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llvm-mirror/lib/Target/Sparc/SparcRegClassInfo.cpp
Vikram S. Adve 48144de834 (1) Major fix to the way unused regs. are marked and found for the FP
Single and FP double reg types (which share the same reg class).
    Now all methods marking/finding unused regs consider the regType
    within the reg class, and SparcFloatRegClass specializes this code.
(2) Remove machine-specific regalloc. methods that are no longer needed.
    In particular, arguments and return value from a call do not need
    machine-specific code for allocation.
(3) Rename TargetRegInfo::getRegType variants to avoid unintentional
    overloading when an include file is omitted.

llvm-svn: 7334
2003-07-25 21:12:15 +00:00

372 lines
14 KiB
C++

//===-- SparcRegClassInfo.cpp - Register class def'ns for Sparc -----------===//
//
// This file defines the register classes used by the Sparc target description.
//
//===----------------------------------------------------------------------===//
#include "SparcRegClassInfo.h"
#include "SparcInternals.h"
#include "llvm/Type.h"
#include "../../CodeGen/RegAlloc/RegAllocCommon.h" // FIXME!
//-----------------------------------------------------------------------------
// Int Register Class - method for coloring a node in the interference graph.
//
// Algorithm:
// Record the colors/suggested colors of all neighbors.
//
// If there is a suggested color, try to allocate it
// If there is no call interf, try to allocate volatile, then non volatile
// If there is call interf, try to allocate non-volatile. If that fails
// try to allocate a volatile and insert save across calls
// If both above fail, spill.
//
//-----------------------------------------------------------------------------
void SparcIntRegClass::colorIGNode(IGNode * Node,
const std::vector<bool> &IsColorUsedArr) const
{
LiveRange *LR = Node->getParentLR();
if (DEBUG_RA) {
std::cerr << "\nColoring LR [CallInt=" << LR->isCallInterference() <<"]:";
printSet(*LR);
}
if (LR->hasSuggestedColor()) {
unsigned SugCol = LR->getSuggestedColor();
if (!IsColorUsedArr[SugCol]) {
if (LR->isSuggestedColorUsable()) {
// if the suggested color is volatile, we should use it only if
// there are no call interferences. Otherwise, it will get spilled.
if (DEBUG_RA)
std::cerr << "\n -Coloring with sug color: " << SugCol;
LR->setColor(LR->getSuggestedColor());
return;
} else if(DEBUG_RA) {
std::cerr << "\n Couldn't alloc Sug col - LR volatile & calls interf";
}
} else if (DEBUG_RA) { // can't allocate the suggested col
std::cerr << "\n Could NOT allocate the suggested color (already used) ";
printSet(*LR); std::cerr << "\n";
}
}
unsigned SearchStart; // start pos of color in pref-order
bool ColorFound= false; // have we found a color yet?
//if this Node is between calls
if (! LR->isCallInterference()) {
// start with volatiles (we can allocate volatiles safely)
SearchStart = SparcIntRegClass::StartOfAllRegs;
} else {
// start with non volatiles (no non-volatiles)
SearchStart = SparcIntRegClass::StartOfNonVolatileRegs;
}
unsigned c=0; // color
// find first unused color
for (c=SearchStart; c < SparcIntRegClass::NumOfAvailRegs; c++) {
if (!IsColorUsedArr[c]) {
ColorFound = true;
break;
}
}
if (ColorFound) {
LR->setColor(c); // first color found in preffered order
if (DEBUG_RA) std::cerr << "\n Colored after first search with col " << c;
}
// if color is not found because of call interference
// try even finding a volatile color and insert save across calls
//
else if (LR->isCallInterference()) {
// start from 0 - try to find even a volatile this time
SearchStart = SparcIntRegClass::StartOfAllRegs;
// find first unused volatile color
for(c=SearchStart; c < SparcIntRegClass::StartOfNonVolatileRegs; c++) {
if (! IsColorUsedArr[c]) {
ColorFound = true;
break;
}
}
if (ColorFound) {
LR->setColor(c);
// get the live range corresponding to live var
// since LR span across calls, must save across calls
//
LR->markForSaveAcrossCalls();
if (DEBUG_RA)
std::cerr << "\n Colored after SECOND search with col " << c;
}
}
// If we couldn't find a color regardless of call interference - i.e., we
// don't have either a volatile or non-volatile color left
//
if (!ColorFound)
LR->markForSpill(); // no color found - must spill
}
//-----------------------------------------------------------------------------
// Int CC Register Class - method for coloring a node in the interference graph.
