diff --git a/src/cc65/coptcmp.c b/src/cc65/coptcmp.c index cd01c3b29..71dbfc624 100644 --- a/src/cc65/coptcmp.c +++ b/src/cc65/coptcmp.c @@ -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 */