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Add another form of duplicate load removal.

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git-svn-id: svn://svn.cc65.org/cc65/trunk@5778 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2012-07-10 20:46:21 +00:00
parent 7a0fa3ce67
commit 40a3084553
1 changed files with 63 additions and 0 deletions
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63
src/cc65/codeopt.c
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@ -224,6 +224,66 @@ static unsigned OptLoad2 (CodeSeg* S)
static unsigned OptLoad3 (CodeSeg* S)
/* Remove repeated loads from one and the same memory location */
{
unsigned Changes = 0;
CodeEntry* Load = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Forget a preceeding load if we have a label */
if (Load && CE_HasLabel (E)) {
Load = 0;
}
/* Check if this insn is a load */
if (E->Info & OF_LOAD) {
/* If we had a preceeding load that is identical, remove this one.
* If it is not identical, or we didn't have one, remember it.
*/
if (Load != 0 &&
E->OPC == Load->OPC &&
E->AM == Load->AM &&
((E->Arg == 0 && Load->Arg == 0) ||
strcmp (E->Arg, Load->Arg) == 0)) {
/* Now remove the call to the subroutine */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
/* Next insn */
continue;
} else {
Load = E;
}
} else if ((E->Info & OF_CMP) == 0 && (E->Info & OF_CBRA) == 0) {
/* Forget the first load on occurance of any insn we don't like */
Load = 0;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
/*****************************************************************************/
/* Decouple operations */
/*****************************************************************************/
@ -616,6 +676,7 @@ static OptFunc DOptJumpTarget2 = { OptJumpTarget2, "OptJumpTarget2", 100, 0,
static OptFunc DOptJumpTarget3 = { OptJumpTarget3, "OptJumpTarget3", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptLoad1 = { OptLoad1, "OptLoad1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptLoad2 = { OptLoad2, "OptLoad2", 200, 0, 0, 0, 0, 0 };
static OptFunc DOptLoad3 = { OptLoad3, "OptLoad3", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptNegAX1 = { OptNegAX1, "OptNegAX1", 165, 0, 0, 0, 0, 0 };
static OptFunc DOptNegAX2 = { OptNegAX2, "OptNegAX2", 200, 0, 0, 0, 0, 0 };
static OptFunc DOptRTS = { OptRTS, "OptRTS", 100, 0, 0, 0, 0, 0 };
@ -714,6 +775,7 @@ static OptFunc* OptFuncs[] = {
&DOptJumpTarget3,
&DOptLoad1,
&DOptLoad2,
&DOptLoad3,
&DOptNegAX1,
&DOptNegAX2,
&DOptPrecalc,
@ -1155,6 +1217,7 @@ static unsigned RunOptGroup4 (CodeSeg* S)
Changes += RunOptFunc (S, &DOptTest2, 1);
Changes += RunOptFunc (S, &DOptTransfers2, 1);
Changes += RunOptFunc (S, &DOptLoad2, 1);
Changes += RunOptFunc (S, &DOptLoad3, 1);
/* Return the number of changes */
return Changes;