//
// Algorithm:
//
// If (node has any interferences)
// /* all interference operations can use only one register! */
// mark the LR for spilling
// else {
// if (the LR is a 64-bit comparison) use %xcc
// else /*32-bit or smaller*/ use %icc
// }
//
// Note: The third name (%ccr) is essentially an assembly mnemonic and
// depends solely on the opcode, so the name can be chosen in EmitAssembly.
//-----------------------------------------------------------------------------
void SparcIntCCRegClass::colorIGNode(IGNode *Node,
const std::vector<bool> &IsColorUsedArr) const
{
if (Node->getNumOfNeighbors() > 0)
Node->getParentLR()->markForSpill();
// Mark the appropriate register in any case (even if it needs to be spilled)
// because there is only one possible register, but more importantly, the
// spill algorithm cannot find it. In particular, we have to choose
// whether to use %xcc or %icc based on type of value compared
//
const LiveRange* ccLR = Node->getParentLR();
const Type* setCCType = (* ccLR->begin())->getType(); // any Value in LR
assert(setCCType->isIntegral() || isa<PointerType>(setCCType));
int ccReg = ((isa<PointerType>(setCCType) || setCCType == Type::LongTy)
? xcc : icc);
#ifndef NDEBUG
// Let's just make sure values of two different types have not been
// coalesced into this LR.
for (ValueSet::const_iterator I=ccLR->begin(), E=ccLR->end(); I!=E; ++I) {
const Type* ccType = (*I)->getType();
assert((ccReg == xcc && (isa<PointerType>(ccType)
|| ccType == Type::LongTy)) ||
(ccReg == icc && ccType->isIntegral() && ccType != Type::LongTy)
&& "Comparisons needing different intCC regs coalesced in LR!");
}
#endif
Node->setColor(ccReg); // only one int cc reg is available
}
//-----------------------------------------------------------------------------
// Float Register Class - method for coloring a node in the interference graph.
//
// Algorithm:
//
// If the LR is a double try to allocate f32 - f63
// If the above fails or LR is single precision
// If the LR does not interfere with a call
// start allocating from f0
// Else start allocating from f6
// If a color is still not found because LR interferes with a call
// Search in f0 - f6. If found mark for spill across calls.
// If a color is still not fond, mark for spilling
//
//----------------------------------------------------------------------------
void SparcFloatRegClass::colorIGNode(IGNode * Node,
const std::vector<bool> &IsColorUsedArr) const
{
LiveRange *LR = Node->getParentLR();
#ifndef NDEBUG
// Check that the correct colors have been are marked for fp-doubles.
//
// FIXME: This is old code that is no longer needed. Temporarily converting
// it into a big assertion just to check that the replacement logic
// (invoking SparcFloatRegClass::markColorsUsed() directly from
// RegClass::colorIGNode) works correctly.
//
// In fact, this entire function should be identical to
// SparcIntRegClass::colorIGNode(), and perhaps can be
// made into a general case in CodeGen/RegAlloc/RegClass.cpp.
//
unsigned NumNeighbors = Node->getNumOfNeighbors(); // total # of neighbors
for(unsigned n=0; n < NumNeighbors; n++) { // for each neigh
IGNode *NeighIGNode = Node->getAdjIGNode(n);
LiveRange *NeighLR = NeighIGNode->getParentLR();
if (NeighLR->hasColor() &&
NeighLR->getType() == Type::DoubleTy) {
assert(IsColorUsedArr[ NeighLR->getColor() ] &&
IsColorUsedArr[ NeighLR->getColor()+1 ]);
} else if (NeighLR->hasSuggestedColor() &&
NeighLR-> isSuggestedColorUsable() ) {
// if the neighbour can use the suggested color
assert(IsColorUsedArr[ NeighLR->getSuggestedColor() ]);
if (NeighLR->getType() == Type::DoubleTy)
assert(IsColorUsedArr[ NeighLR->getSuggestedColor()+1 ]);
}
}
#endif
// **NOTE: We don't check for call interferences in allocating suggested
// color in this class since ALL registers are volatile. If this fact
// changes, we should change the following part
//- see SparcIntRegClass::colorIGNode()
//
if( LR->hasSuggestedColor() ) {
if( ! IsColorUsedArr[ LR->getSuggestedColor() ] ) {
LR->setColor( LR->getSuggestedColor() );
return;
} else if (DEBUG_RA) { // can't allocate the suggested col
std::cerr << " Could NOT allocate the suggested color for LR ";
printSet(*LR); std::cerr << "\n";
}
}
int ColorFound = -1; // have we found a color yet?
