MWCC/compiler_and_linker/unsorted/AddPropagation.c

#include "compiler/AddPropagation.h"
#include "compiler/Alias.h"
#include "compiler/BitVectors.h"
#include "compiler/CopyPropagation.h"
#include "compiler/PCode.h"
#include "compiler/PCodeInfo.h"
#include "compiler/Registers.h"
#include "compiler/StackFrame.h"
#include "compiler/CError.h"
#include "compiler/CParser.h"
#include "compiler/objects.h"

int propagatedadds;

static int is_add(PCode *instr) {
    return
    (
        instr->op == PC_ADD ||
        (
            instr->op == PC_ADDI &&
            (
                instr->args[2].kind == PCOp_IMMEDIATE ||
                (instr->args[2].kind == PCOp_MEMORY && (PCOpMemoryArg) instr->args[2].arg == PCOpMemory1)
            )
        )
    )
    &&
    instr->args[0].data.reg.reg >= n_real_registers[instr->args[0].arg];
}

static int addpropagatestouse(int candidateID, int useID) {
    int reg2;
    PCode *candidateInstr;
    PCode *useInstr;
    int reg1;
    int reg27;
    Object *object;
    SInt32 offset;
    int i;
    PCode *instr;
    PCodeArg *op;

    candidateInstr = Candidates[candidateID].pcode;
    useInstr = Uses[useID].pcode;
    reg1 = candidateInstr->args[0].data.reg.reg;
    reg2 = candidateInstr->args[1].data.reg.reg;
    reg27 = reg2;

    if (!useInstr->block) {
        recursive_propagation = 1;
        return 0;
    }

    if (useInstr->flags & (fIsRead | fIsWrite)) {
        if (PCODE_FLAG_SET_F(useInstr) & fUpdatesPtr)
            return 0;
    } else if (useInstr->op == PC_ADDI) {
        if (useInstr->args[2].kind != PCOp_IMMEDIATE)
            return 0;
    } else if (useInstr->op != PC_MR) {
        return 0;
    }

    if (candidateInstr->op == PC_ADD) {
        if (useInstr->argCount < 3) {
            if (useInstr->op != PC_MR)
                return 0;
        } else if (useInstr->args[2].kind == PCOp_IMMEDIATE) {
            if (useInstr->args[2].data.imm.value != 0)
                return 0;
        } else if (useInstr->args[2].kind == PCOp_REGISTER) {
            if (
                useInstr->args[1].kind != PCOp_REGISTER ||
                useInstr->args[2].data.reg.reg != reg1 ||
                useInstr->args[1].data.reg.reg != 0
                )
                return 0;
        } else {
            return 0;
        }

        object = NULL;
        offset = 0;
        if (candidateInstr->alias && candidateInstr->alias->type == AliasType0) {
            object = candidateInstr->alias->object;
            offset = candidateInstr->alias->offset;
        }
        reg27 = candidateInstr->args[2].data.reg.reg;
    } else if (candidateInstr->op == PC_ADDI) {
        if (candidateInstr->alias && candidateInstr->alias->type == AliasType0) {
            object = candidateInstr->alias->object;
            offset = candidateInstr->alias->offset;
        } else if (candidateInstr->args[2].kind == PCOp_MEMORY) {
            object = candidateInstr->args[2].data.mem.obj;
            offset = candidateInstr->args[2].data.mem.offset;
        } else if (candidateInstr->args[2].kind == PCOp_IMMEDIATE) {
            object = NULL;
            offset = candidateInstr->args[2].data.imm.value;
        } else {
            return 0;
        }

        if (useInstr->argCount < 3) {
            if (useInstr->op != PC_MR)
                return 0;
        } else if (useInstr->args[2].kind == PCOp_IMMEDIATE) {
            offset += useInstr->args[2].data.imm.value;
            if (object) {
                if (object->datatype == DLOCAL) {
                    if (!can_add_displ_to_local(object, offset))
                        return 0;
                } else {
                    return 0;
                }
            } else if (!FITS_IN_SHORT(offset)) {
                return 0;
            }
        } else {
            return 0;
        }
    } else {
        CError_FATAL(225);
        return 0;
    }

    if (
        (useInstr->flags & fIsWrite) &&
        useInstr->args[0].kind == PCOp_REGISTER &&
        useInstr->args[0].arg == RegClass_GPR &&
        useInstr->args[0].data.reg.reg == reg1
        )
        return 0;

    if (useInstr->args[1].data.reg.reg != reg1)
        return 0;

