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Optimize lda/sta/lda and friends

This commit is contained in:
Colin Leroy-Mira 2023-11-12 22:35:24 +01:00
parent 9242508abf
commit 076137f41b
3 changed files with 60 additions and 0 deletions
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3
src/cc65/codeopt.c
View File

@ -197,6 +197,7 @@ static OptFunc DOptStore3 = { OptStore3, "OptStore3", 120, 0,
static OptFunc DOptStore4 = { OptStore4, "OptStore4", 50, 0, 0, 0, 0, 0 };
static OptFunc DOptStore5 = { OptStore5, "OptStore5", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptStoreLoad = { OptStoreLoad, "OptStoreLoad", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptLoadStoreLoad= { OptLoadStoreLoad,"OptLoadStoreLoad", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptSub1 = { OptSub1, "OptSub1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptSub2 = { OptSub2, "OptSub2", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptSub3 = { OptSub3, "OptSub3", 100, 0, 0, 0, 0, 0 };
@ -307,6 +308,7 @@ static OptFunc* OptFuncs[] = {
&DOptStore4,
&DOptStore5,
&DOptStoreLoad,
&DOptLoadStoreLoad,
&DOptSub1,
&DOptSub2,
&DOptSub3,
@ -723,6 +725,7 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptUnusedStores, 1);
C += RunOptFunc (S, &DOptDupLoads, 1);
C += RunOptFunc (S, &DOptStoreLoad, 1);
C += RunOptFunc (S, &DOptLoadStoreLoad, 1);
C += RunOptFunc (S, &DOptTransfers1, 1);
C += RunOptFunc (S, &DOptTransfers3, 1);
C += RunOptFunc (S, &DOptTransfers4, 1);

54
src/cc65/coptind.c
View File

@ -581,6 +581,60 @@ unsigned OptStoreLoad (CodeSeg* S)
unsigned OptLoadStoreLoad (CodeSeg* S)
/* Search for the sequence
**
** ld. xx
** st. yy
** ld. xx
**
** and remove the useless load.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[3];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if ((L[0]->OPC == OP65_LDA ||
L[0]->OPC == OP65_LDX ||
L[0]->OPC == OP65_LDY) &&
(L[0]->AM == AM65_ABS || L[0]->AM == AM65_ZP) &&
!CS_RangeHasLabel (S, I+1, 3) &&
CS_GetEntries (S, L+1, I+1, 2) &&
(L[1]->OPC == OP65_STA ||
L[1]->OPC == OP65_STX ||
L[1]->OPC == OP65_STY) &&
L[2]->OPC == L[0]->OPC &&
L[2]->AM == L[0]->AM &&
strcmp (L[0]->Arg, L[2]->Arg) == 0) {
/* Remove the second load */
CS_DelEntries (S, I+2, 1);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptTransfers1 (CodeSeg* S)
/* Remove transfers from one register to another and back */
{

3
src/cc65/coptind.h
View File

@ -64,6 +64,9 @@ unsigned OptDupLoads (CodeSeg* S);
unsigned OptStoreLoad (CodeSeg* S);
/* Remove a store followed by a load from the same location. */
unsigned OptLoadStoreLoad (CodeSeg* S);
/* Remove a load, store followed by a reload of the same location. */
unsigned OptTransfers1 (CodeSeg* S);
/* Remove transfers from one register to another and back */