastGEPIndices(SrcTy, Ops, DestTy, DL, TLI))
-      return C;
-    if (Constant *C = SymbolicallyEvaluateGEP(SrcTy, Ops, DestTy, DL, TLI))
-      return C;
-
-    return ConstantExpr::getGetElementPtr(SrcTy, Ops[0], Ops.slice(1));
-  }
-  }
+  return ConstantFoldInstOperandsImpl(I->getOpcode(), I->getType(), Ops, DL,
+                                      TLI);
 }
 
 /// Attempt to constant fold a compare

llvm/lib/Analysis/InlineCost.cpp

@@ -533,8 +533,7 @@ bool CallAnalyzer::visitUnaryInstruction(UnaryInstruction &I) {
     COp = SimplifiedValues.lookup(Operand);
   if (COp) {
     const DataLayout &DL = F.getParent()->getDataLayout();
-    if (Constant *C = ConstantFoldInstOperands(I.getOpcode(), I.getType(),
-                                               COp, DL)) {
+    if (Constant *C = ConstantFoldInstOperands(&I, COp, DL)) {
       SimplifiedValues[&I] = C;
       return true;
     }

llvm/lib/Analysis/InstructionSimplify.cpp

@@ -3261,8 +3261,7 @@ static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
         if (!LI->isVolatile())
           return ConstantFoldLoadFromConstPtr(ConstOps[0], Q.DL);
 
-      return ConstantFoldInstOperands(I->getOpcode(), I->getType(), ConstOps,
-                                      Q.DL, Q.TLI);
+      return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
     }
   }
 

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -5917,8 +5917,7 @@ static Constant *EvaluateExpression(Value *V, const Loop *L,
     if (!LI->isVolatile())
       return ConstantFoldLoadFromConstPtr(Operands[0], DL);
   }
-  return ConstantFoldInstOperands(I->getOpcode(), I->getType(), Operands, DL,
-                                  TLI);
+  return ConstantFoldInstOperands(I, Operands, DL, TLI);
 }
 
 
@@ -6306,8 +6305,7 @@ const SCEV *ScalarEvolution::computeSCEVAtScope(const SCEV *V, const Loop *L) {
             if (!LI->isVolatile())
               C = ConstantFoldLoadFromConstPtr(Operands[0], DL);
           } else
-            C = ConstantFoldInstOperands(I->getOpcode(), I->getType(), Operands,
-                                         DL, &TLI);
+            C = ConstantFoldInstOperands(I, Operands, DL, &TLI);
           if (!C) return V;
           return getSCEV(C);
         }

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -3989,7 +3989,7 @@ ConstantFold(Instruction *I, const DataLayout &DL,
                                            COps[1], DL);
   }
 
-  return ConstantFoldInstOperands(I->getOpcode(), I->getType(), COps, DL);
+  return ConstantFoldInstOperands(I, COps, DL);
 }
 
 /// Try to determine the resulting constant values in phi nodes