bool isCallInterf = LR->isCallInterference();
// if value is a double - search the double only region (f32 - f63)
// i.e. we try to allocate f32 - f63 first for doubles since singles
// cannot go there. By doing that, we provide more space for singles
// in f0 - f31
//
if (LR->getType() == Type::DoubleTy)
ColorFound = findFloatColor( LR, 32, 64, IsColorUsedArr );
if (ColorFound >= 0) { // if we could find a color
LR->setColor(ColorFound);
return;
} else {
// if we didn't find a color becuase the LR was single precision or
// all f32-f63 range is filled, we try to allocate a register from
// the f0 - f31 region
unsigned SearchStart; // start pos of color in pref-order
//if this Node is between calls (i.e., no call interferences )
if (! isCallInterf) {
// start with volatiles (we can allocate volatiles safely)
SearchStart = SparcFloatRegClass::StartOfAllRegs;
} else {
// start with non volatiles (no non-volatiles)
SearchStart = SparcFloatRegClass::StartOfNonVolatileRegs;
}
ColorFound = findFloatColor(LR, SearchStart, 32, IsColorUsedArr);
}
if (ColorFound >= 0) { // if we could find a color
LR->setColor(ColorFound);
return;
} else if (isCallInterf) {
// We are here because there is a call interference and no non-volatile
// color could be found.
// Now try to allocate even a volatile color
ColorFound = findFloatColor(LR, SparcFloatRegClass::StartOfAllRegs,
SparcFloatRegClass::StartOfNonVolatileRegs,
IsColorUsedArr);
}
if (ColorFound >= 0) {
LR->setColor(ColorFound); // first color found in prefered order
LR->markForSaveAcrossCalls();
} else {
// we are here because no color could be found
LR->markForSpill(); // no color found - must spill
}
}
//-----------------------------------------------------------------------------
// This method marks the registers used for a given register number.
// This marks a single register for Float regs, but the R,R+1 pair
// for double-precision registers.
//-----------------------------------------------------------------------------
void SparcFloatRegClass::markColorsUsed(unsigned RegInClass,
int UserRegType,
int RegTypeWanted,
std::vector<bool> &IsColorUsedArr) const
{
if (UserRegType == UltraSparcRegInfo::FPDoubleRegType ||
RegTypeWanted == UltraSparcRegInfo::FPDoubleRegType) {
// This register is used as or is needed as a double-precision reg.
// We need to mark the [even,odd] pair corresponding to this reg.
// Get the even numbered register corresponding to this reg.
unsigned EvenRegInClass = RegInClass & ~1u;
assert(EvenRegInClass+1 < NumOfAllRegs &&
EvenRegInClass+1 < IsColorUsedArr.size());
IsColorUsedArr[EvenRegInClass] = true;
IsColorUsedArr[EvenRegInClass+1] = true;
}
else {
assert(RegInClass < NumOfAllRegs && RegInClass < IsColorUsedArr.size());
assert(UserRegType == RegTypeWanted
&& "Something other than FP single/double types share a reg class?");
IsColorUsedArr[RegInClass] = true;
}
}
// This method finds unused registers of the specified register type,
// using the given "used" flag array IsColorUsedArr. It checks a single
// entry in the array directly for float regs, and checks the pair [R,R+1]
// for double-precision registers
// It returns -1 if no unused color is found.
//
int SparcFloatRegClass::findUnusedColor(int RegTypeWanted,
const std::vector<bool> &IsColorUsedArr) const
{
if (RegTypeWanted == UltraSparcRegInfo::FPDoubleRegType) {
unsigned NC = 2 * this->getNumOfAvailRegs();
assert(IsColorUsedArr.size() == NC && "Invalid colors-used array");
for (unsigned c = 0; c < NC; c+=2)
if (!IsColorUsedArr[c]) {
assert(!IsColorUsedArr[c+1] && "Incorrect used regs for FP double!");
return c;
}
return -1;
}
else
return TargetRegClassInfo::findUnusedColor(RegTypeWanted, IsColorUsedArr);
}
//-----------------------------------------------------------------------------
// Helper method for coloring a node of Float Reg class.
// Finds the first available color in the range [Start,End] depending on the
// type of the Node (i.e., float/double)
//-----------------------------------------------------------------------------
int SparcFloatRegClass::findFloatColor(const LiveRange *LR,
unsigned Start,
unsigned End,
const std::vector<bool> &IsColorUsedArr) const
{
if (LR->getType() == Type::DoubleTy) {
// find first unused color for a double
assert(Start % 2 == 0 && "Odd register number could be used for double!");
for (unsigned c=Start; c < End ; c+= 2)
if (!IsColorUsedArr[c]) {
assert(!IsColorUsedArr[c+1] &&
"Incorrect marking of used regs for Sparc FP double!");
return c;
}
} else {
// find first unused color for a single
for (unsigned c = Start; c < End; c++)
if (!IsColorUsedArr[c])
return c;
}
return -1;
}