Added comments and correct logic for finding register sizes.
llvm-svn: 1494
diff --git a/llvm/lib/Target/Sparc/SparcRegClassInfo.cpp b/llvm/lib/Target/Sparc/SparcRegClassInfo.cpp
index f79dd58..6b39d61 100644
--- a/llvm/lib/Target/Sparc/SparcRegClassInfo.cpp
+++ b/llvm/lib/Target/Sparc/SparcRegClassInfo.cpp
@@ -4,23 +4,20 @@
#include "llvm/Target/Sparc.h"
//-----------------------------------------------------------------------------
-// Int Register Class
+// 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, bool IsColorUsedArr[]) const
{
-
- /* 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.
-
- */
-
LiveRange * LR = Node->getParentLR();
unsigned NumNeighbors = Node->getNumOfNeighbors(); // total # of neighbors
@@ -37,7 +34,6 @@
if( NeighLR-> isSuggestedColorUsable() )
IsColorUsedArr[ NeighLR->getSuggestedColor() ] = true;
}
-
}
if( DEBUG_RA ) {
@@ -49,8 +45,6 @@
unsigned SugCol = LR->getSuggestedColor();
- // cout << "\n -Has sug color: " << SugCol;
-
if( ! IsColorUsedArr[ SugCol ] ) {
if( LR->isSuggestedColorUsable() ) {
@@ -102,6 +96,7 @@
// 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
@@ -116,16 +111,16 @@
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) cout << "\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
@@ -141,61 +136,23 @@
//-----------------------------------------------------------------------------
-// Float Register Class
-//-----------------------------------------------------------------------------
-
-// find 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 *const LR,
- unsigned Start,
- unsigned End,
- bool IsColorUsedArr[] ) const
-{
-
- bool ColorFound = false;
- unsigned c;
-
- if( LR->getTypeID() == Type::DoubleTyID ) {
-
- // find first unused color for a double
- for( c=Start; c < End ;c+= 2){
- if( ! IsColorUsedArr[ c ] && ! IsColorUsedArr[ c+1 ])
- { ColorFound=true; break; }
- }
-
- } else {
-
- // find first unused color for a single
- for( c=Start; c < End; c++) {
- if( ! IsColorUsedArr[ c ] ) { ColorFound=true; break; }
- }
- }
-
- if( ColorFound ) return c;
- else return -1;
-}
-
-
-
-
-
+// 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,bool IsColorUsedArr[]) const
{
- /* 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
- */
-
-
LiveRange * LR = Node->getParentLR();
unsigned NumNeighbors = Node->getNumOfNeighbors(); // total # of neighbors
@@ -245,17 +202,24 @@
bool isCallInterf = LR->isCallInterference();
// if value is a double - search the double only reigon (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->getTypeID() == Type::DoubleTyID )
ColorFound = findFloatColor( LR, 32, 64, IsColorUsedArr );
- if( ColorFound >= 0 ) {
+ if( ColorFound >= 0 ) { // if we could find a color
LR->setColor(ColorFound);
if( DEBUG_RA) UltraSparcRegInfo::printReg( LR );
return;
}
+ else {
- else { // the above fails or LR is single precision
+ // 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
@@ -270,16 +234,15 @@
}
ColorFound = findFloatColor( LR, SearchStart, 32, IsColorUsedArr );
-
}
- if( ColorFound >= 0 ) {
+
+
+ if( ColorFound >= 0 ) { // if we could find a color
LR->setColor(ColorFound);
if( DEBUG_RA) UltraSparcRegInfo::printReg( LR );
return;
}
-
-
else if( isCallInterf ) {
// We are here because there is a call interference and no non-volatile
@@ -306,11 +269,43 @@
LR->markForSpill(); // no color found - must spill
if( DEBUG_RA) UltraSparcRegInfo::printReg( LR );
-
}
+//-----------------------------------------------------------------------------
+// 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 *const LR,
+ unsigned Start,
+ unsigned End,
+ bool IsColorUsedArr[] ) const {
+
+ bool ColorFound = false;
+ unsigned c;
+
+ if( LR->getTypeID() == Type::DoubleTyID ) {
+
+ // find first unused color for a double
+ for( c=Start; c < End ;c+= 2){
+ if( ! IsColorUsedArr[ c ] && ! IsColorUsedArr[ c+1 ])
+ { ColorFound=true; break; }
+ }
+
+ } else {
+
+ // find first unused color for a single
+ for( c=Start; c < End; c++) {
+ if( ! IsColorUsedArr[ c ] ) { ColorFound=true; break; }
+ }
+ }
+
+ if( ColorFound ) return c;
+ else return -1;
+}
+