[llvm] d196f9e - [InstructionCost] Prevent InstructionCost being created with CostState.

[Sander de Smalen via llvm-commits]

Author: Sander de Smalen
Date: 2021-01-25T11:26:56Z
New Revision: d196f9e2fca3ff767aa7d2dcaf4654724a79e18c

URL: https://github.com/llvm/llvm-project/commit/d196f9e2fca3ff767aa7d2dcaf4654724a79e18c
DIFF: https://github.com/llvm/llvm-project/commit/d196f9e2fca3ff767aa7d2dcaf4654724a79e18c.diff

LOG: [InstructionCost] Prevent InstructionCost being created with CostState.

For a function that returns InstructionCost, it is very tempting to write:

  return InstructionCost::Invalid;

But that actually returns InstructionCost(1 /* int value of Invalid */))
which has a totally different meaning. By marking this constructor as
`delete`, this can no longer happen.

Added: 
    

Modified: 
    llvm/include/llvm/Support/InstructionCost.h

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Support/InstructionCost.h b/llvm/include/llvm/Support/InstructionCost.h
index 725f8495ac09..fbc898b878bb 100644
--- a/llvm/include/llvm/Support/InstructionCost.h
+++ b/llvm/include/llvm/Support/InstructionCost.h
@@ -47,6 +47,7 @@ class InstructionCost {
 public:
   InstructionCost() = default;
 
+  InstructionCost(CostState) = delete;
   InstructionCost(CostType Val) : Value(Val), State(Valid) {}
 
   static InstructionCost getInvalid(CostType Val = 0) {