From b4cfd15d9901883cfb46ac3826e0a27573089372 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Fri, 17 Jul 2009 19:01:15 +0000 Subject: [PATCH] Define a no-pointer-overflow flag for GetElementPtr instructions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76218 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Instructions.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/include/llvm/Instructions.h b/include/llvm/Instructions.h index 9a20a2fd0c2..f2253e1ccc6 100644 --- a/include/llvm/Instructions.h +++ b/include/llvm/Instructions.h @@ -573,6 +573,23 @@ public: /// a constant offset between them. bool hasAllConstantIndices() const; + /// hasNoPointerOverflow - Return true if this GetElementPtr is known to + /// never have overflow in the pointer addition portions of its effective + /// computation. GetElementPtr computation involves several phases; + /// overflow can be considered to occur in index typecasting, array index + /// scaling, and the addition of the base pointer with offsets. This flag + /// only applies to the last of these. The operands are added to the base + /// pointer one at a time from left to right. This function returns false + /// if any of these additions results in an address value which is not + /// known to be within the allocated address space that the base pointer + /// points into, or within one element (of the original allocation) past + /// the end. + bool hasNoPointerOverflow() const { + return SubclassOptionalData & (1 << 0); + } + void setHasNoPointerOverflow(bool B) { + SubclassOptionalData = (SubclassOptionalData & ~(1 << 0)) | (B << 0); + } // Methods for support type inquiry through isa, cast, and dyn_cast: static inline bool classof(const GetElementPtrInst *) { return true; }