diff options
Diffstat (limited to 'include/llvm/Analysis/ConstantFolding.h')
| -rw-r--r-- | include/llvm/Analysis/ConstantFolding.h | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/include/llvm/Analysis/ConstantFolding.h b/include/llvm/Analysis/ConstantFolding.h index e2675eb..f6b1f5a 100644 --- a/include/llvm/Analysis/ConstantFolding.h +++ b/include/llvm/Analysis/ConstantFolding.h @@ -7,7 +7,8 @@ // //===----------------------------------------------------------------------===// // -// 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 @@ -27,11 +28,11 @@ namespace llvm { 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 |
