/**
* Tries to replace an instruction with a const instruction. The given instruction must have a
* constant result for it to be replaced.
*
* @param insn {@code non-null;} instruction to try to replace
* @return true if the instruction was replaced
*/
private boolean tryReplacingWithConstant(NormalSsaInsn insn) {
Insn originalRopInsn = insn.getOriginalRopInsn();
Rop opcode = originalRopInsn.getOpcode();
RegisterSpec result = insn.getResult();
if (result != null && !ssaMeth.isRegALocal(result) && opcode.getOpcode() != RegOps.CONST) {
TypeBearer type = insn.getResult().getTypeBearer();
if (type.isConstant() && type.getBasicType() == Type.BT_INT) {
// Replace the instruction with a constant
replacePlainInsn(insn, RegisterSpecList.EMPTY, RegOps.CONST, (Constant) type);
// Remove the source as well if this is a move-result-pseudo
if (opcode.getOpcode() == RegOps.MOVE_RESULT_PSEUDO) {
int pred = insn.getBlock().getPredecessors().nextSetBit(0);
ArrayList<SsaInsn> predInsns = ssaMeth.getBlocks().get(pred).getInsns();
NormalSsaInsn sourceInsn = (NormalSsaInsn) predInsns.get(predInsns.size() - 1);
replacePlainInsn(sourceInsn, RegisterSpecList.EMPTY, RegOps.GOTO, null);
}
return true;
}
}
return false;
}
