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Merge pull request #408 from lioncash/shift

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constant_propagation_pass: Add 64-bit variants of shifts to the pass
This commit is contained in:
Merry 2018-10-12 20:22:29 +01:00 committed by MerryMage
commit 85bc96a61c
1 changed files with 26 additions and 14 deletions
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40
src/ir_opt/constant_propagation_pass.cpp
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@ -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);