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Remove even more transfer instructions.

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git-svn-id: svn://svn.cc65.org/cc65/trunk@4012 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-08-15 13:16:56 +00:00
parent 14f213cadb
commit fbe009a182
3 changed files with 165 additions and 1 deletions
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5
src/cc65/codeopt.c
View File

@ -1020,6 +1020,7 @@ static OptFunc DOptTest1 = { OptTest1, "OptTest1", 100, 0,
static OptFunc DOptTransfers1 = { OptTransfers1, "OptTransfers1", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptTransfers2 = { OptTransfers2, "OptTransfers2", 60, 0, 0, 0, 0, 0 };
static OptFunc DOptTransfers3 = { OptTransfers3, "OptTransfers3", 65, 0, 0, 0, 0, 0 };
static OptFunc DOptTransfers4 = { OptTransfers4, "OptTransfers4", 65, 0, 0, 0, 0, 0 };
static OptFunc DOptUnusedLoads = { OptUnusedLoads, "OptUnusedLoads", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptUnusedStores = { OptUnusedStores, "OptUnusedStores", 0, 0, 0, 0, 0, 0 };
@ -1097,6 +1098,7 @@ static OptFunc* OptFuncs[] = {
&DOptTransfers1,
&DOptTransfers2,
&DOptTransfers3,
&DOptTransfers4,
&DOptUnusedLoads,
&DOptUnusedStores,
};
@ -1427,7 +1429,8 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptDupLoads, 1);
C += RunOptFunc (S, &DOptStoreLoad, 1);
C += RunOptFunc (S, &DOptTransfers1, 1);
C += RunOptFunc (S, &DOptTransfers3, 1);
C += RunOptFunc (S, &DOptTransfers3, 1);
C += RunOptFunc (S, &DOptTransfers4, 1);
C += RunOptFunc (S, &DOptStore1, 1);
C += RunOptFunc (S, &DOptStore5, 1);
C += RunOptFunc (S, &DOptPushPop, 1);

156
src/cc65/coptind.c
View File

@ -1397,6 +1397,162 @@ unsigned OptTransfers3 (CodeSeg* S)
unsigned OptTransfers4 (CodeSeg* S)
/* Replace a load of a register followed by a transfer insn of the same register
* by a load of the second register if possible.
*/
{
unsigned Changes = 0;
unsigned Load = 0; /* Index of load insn */
unsigned Xfer = 0; /* Index of transfer insn */
CodeEntry* LoadEntry = 0; /* Pointer to load insn */
CodeEntry* XferEntry = 0; /* Pointer to xfer insn */
enum {
Searching,
FoundLoad,
FoundXfer
} State = Searching;
/* Walk over the entries. Look for a load instruction that is followed by
* a load later.
*/
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
switch (State) {
case Searching:
if (E->Info & OF_LOAD) {
/* Found start of sequence */
Load = I;
LoadEntry = E;
State = FoundLoad;
}
break;
case FoundLoad:
/* If we find a conditional jump, abort the sequence, since
* handling them makes things really complicated.
*/
if (E->Info & OF_CBRA) {
/* Switch back to searching */
I = Load;
State = Searching;
/* Does this insn use the target register of the load? */
} else if ((E->Use & LoadEntry->Chg) != 0) {
/* It it's a xfer instruction, and the block is a basic
* block, proceed. Otherwise restart
*/
if ((E->Info & OF_XFR) != 0 &&
CS_IsBasicBlock (S, Load, I)) {
Xfer = I;
XferEntry = E;
State = FoundXfer;
} else {
I = Load;
State = Searching;
}
/* Does this insn change the target register of the load? */
} else if (E->Chg & LoadEntry->Chg) {
/* We *may* add code here to remove the load, but I'm
* currently not sure about the consequences, so I won't
* do that and bail out instead.
*/
I = Load;
State = Searching;
}
break;
case FoundXfer:
/* We are at the instruction behind the xfer. If the register
* isn't used later, and we have an address mode match, we can
* replace the transfer by a load and remove the initial load.
*/
if ((GetRegInfo (S, I, LoadEntry->Chg) & LoadEntry->Chg) == 0 &&
(LoadEntry->AM == AM65_ABS || LoadEntry->AM == AM65_ZP) &&
!MemAccess (S, Load+1, Xfer-1, E->Arg)) {
/* Generate the replacement load insn */
CodeEntry* X = 0;
switch (XferEntry->OPC) {
case OP65_TXA:
case OP65_TYA:
X = NewCodeEntry (OP65_LDA,
LoadEntry->AM,
LoadEntry->Arg,
0,
LoadEntry->LI);
break;
case OP65_TAX:
X = NewCodeEntry (OP65_LDX,
LoadEntry->AM,
LoadEntry->Arg,
0,
LoadEntry->LI);
break;
case OP65_TAY:
X = NewCodeEntry (OP65_LDY,
LoadEntry->AM,
LoadEntry->Arg,
0,
LoadEntry->LI);
break;
default:
break;
}
/* If we have a replacement load, change the code */
if (X) {
/* Insert before the xfer insn */
CS_InsertEntry (S, X, Xfer);
/* Remove the xfer instead */
CS_DelEntry (S, Xfer+1);
/* Remove the initial load */
CS_DelEntry (S, Load);
/* Correct I so we continue with the next insn */
I -= 2;
/* Remember we had changes */
++Changes;
} else {
/* Restart after last xfer insn */
I = Xfer;
}
} else {
/* Restart after last xfer insn */
I = Xfer;
}
State = Searching;
break;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptPushPop (CodeSeg* S)
/* Remove a PHA/PLA sequence were A is not used later */
{

5
src/cc65/coptind.h
View File

@ -115,6 +115,11 @@ unsigned OptTransfers3 (CodeSeg* S);
* store of the first register if this is possible.
*/
unsigned OptTransfers4 (CodeSeg* S);
/* Replace a load of a register followed by a transfer insn of the same register
* by a load of the second register if possible.
*/
unsigned OptPushPop (CodeSeg* S);
/* Remove a PHA/PLA sequence were A is not used later */