    if (candidateInstr->block == useInstr->block && precedes(candidateInstr, useInstr)) {
        for (instr = candidateInstr->nextPCode; instr && instr != useInstr; instr = instr->nextPCode) {
            op = instr->args;
            i = instr->argCount;
            while (i--) {
                if (
                    PC_OP_IS_WRITE_ANY_REGISTER(op, RegClass_GPR) &&
                    (op->data.reg.reg == reg2 || op->data.reg.reg == reg27)
                    )
                    return 0;
                op++;
            }
        }
    } else {
        if (!bitvectorgetbit(candidateID, propinfo[useInstr->block->blockIndex].vec8))
            return 0;

        for (instr = useInstr->block->firstPCode; instr; instr = instr->nextPCode) {
            if (instr == useInstr)
                break;

            op = instr->args;
            i = instr->argCount;
            while (i--) {
                if (
                    PC_OP_IS_WRITE_ANY_REGISTER(op, RegClass_GPR) &&
                    (op->data.reg.reg == reg2 || op->data.reg.reg == reg27)
                    )
                    return 0;
                op++;
            }
        }
    }

    if ((useInstr->flags & (fIsRead | fIsWrite | fPCodeFlag20000 | fPCodeFlag40000)) && object)
        useInstr->alias = make_alias(object, offset, nbytes_loaded_or_stored_by(useInstr));

    return 1;
}

static void propagateandremoveadd(int id) {
    PCode *instr;
    RegUseOrDef *list;
    Candidate *candidate;
    PCode *useInstr;

    candidate = Candidates + id;
    instr = candidate->pcode;

    if (instr->op == PC_ADDI && instr->args[2].kind == PCOp_MEMORY)
        instr->alias = make_alias(instr->args[2].data.mem.obj, instr->args[2].data.mem.offset, 1);

    for (list = candidate->list; list; list = list->next) {
        useInstr = Uses[list->id].pcode;

        if (instr->op == PC_ADD) {
            if (useInstr->flags & (fIsRead | fIsWrite)) {
                if (useInstr->args[2].kind != PCOp_REGISTER) {
                    useInstr->op += 2;
                    useInstr->flags |= fIsPtrOp;
                }
                useInstr->args[1] = instr->args[1];
                useInstr->args[2] = instr->args[2];
                useInstr->alias = instr->alias;
            } else if (useInstr->op == PC_ADDI) {
                CError_ASSERT(338, useInstr->args[2].data.imm.value == 0);
                change_opcode(useInstr, PC_ADD);
                useInstr->args[1] = instr->args[1];
                useInstr->args[2] = instr->args[2];
                useInstr->alias = instr->alias;
            } else if (useInstr->op == PC_MR) {
                change_opcode(useInstr, PC_ADD);
                useInstr->flags = instr->flags;
                change_num_operands(useInstr, 3);
                useInstr->args[1] = instr->args[1];
                useInstr->args[2] = instr->args[2];
                useInstr->alias = instr->alias;
            } else {
                CError_FATAL(352);
            }
        } else if (useInstr->op == PC_MR) {
            change_opcode(useInstr, PC_ADDI);
            useInstr->flags = instr->flags;
            useInstr->alias = instr->alias;
            change_num_operands(useInstr, 3);
            useInstr->args[1] = instr->args[1];
            useInstr->args[2] = instr->args[2];
        } else {
            useInstr->args[1] = instr->args[1];
            if (instr->args[2].kind == PCOp_IMMEDIATE) {
                SInt32 newValue = useInstr->args[2].data.imm.value + instr->args[2].data.imm.value;
                useInstr->args[2] = instr->args[2];
                useInstr->args[2].data.imm.value = newValue;
                useInstr->flags |= fIsPtrOp;
            } else if (instr->args[2].kind == PCOp_MEMORY) {
                SInt32 newValue = useInstr->args[2].data.imm.value + instr->args[2].data.mem.offset;
                useInstr->args[2] = instr->args[2];
                useInstr->args[2].data.mem.offset = newValue;
                useInstr->flags &= ~fIsPtrOp;
                if (useInstr->flags & (fIsRead | fIsWrite | fPCodeFlag20000 | fPCodeFlag40000))
                    useInstr->alias = make_alias(
                        useInstr->args[2].data.mem.obj,
                        useInstr->args[2].data.mem.offset,
                        nbytes_loaded_or_stored_by(useInstr));
            } else {
                CError_FATAL(382);
            }
        }
    }

    deletepcode(instr);
    propagatedadds = 1;
}

static Propagation add_prop = {
    &is_add,
    &addpropagatestouse,
    &propagateandremoveadd,
    "ADD",
    "ADDS",
    "a%ld",
    0
};

void propagateaddinstructions(Object *proc) {
    propagateinstructions(proc, &add_prop, (copts.optimizationlevel >= 4) ? 4 : 1, 1);
    propagatedadds = propagated_instructions;
}