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FFI: Turn cdata indexing into x86/x64 [base+idx*sz+ofs] addressing.

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This commit is contained in:
Mike Pall 2010-12-08 02:36:09 +01:00
parent d778680098
commit 3ef6a53cfa
1 changed files with 36 additions and 4 deletions
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40
src/lj_asm.c
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@ -1307,12 +1307,44 @@ static void asm_fusexref(ASMState *as, IRRef ref, RegSet allow)
as->mrm.base = RID_NONE;
} else if (ir->o == IR_STRREF) {
asm_fusestrref(as, ir, allow);
} else if (mayfuse(as, ref) && ir->o == IR_ADD &&
asm_isk32(as, ir->op2, &as->mrm.ofs)) {
/* NYI: gather index and shifts. */
as->mrm.base = (uint8_t)ra_alloc1(as, ir->op1, allow);
} else {
as->mrm.ofs = 0;
if (mayfuse(as, ref) && ir->o == IR_ADD && ra_noreg(ir->r)) {
/* Gather (base+idx*sz)+ofs as emitted by cdata ptr/array indexing. */
IRIns *irx;
IRRef idx;
Reg r;
if (asm_isk32(as, ir->op2, &as->mrm.ofs)) { /* Recognize x+ofs. */
ref = ir->op1;
ir = IR(ref);
if (!(ir->o == IR_ADD && mayfuse(as, ref) && ra_noreg(ir->r)))
goto noadd;
}
as->mrm.scale = XM_SCALE1;
idx = ir->op1;
ref = ir->op2;
irx = IR(idx);
if (!(irx->o == IR_BSHL || irx->o == IR_ADD)) { /* Try other operand. */
idx = ir->op2;
ref = ir->op1;
irx = IR(idx);
}
if (mayfuse(as, idx) && ra_noreg(irx->r)) {
if (irx->o == IR_BSHL && irref_isk(irx->op2) && IR(irx->op2)->i <= 3) {
/* Recognize idx<<b with b = 0-3, corresponding to sz = (1),2,4,8. */
idx = irx->op1;
as->mrm.scale = (uint8_t)(IR(irx->op2)->i << 6);
} else if (irx->o == IR_ADD && irx->op1 == irx->op2) {
/* FOLD does idx*2 ==> idx<<1 ==> idx+idx. */
idx = irx->op1;
as->mrm.scale = XM_SCALE2;
}
}
r = ra_alloc1(as, idx, allow);
rset_clear(allow, r);
as->mrm.idx = (uint8_t)r;
}
noadd:
as->mrm.base = (uint8_t)ra_alloc1(as, ref, allow);
}
}