mirrors/dynarmic
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

constant_propagation_pass: Add 64-bit variants of shifts to the pass

Browse source 
These optimizations can also apply to the 64-bit variants of the shift
opcodes; we just need to check if the instruction has an associated
pseudo-op before performing the 32-bit variant's specifics.

While we're at it, we can also relocate the code to its own function
like the rest of the cases to keep organization consistent.
This commit is contained in:
Lioncash 2018-10-12 05:21:51 -04:00 committed by MerryMage
parent 8bfaa9aac0
commit 07c197e8d0
1 changed files with 26 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

40
src/ir_opt/constant_propagation_pass.cpp
View file

@ -154,6 +154,26 @@ void FoldOR(IR::Inst& inst, bool is_32_bit) {
}
}
void FoldShifts(IR::Inst& inst) {
IR::Inst* carry_inst = inst.GetAssociatedPseudoOperation(IR::Opcode::GetCarryFromOp);
// The 32-bit variants can contain 3 arguments, while the
// 64-bit variants only contain 2.
if (inst.NumArgs() == 3 && !carry_inst) {
inst.SetArg(2, IR::Value(false));
}
const auto shift_amount = inst.GetArg(1);
if (!shift_amount.IsZero()) {
return;
}
if (carry_inst) {
carry_inst->ReplaceUsesWith(inst.GetArg(2));
}
inst.ReplaceUsesWith(inst.GetArg(0));
}
void FoldSignExtendXToWord(IR::Inst& inst) {
if (!inst.AreAllArgsImmediates()) {
return;
@ -197,23 +217,15 @@ void ConstantPropagation(IR::Block& block) {
switch (opcode) {
case IR::Opcode::LogicalShiftLeft32:
case IR::Opcode::LogicalShiftLeft64:
case IR::Opcode::LogicalShiftRight32:
case IR::Opcode::LogicalShiftRight64:
case IR::Opcode::ArithmeticShiftRight32:
case IR::Opcode::RotateRight32: {
if (!inst.GetAssociatedPseudoOperation(IR::Opcode::GetCarryFromOp)) {
inst.SetArg(2, IR::Value(false));
}
auto shift_amount = inst.GetArg(1);
if (shift_amount.IsImmediate() && shift_amount.GetU8() == 0) {
IR::Inst* carry_inst = inst.GetAssociatedPseudoOperation(IR::Opcode::GetCarryFromOp);
if (carry_inst) {
carry_inst->ReplaceUsesWith(inst.GetArg(2));
}
inst.ReplaceUsesWith(inst.GetArg(0));
}
case IR::Opcode::ArithmeticShiftRight64:
case IR::Opcode::RotateRight32:
case IR::Opcode::RotateRight64:
FoldShifts(inst);
break;
}
case IR::Opcode::Mul32:
case IR::Opcode::Mul64:
FoldMultiply(inst, opcode == IR::Opcode::Mul32);