[llvm] ef8b4e4 - Add validity assert on entry to CastInst::isNoopCast [NFC]

[Philip Reames via llvm-commits]

Author: Philip Reames
Date: 2020-10-07T14:05:45-07:00
New Revision: ef8b4e4fcd687f66ef0271d1257075f1f53dd34b

URL: https://github.com/llvm/llvm-project/commit/ef8b4e4fcd687f66ef0271d1257075f1f53dd34b
DIFF: https://github.com/llvm/llvm-project/commit/ef8b4e4fcd687f66ef0271d1257075f1f53dd34b.diff

LOG: Add validity assert on entry to CastInst::isNoopCast [NFC]

This required some minor code reorganization to have a version of castIsValid which worked purely in terms of types.

Added: 
    

Modified: 
    llvm/include/llvm/IR/InstrTypes.h
    llvm/lib/IR/Instructions.cpp

Removed: 
    


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diff  --git a/llvm/include/llvm/IR/InstrTypes.h b/llvm/include/llvm/IR/InstrTypes.h
index c86448ea72cb..810e87de232b 100644
--- a/llvm/include/llvm/IR/InstrTypes.h
+++ b/llvm/include/llvm/IR/InstrTypes.h
@@ -691,11 +691,14 @@ class CastInst : public UnaryInstruction {
   /// Return the destination type, as a convenience
   Type* getDestTy() const { return getType(); }
 
-  /// This method can be used to determine if a cast from S to DstTy using
+  /// This method can be used to determine if a cast from SrcTy to DstTy using
   /// Opcode op is valid or not.
   /// @returns true iff the proposed cast is valid.
   /// Determine if a cast is valid without creating one.
-  static bool castIsValid(Instruction::CastOps op, Value *S, Type *DstTy);
+  static bool castIsValid(Instruction::CastOps op, Type *SrcTy, Type *DstTy);
+  static bool castIsValid(Instruction::CastOps op, Value *S, Type *DstTy) {
+    return castIsValid(op, S->getType(), DstTy);
+  }
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Instruction *I) {

diff  --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index 445fad8bcbf4..b8663cdcbe83 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -2654,6 +2654,7 @@ bool CastInst::isNoopCast(Instruction::CastOps Opcode,
                           Type *SrcTy,
                           Type *DestTy,
                           const DataLayout &DL) {
+  assert(castIsValid(Opcode, SrcTy, DestTy) && "method precondition");
   switch (Opcode) {
     default: llvm_unreachable("Invalid CastOp");
     case Instruction::Trunc:
@@ -3352,10 +3353,7 @@ CastInst::getCastOpcode(
 /// it in one place and to eliminate the redundant code for getting the sizes
 /// of the types involved.
 bool
-CastInst::castIsValid(Instruction::CastOps op, Value *S, Type *DstTy) {
-  // Check for type sanity on the arguments
-  Type *SrcTy = S->getType();
-
+CastInst::castIsValid(Instruction::CastOps op, Type *SrcTy, Type *DstTy) {
   if (!SrcTy->isFirstClassType() || !DstTy->isFirstClassType() ||
       SrcTy->isAggregateType() || DstTy->isAggregateType())
     return false;