//
//===----------------------------------------------------------------------===//
//
-// This file declares routines for folding instructions into constants.
+// This file declares routines for folding instructions into constants when all
+// operands are constants, for example "sub i32 1, 0" -> "1".
//
// Also, to supplement the basic VMCore ConstantExpr simplifications,
// this file declares some additional folding routines that can make use of
class Function;
class Type;
-/// ConstantFoldInstruction - Attempt to constant fold the specified
-/// instruction. If successful, the constant result is returned, if not, null
-/// is returned. Note that this function can only fail when attempting to fold
-/// instructions like loads and stores, which have no constant expression form.
-///
+/// ConstantFoldInstruction - Try to constant fold the specified instruction.
+/// If successful, the constant result is returned, if not, null is returned.
+/// Note that this fails if not all of the operands are constant. Otherwise,
+/// this function can only fail when attempting to fold instructions like loads
+/// and stores, which have no constant expression form.
Constant *ConstantFoldInstruction(Instruction *I, const TargetData *TD = 0);
/// ConstantFoldConstantExpression - Attempt to fold the constant expression