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966bb89b1a
Making a width of GEP Index, which is used for address calculation, to be one of the pointer properties in the Data Layout. p[address space]:size:memory_size:alignment:pref_alignment:index_size_in_bits. The index size parameter is optional, if not specified, it is equal to the pointer size. Till now, the InstCombiner normalized GEPs and extended the Index operand to the pointer width. It works fine if you can convert pointer to integer for address calculation and all registered targets do this. But some ISAs have very restricted instruction set for the pointer calculation. During discussions were desided to retrieve information for GEP index from the Data Layout. http://lists.llvm.org/pipermail/llvm-dev/2018-January/120416.html I added an interface to the Data Layout and I changed the InstCombiner and some other passes to take the Index width into account. This change does not affect any in-tree target. I added tests to cover data layouts with explicitly specified index size. Differential Revision: https://reviews.llvm.org/D42123 llvm-svn: 325102
65 lines
2.3 KiB
C++
65 lines
2.3 KiB
C++
//===-- Operator.cpp - Implement the LLVM operators -----------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the non-inline methods for the LLVM Operator classes.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/IR/Operator.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/GetElementPtrTypeIterator.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/Type.h"
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#include "ConstantsContext.h"
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namespace llvm {
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Type *GEPOperator::getSourceElementType() const {
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if (auto *I = dyn_cast<GetElementPtrInst>(this))
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return I->getSourceElementType();
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return cast<GetElementPtrConstantExpr>(this)->getSourceElementType();
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}
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Type *GEPOperator::getResultElementType() const {
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if (auto *I = dyn_cast<GetElementPtrInst>(this))
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return I->getResultElementType();
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return cast<GetElementPtrConstantExpr>(this)->getResultElementType();
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}
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bool GEPOperator::accumulateConstantOffset(const DataLayout &DL,
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APInt &Offset) const {
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assert(Offset.getBitWidth() ==
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DL.getIndexSizeInBits(getPointerAddressSpace()) &&
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"The offset bit width does not match DL specification.");
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for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
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GTI != GTE; ++GTI) {
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ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
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if (!OpC)
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return false;
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if (OpC->isZero())
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continue;
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// Handle a struct index, which adds its field offset to the pointer.
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if (StructType *STy = GTI.getStructTypeOrNull()) {
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unsigned ElementIdx = OpC->getZExtValue();
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const StructLayout *SL = DL.getStructLayout(STy);
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Offset += APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx));
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continue;
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}
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// For array or vector indices, scale the index by the size of the type.
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APInt Index = OpC->getValue().sextOrTrunc(Offset.getBitWidth());
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Offset += Index * APInt(Offset.getBitWidth(),
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DL.getTypeAllocSize(GTI.getIndexedType()));
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}
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return true;
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}
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}
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