1 //===-- HexagonTargetTransformInfo.cpp - Hexagon specific TTI pass --------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
9 /// This file implements a TargetTransformInfo analysis pass specific to the
10 /// Hexagon target machine. It uses the target's detailed information to provide
11 /// more precise answers to certain TTI queries, while letting the target
12 /// independent and default TTI implementations handle the rest.
14 //===----------------------------------------------------------------------===//
16 #include "HexagonTargetTransformInfo.h"
17 #include "llvm/IR/Instructions.h"
18 #include "llvm/Support/Debug.h"
22 #define DEBUG_TYPE "hexagontti"
24 TargetTransformInfo::PopcntSupportKind
25 HexagonTTIImpl::getPopcntSupport(unsigned IntTyWidthInBit) const {
26 // Return Fast Hardware support as every input < 64 bits will be promoted
28 return TargetTransformInfo::PSK_FastHardware;
31 // The Hexagon target can unroll loops with run-time trip counts.
32 void HexagonTTIImpl::getUnrollingPreferences(Loop *L,
33 TTI::UnrollingPreferences &UP) {
34 UP.Runtime = UP.Partial = true;
37 unsigned HexagonTTIImpl::getNumberOfRegisters(bool vector) const {
38 return vector ? 0 : 32;
41 unsigned HexagonTTIImpl::getPrefetchDistance() const {
42 return getST()->getL1PrefetchDistance();
45 unsigned HexagonTTIImpl::getCacheLineSize() const {
46 return getST()->getL1CacheLineSize();
49 int HexagonTTIImpl::getUserCost(const User *U) {
50 auto isCastFoldedIntoLoad = [] (const CastInst *CI) -> bool {
51 if (!CI->isIntegerCast())
53 const LoadInst *LI = dyn_cast<const LoadInst>(CI->getOperand(0));
54 // Technically, this code could allow multiple uses of the load, and
55 // check if all the uses are the same extension operation, but this
56 // should be sufficient for most cases.
57 if (!LI || !LI->hasOneUse())
60 // Only extensions from an integer type shorter than 32-bit to i32
61 // can be folded into the load.
62 unsigned SBW = CI->getSrcTy()->getIntegerBitWidth();
63 unsigned DBW = CI->getDestTy()->getIntegerBitWidth();
64 return DBW == 32 && (SBW < DBW);
67 if (const CastInst *CI = dyn_cast<const CastInst>(U))
68 if (isCastFoldedIntoLoad(CI))
69 return TargetTransformInfo::TCC_Free;
70 return BaseT::getUserCost(U);