Added optimizations for commutative arithmetic ops
git-svn-id: svn://svn.cc65.org/cc65/trunk@469 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz
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901a8088e6
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1 changed files with 207 additions and 111 deletions
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@ -177,6 +177,8 @@ static const struct {
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{ "\tstz\t", 0, REG_NONE, REG_NONE },
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{ "\ttax", 1, REG_A, REG_X },
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{ "\ttay", 1, REG_A, REG_Y },
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{ "\ttrb\t", 0, REG_A, REG_NONE },
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{ "\ttsb\t", 0, REG_A, REG_NONE },
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{ "\ttsx", 1, REG_NONE, REG_X },
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{ "\ttxa", 1, REG_X, REG_A },
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{ "\ttya", 1, REG_Y, REG_A },
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@ -3304,7 +3306,7 @@ static void OptTests (void)
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{
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Line* L2 [2];
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const char* BitOps [] = {
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static const char* BitOps [] = {
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"\tand\t",
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"\tora\t",
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"\teor\t",
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@ -3401,6 +3403,127 @@ static void OptTests (void)
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static void OptBitOps (void)
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/* Optimize bit oeprations */
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{
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Line* L2 [2];
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/* Walk over the code */
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Line* L = FirstCode;
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while (L) {
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/* Search for
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*
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* lda xxx
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* and #$yy ; adc/eor/ora
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* sta xxx
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*
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* and replace it by
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*
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* lda #$yy
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* and xxx
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* sta xxx
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*
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* While this saves nothing here, it transforms the code to contain an
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* explicit register load that may be removed by the basic block
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* optimization later. As a special optimization for the 65C02, the
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* "ora" and "and" ops may be replaced by "trb" and "tsb" resp. if the
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* value in A is not used later.
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*/
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if (LineMatch (L, "\tlda\t") &&
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L->Line[5] != '#' &&
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GetNextCodeLines (L, L2, 2) &&
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LineMatch (L2[1], "\tsta\t") &&
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strcmp (L->Line+5, L2[1]->Line+5) == 0) {
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if (LineMatch (L2[0], "\tand\t#$")) {
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unsigned Val = GetHexNum (L2[0]->Line+7);
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if (Val == 0x00) {
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/* AND with 0x00, remove the mem access */
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FreeLine (L);
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FreeLine (L2[1]);
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/* Replace the AND by a load */
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L = ReplaceLine (L2[0], "\tlda\t#$%02X", Val);
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} else if (Val == 0xFF) {
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/* AND with 0xFF, just load the value from memory */
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FreeLines (L2[0], L2[1]);
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} else if (CPU == CPU_65C02 &&
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!IsXAddrMode (L) &&
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!IsYAddrMode (L) &&
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!RegAUsed (L2[1])) {
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/* Replace by trb */
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ReplaceLine (L, "\tlda\t#$%02X", (~Val) & 0xFF);
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ReplaceLine (L2[0], "\ttrb\t%s", L2[1]->Line+5);
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FreeLine (L2[1]);
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L = L2[0];
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} else {
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/* Just reorder */
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L = ReplaceLine (L, "\tlda\t#$%02X", Val);
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ReplaceLine (L2[0], "\tand\t%s", L2[1]->Line+5);
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L = L2[1];
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}
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} else if (LineMatch (L2[0], "\tora\t#$")) {
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unsigned Val = GetHexNum (L2[0]->Line+7);
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if (Val == 0x00) {
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/* ORA with 0x00, just load the value from memory */
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FreeLines (L2[0], L2[1]);
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} else if (Val == 0xFF) {
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/* ORA with 0xFF, replace by a store of $FF */
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FreeLine (L);
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ReplaceLine (L2[0], "\tlda\t#$FF");
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} else if (CPU == CPU_65C02 &&
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!IsXAddrMode (L) &&
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!IsYAddrMode (L) &&
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!RegAUsed (L2[1])) {
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/* Replace by trb */
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ReplaceLine (L, "\tlda\t#$%02X", Val);
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ReplaceLine (L2[0], "\ttsb\t%s", L2[1]->Line+5);
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FreeLine (L2[1]);
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L = L2[0];
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} else {
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/* Just reorder */
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L = ReplaceLine (L, "\tlda\t#$%02X", Val);
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ReplaceLine (L2[0], "\tora\t%s", L2[1]->Line+5);
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L = L2[1];
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}
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} else if (LineMatch (L2[0], "\teor\t#$") ||
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LineMatch (L2[0], "\tadc\t#$")) {
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/* Just reorder */
