From ea8888d1af3a992d82d1ff3bf99537220828d388 Mon Sep 17 00:00:00 2001 From: Alex Richardson Date: Fri, 13 Dec 2019 19:43:02 +0000 Subject: [PATCH] [NFC] Add a SDValue overload for SelectionDAG::getMemBasePlusOffset() Summary: This change is preparatory work to use this helper functions in more places. Currently the function only allows integer constants offsets, but there are cases where we can use an existing SDValue parameter. The motivation for this change is our out-of-tree CHERI backend (https://github.com/CTSRD-CHERI/llvm-project). We use a separate register type to store pointers (128-bit capabilities, which are effectively unforgeable and monotonic fat pointers). These capabilities permit a reduced set of operations and therefore use a separate ValueType (iFATPTR). to represent pointers implemented as capabilities. Therefore, we need to avoid using ISD::ADD for our patterns that operate on pointers and need to use a function that chooses ISD::ADD or a new ISD::PTRADD opcode depending on the value type. We originally added a new DAG.getPointerAdd() function, but after this patch series we can modify the implementation of getMemBasePlusOffset() instead. Avoiding direct uses of ISD::ADD for pointer types will significantly reduce the amount of assertion/instruction selection failures for us in future upstream merges. Reviewers: spatel, craig.topper Reviewed By: spatel, craig.topper Subscribers: craig.topper, merge_guards_bot, hiraditya, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D71205 --- llvm/include/llvm/CodeGen/SelectionDAG.h | 1 + llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 9 ++++++++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/llvm/include/llvm/CodeGen/SelectionDAG.h b/llvm/include/llvm/CodeGen/SelectionDAG.h index ffc4f8e..7f331d1 100644 --- a/llvm/include/llvm/CodeGen/SelectionDAG.h +++ b/llvm/include/llvm/CodeGen/SelectionDAG.h @@ -1140,6 +1140,7 @@ public: /// Returns sum of the base pointer and offset. /// Unlike getObjectPtrOffset this does not set NoUnsignedWrap by default. SDValue getMemBasePlusOffset(SDValue Base, int64_t Offset, const SDLoc &DL); + SDValue getMemBasePlusOffset(SDValue Base, SDValue Offset, const SDLoc &DL); SDValue getMaskedLoad(EVT VT, const SDLoc &dl, SDValue Chain, SDValue Base, SDValue Offset, SDValue Mask, SDValue Src0, EVT MemVT, diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 378e336..3379d5b 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -5735,7 +5735,14 @@ static SDValue getMemsetStringVal(EVT VT, const SDLoc &dl, SelectionDAG &DAG, SDValue SelectionDAG::getMemBasePlusOffset(SDValue Base, int64_t Offset, const SDLoc &DL) { EVT VT = Base.getValueType(); - return getNode(ISD::ADD, DL, VT, Base, getConstant(Offset, DL, VT)); + return getMemBasePlusOffset(Base, getConstant(Offset, DL, VT), DL); +} + +SDValue SelectionDAG::getMemBasePlusOffset(SDValue Ptr, SDValue Offset, + const SDLoc &DL) { + assert(Offset.getValueType().isInteger()); + EVT BasePtrVT = Ptr.getValueType(); + return getNode(ISD::ADD, DL, BasePtrVT, Ptr, Offset); } /// Returns true if memcpy source is constant data. -- 2.7.4