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Fixed a problem with OptCmp3 that was in there for a while but is now

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triggered because of the new subtraction code sequence.


git-svn-id: svn://svn.cc65.org/cc65/trunk@4107 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-09-01 10:06:39 +00:00
parent 7c4240fe69
commit cdc3afa6ef
1 changed files with 31 additions and 53 deletions
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84
src/cc65/coptcmp.c
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@ -434,70 +434,48 @@ unsigned OptCmp3 (CodeSeg* S)
L[1]->OPC == OP65_CMP &&
CE_IsKnownImm (L[1], 0)) {
int Delete = 0;
/* Check for the call to boolxx. We only remove the compare if
* the carry flag is evaluated later, because the load will not
* set the carry flag.
*/
if (L[2]->OPC == OP65_JSR) {
switch (FindBoolCmpCond (L[2]->Arg)) {
switch (FindBoolCmpCond (L[2]->Arg)) {
case CMP_EQ:
case CMP_NE:
case CMP_GT:
case CMP_GE:
case CMP_LT:
case CMP_LE:
/* Remove the compare */
CS_DelEntry (S, I+1);
++Changes;
break;
case CMP_EQ:
case CMP_NE:
case CMP_GT:
case CMP_GE:
case CMP_LT:
case CMP_LE:
/* Remove the compare */
Delete = 1;
break;
case CMP_UGT:
case CMP_UGT:
case CMP_UGE:
case CMP_ULT:
case CMP_ULE:
case CMP_INV:
/* Leave it alone */
break;
}
case CMP_ULT:
case CMP_ULE:
case CMP_INV:
/* Leave it alone */
break;
}
} else {
} else if ((L[2]->Info & OF_FBRA) != 0) {
/* Check for a branch on conditions that are set by the load.
* Beware: The insn may branch to another conditional branch
* that evaluates other flags, so check that.
*/
CodeEntry* E = L[2];
int Delete = 0;
while (1) {
if ((E->Info & (OF_CBRA|OF_UBRA)) != 0) {
/* A conditional branch. Check if it jumps on a
* condition not set by the load.
*/
if ((E->Info & (OF_FBRA|OF_UBRA)) == 0) {
/* Invalid branch */
break;
} else if (E->JumpTo == 0) {
/* Jump to external */
Delete = 1;
break;
} else {
/* Check target of branch */
E = E->JumpTo->Owner;
}
} else {
/* Some other insn */
Delete = 1;
break;
}
}
/* The following insn branches on the condition of a load, so
* the compare instruction can be removed.
*/
Delete = 1;
/* Delete the compare if we can */
if (Delete) {
CS_DelEntry (S, I+1);
++Changes;
}
}
}
/* Delete the compare if we can */
if (Delete) {
CS_DelEntry (S, I+1);
++Changes;
}
}
/* Next entry */