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L = ReplaceLine (L, "\tlda\t%s", L2[0]->Line+5);
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ReplaceLine (L2[0], "\t%.3s\t%s", L2[0]->Line+1, L2[1]->Line+5);
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}
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}
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/* Next line */
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L = NextCodeLine (L);
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}
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}
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static void OptNeg (void)
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/* Optimize the "bnegax/jeq" and "bnegax/jne" sequences */
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{
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@ -4268,21 +4391,37 @@ static void OptRTS (void)
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static void OptOnePass (unsigned long Flag, void (*F) (void))
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/* Call one optimizer pass if enabled */
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{
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if ((OptDisable & Flag) == 0) {
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F ();
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} else if (Verbose || Debug) {
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printf ("Optimizer pass %04lX skipped\n", Flag);
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}
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}
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void OptDoOpt (void)
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/* Run the optimizer over the collected stuff */
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{
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typedef void (*OptFunc)(void);
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/* Table with optimizer steps - are called in this order */
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static const OptFunc OptFuncs [] = {
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OptCompares1, /* Optimize compares - first step */
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OptDeadJumps, /* Remove dead jumps */
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OptLoads, /* Remove unnecessary loads */
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OptRegLoads, /* Remove unnecessary register loads */
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OptPtrOps, /* Optimize stores through pointers */
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OptRegVars, /* Optimize use of register variables */
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OptDoubleJumps, /* Remove jump cascades - must be used before OptNeg */
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OptNeg, /* Remove unnecessary boolean negates */
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OptJumpRTS, /* Replace jumps to an RTS by an RTS */
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OptBoolTransforms, /* Optimize boolean transforms */
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OptCompares2, /* Optimize compares */
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OptTests, /* Remove unnecessary tests */
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OptBitOps, /* Optimize bit operations */
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OptTriples, /* Optimize several triples */
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OptBlocks, /* Optimize basic blocks */
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OptRegLoads, /* Remove unnecessary register loads (another pass) */
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OptBlocks, /* Optimize basic blocks */
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OptJumps, /* Optimize jumps */
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OptRTS, /* Optimize jsr/rts sequences */
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};
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unsigned long Flags;
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unsigned I;
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/* Find and remember the first line of code */
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FindCodeStart ();
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@ -4293,57 +4432,14 @@ void OptDoOpt (void)
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CreateLabelList ();
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/* Ok, now start the real optimizations */
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/* Optimize compares - first step */
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OptOnePass (0x0001, OptCompares1);
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/* Remove dead jumps */
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OptOnePass (0x0002, OptDeadJumps);
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/* Remove unnecessary loads */
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OptOnePass (0x0004, OptLoads);
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/* Remove unnecessary register loads */
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OptOnePass (0x0008, OptRegLoads);
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/* Optimize stores through pointers */
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OptOnePass (0x0010, OptPtrOps);
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/* Optimize use of register variables */
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OptOnePass (0x0020, OptRegVars);
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/* Remove jump cascades - must be used before OptNeg */
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OptOnePass (0x0040, OptDoubleJumps);
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/* Remove unnecessary boolean negates */
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OptOnePass (0x0080, OptNeg);
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/* Replace jumps to an RTS by an RTS */
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OptOnePass (0x0100, OptJumpRTS);
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/* Optimize boolean transforms */
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OptOnePass (0x0200, OptBoolTransforms);
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/* Optimize compares */
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OptOnePass (0x0400, OptCompares2);
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/* Remove unnecessary tests */
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OptOnePass (0x0800, OptTests);
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/* Optimize several triples */
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OptOnePass (0x1000, OptTriples);
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/* Optimize basic blocks */
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OptOnePass (0x2000, OptBlocks);
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/* Remove unnecessary register loads (another pass) */
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OptOnePass (0x0008, OptRegLoads);
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/* Optimize jumps */
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OptOnePass (0x4000, OptJumps);
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/* Optimize jsr/rts sequences */
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OptOnePass (0x8000, OptRTS);
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Flags = 1UL;
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for (I = 0; I < sizeof(OptFuncs)/sizeof(OptFuncs[0]); ++I) {
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if ((OptDisable & Flags) == 0) {
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OptFuncs[I] ();
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} else if (Verbose || Debug) {
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printf ("Optimizer pass %u skipped\n", I);
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}
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}
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}
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