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Optimize out flag-fixing code followed by ldy

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This commit is contained in:
Jason Turner 2021-05-25 18:56:10 -06:00
parent cc08629435
commit 13dbaafbfd
2 changed files with 9 additions and 25 deletions
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17
include/optimizer.hpp
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@ -177,9 +177,8 @@ bool optimize_redundant_lda(std::span<mos6502> &block, const Personality &person
// look for a literal or virtual register load into A
// that is redundant later
for (auto itr = block.begin(); itr != block.end(); ++itr) {
if (itr->opcode == mos6502::OpCode::lda &&
(itr->op.value.starts_with('#')
|| is_virtual_register_op(*itr, personality))) {
if (itr->opcode == mos6502::OpCode::lda
&& (itr->op.value.starts_with('#') || is_virtual_register_op(*itr, personality))) {
for (auto inner = std::next(itr); inner != block.end(); ++inner) {
if (is_opcode(*inner,
mos6502::OpCode::tay,
@ -257,9 +256,9 @@ bool optimize(std::vector<mos6502> &instructions, [[maybe_unused]] const Persona
// it might make sense in the future to only insert these if determined they are needed?
for (size_t op = 10; op < instructions.size(); ++op) {
if (instructions[op].opcode == mos6502::OpCode::lda || instructions[op].opcode == mos6502::OpCode::bcc
|| instructions[op].opcode == mos6502::OpCode::bcs) {
if (instructions[op - 1].text == "; END remove if next is lda, bcc, bcs"
|| (instructions[op - 2].text == "; END remove if next is lda, bcc, bcs"
|| instructions[op].opcode == mos6502::OpCode::bcs || instructions[op].opcode == mos6502::OpCode::ldy) {
if (instructions[op - 1].text == "; END remove if next is lda, bcc, bcs, ldy"
|| (instructions[op - 2].text == "; END remove if next is lda, bcc, bcs, ldy"
&& instructions[op - 1].type == ASMLine::Type::Directive)) {
for (size_t inner_op = op - 1; inner_op > 1; --inner_op) {
instructions[inner_op] =
@ -284,9 +283,9 @@ bool optimize(std::vector<mos6502> &instructions, [[maybe_unused]] const Persona
bool block_optimized = false;
for (auto &block : get_optimizable_blocks(instructions)) {
block_optimized = block_optimized || optimize_redundant_lda_after_sta(block) || optimize_dead_sta(block, personality) || optimize_dead_tax(block)
|| optimize_redundant_ldy(block) || optimize_redundant_lda(block, personality);
block_optimized = block_optimized || optimize_redundant_lda_after_sta(block)
|| optimize_dead_sta(block, personality) || optimize_dead_tax(block)
|| optimize_redundant_ldy(block) || optimize_redundant_lda(block, personality);
}
return block_optimized;
}

17
src/6502-c++.cpp
View File

@ -289,7 +289,7 @@ void fixup_16_bit_N_Z_flags(std::vector<mos6502> &instructions)
// if low order byte is negative, just load 1, this will properly set the Z flag and leave C correct
instructions.emplace_back(mos6502::OpCode::lda, Operand(Operand::Type::literal, "#1"));
instructions.emplace_back(ASMLine::Type::Label, set_flag_label);
instructions.emplace_back(ASMLine::Type::Directive, "; END remove if next is lda, bcc, bcs");
instructions.emplace_back(ASMLine::Type::Directive, "; END remove if next is lda, bcc, bcs, ldy");
}
void add_16_bit(const Personality &personality, std::vector<mos6502> &instructions, int reg, const std::string_view value)
@ -1174,21 +1174,6 @@ int main(const int argc, const char **argv)
disabled_optimizations += " -fvect-cost-model=cheap";
disabled_optimizations += " -fno-version-loops-for-strides";
*/
// disabled_optimizations += " -fgcse-after-reload";
// disabled_optimizations += " -fipa-cp-clone";
// disabled_optimizations += " -floop-interchange";
// disabled_optimizations += " -floop-unroll-and-jam";
// disabled_optimizations += " -fpeel-loops";
// disabled_optimizations += " -fpredictive-commoning";
// disabled_optimizations += " -fsplit-loops";
// disabled_optimizations += " -fsplit-paths";
// disabled_optimizations += " -ftree-loop-distribution";
// disabled_optimizations += " -ftree-loop-vectorize";
// disabled_optimizations += " -ftree-partial-pre";
// disabled_optimizations += " -ftree-slp-vectorize";
// disabled_optimizations += " -funswitch-loops";
// disabled_optimizations += " -fvect-cost-model=dynamic";
// disabled_optimizations += " -fversion-loops-for-strides";
const std::string gcc_command = fmt::format(
"avr-gcc -fverbose-asm -c -o {outfile} -S {warning_flags} -std=c++20 -mtiny-stack "