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New optimization step

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git-svn-id: svn://svn.cc65.org/cc65/trunk@4278 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-09-29 18:46:25 +00:00
parent 0b4c486a49
commit c2b03e0208
3 changed files with 110 additions and 27 deletions
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5
src/cc65/codeopt.c
View File

@ -447,7 +447,7 @@ static unsigned OptShift4 (CodeSeg* S)
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
++Changes;
}
NextEntry:
@ -1110,6 +1110,7 @@ static OptFunc DOptIndLoads2 = { OptIndLoads2, "OptIndLoads2", 0, 0,
static OptFunc DOptJumpCascades = { OptJumpCascades, "OptJumpCascades", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptJumpTarget1 = { OptJumpTarget1, "OptJumpTarget1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptJumpTarget2 = { OptJumpTarget2, "OptJumpTarget2", 100, 0, 0, 0, 0, 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 DOptRTS = { OptRTS, "OptRTS", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptRTSJumps1 = { OptRTSJumps1, "OptRTSJumps1", 100, 0, 0, 0, 0, 0 };
@ -1198,6 +1199,7 @@ static OptFunc* OptFuncs[] = {
&DOptJumpCascades,
&DOptJumpTarget1,
&DOptJumpTarget2,
&DOptJumpTarget3,
&DOptLoad1,
&DOptNegA1,
&DOptNegA2,
@ -1568,6 +1570,7 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptBoolTrans, 1);
C += RunOptFunc (S, &DOptJumpTarget1, 1);
C += RunOptFunc (S, &DOptJumpTarget2, 1);
C += RunOptFunc (S, &DOptJumpTarget3, 1);
C += RunOptFunc (S, &DOptCondBranches1, 1);
C += RunOptFunc (S, &DOptCondBranches2, 1);
C += RunOptFunc (S, &DOptRTSJumps1, 1);

126
src/cc65/coptind.c
View File

@ -183,8 +183,7 @@ static short ZPRegVal (unsigned short Use, const RegContents* RC)
}
#if 0 /* Currently unused */
static short RegVal (unsigned short Use, const RegContents* RC)
/* Return the contents of the given register */
{
@ -198,7 +197,6 @@ static short RegVal (unsigned short Use, const RegContents* RC)
return ZPRegVal (Use, RC);
}
}
#endif
@ -750,6 +748,82 @@ NextEntry:
unsigned OptJumpTarget3 (CodeSeg* S)
/* Jumps to load instructions of a register, that do already have the matching
* register contents may skip the load instruction, since it's job is already
* done.
*/
{
unsigned Changes = 0;
unsigned I;
/* Generate register info for this step */
CS_GenRegInfo (S);
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned J, K;
CodeEntry* N;
/* New jump label */
CodeLabel* LN = 0;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if this is a load insn with a label */
if ((E->Info & OF_LOAD) != 0 &&
CE_IsConstImm (E) &&
CE_HasLabel (E) &&
(N = CS_GetNextEntry (S, I)) != 0) {
/* Walk over all insn that jump here */
for (J = 0; J < CE_GetLabelCount (E); ++J) {
/* Get the label */
CodeLabel* L = CE_GetLabel (E, J);
for (K = 0; K < CL_GetRefCount (L); ++K) {
/* Get the entry that jumps here */
CodeEntry* Jump = CL_GetRef (L, K);
/* Get the register info from this insn */
short Val = RegVal (E->Chg, &Jump->RI->Out2);
/* Check if the outgoing value is the one thatr's loaded */
if (Val == (unsigned char) E->Num) {
/* Ok, skip the insn. First, generate a label */
if (LN == 0) {
LN = CS_GenLabel (S, N);
}
/* Change the jump target to point to this new label */
CS_MoveLabelRef (S, Jump, LN);
/* Remember that we had changes */
++Changes;
}
}
}
}
/* Next entry */
++I;
}
/* Free register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}
/*****************************************************************************/
/* Optimize conditional branches */
/*****************************************************************************/
@ -1076,7 +1150,7 @@ unsigned OptDupLoads (CodeSeg* S)
break;
case OP65_STA:
/* If we store into a known zero page location, and this
/* If we store into a known zero page location, and this
* location does already contain the value to be stored,
* remove the store.
*/
@ -1129,7 +1203,7 @@ unsigned OptDupLoads (CodeSeg* S)
* that in the A register, replace the store by a STA. The
* optimizer will then remove the load instruction for Y
* later. If replacement by A is not possible try a
* replacement by X, but check for invalid addressing modes
* replacement by X, but check for invalid addressing modes
* in this case.
*/
} else if (RegValIsKnown (In->RegY)) {
@ -1182,39 +1256,39 @@ unsigned OptDupLoads (CodeSeg* S)
!CE_UseLoadFlags (N)) {
/* Value is identical and not followed by a branch */
Delete = 1;
}
break;
}
break;
case OP65_TYA:
case OP65_TYA:
if (RegValIsKnown (In->RegY) &&
In->RegY == In->RegA &&
(N = CS_GetNextEntry (S, I)) != 0 &&
(N = CS_GetNextEntry (S, I)) != 0 &&
!CE_UseLoadFlags (N)) {
/* Value is identical and not followed by a branch */
Delete = 1;
}
break;
/* Value is identical and not followed by a branch */
Delete = 1;
}
break;
default:
break;
default:
break;
}
}
/* Delete the entry if requested */
if (Delete) {
/* Delete the entry if requested */
if (Delete) {
/* Register value is not used, remove the load */
CS_DelEntry (S, I);
/* Register value is not used, remove the load */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
/* Remember, we had changes */
++Changes;
} else {
} else {
/* Next entry */
++I;
/* Next entry */
++I;
}
}
}

6
src/cc65/coptind.h
View File

@ -89,6 +89,12 @@ unsigned OptJumpTarget2 (CodeSeg* S);
* it's job is already done.
*/
unsigned OptJumpTarget3 (CodeSeg* S);
/* Jumps to load instructions of a register, that do already have the matching
* register contents may skip the load instruction, since it's job is already
* done.
*/
unsigned OptCondBranches1 (CodeSeg* S);
/* If an immidiate load of a register is followed by a conditional jump that
* is never taken because the load of the register sets the flags in such a