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Avoid fusing potentially negative indexes into AREF on x64.

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Mike Pall 2010-09-18 18:34:38 +02:00
parent 9203d278d0
commit 52b922c1e9
1 changed files with 3 additions and 2 deletions
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5
src/lj_asm.c
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@ -1148,7 +1148,8 @@ static void asm_fusearef(ASMState *as, IRIns *ir, RegSet allow)
/* Fuse a constant ADD (e.g. t[i+1]) into the offset. /* Fuse a constant ADD (e.g. t[i+1]) into the offset.
** Doesn't help much without ABCelim, but reduces register pressure. ** Doesn't help much without ABCelim, but reduces register pressure.
*/ */
if (mayfuse(as, ir->op2) && ra_noreg(irx->r) && if (!LJ_64 && /* Has bad effects with negative index on x64. */
mayfuse(as, ir->op2) && ra_noreg(irx->r) &&
irx->o == IR_ADD && irref_isk(irx->op2)) { irx->o == IR_ADD && irref_isk(irx->op2)) {
as->mrm.ofs += 8*IR(irx->op2)->i; as->mrm.ofs += 8*IR(irx->op2)->i;
as->mrm.idx = (uint8_t)ra_alloc1(as, irx->op1, allow); as->mrm.idx = (uint8_t)ra_alloc1(as, irx->op1, allow);
@ -1236,7 +1237,7 @@ static void asm_fusestrref(ASMState *as, IRIns *ir, RegSet allow)
} else { } else {
Reg r; Reg r;
/* Fuse a constant add into the offset, e.g. string.sub(s, i+10). */ /* Fuse a constant add into the offset, e.g. string.sub(s, i+10). */
if (!LJ_64 && /* NYI: has bad effects with negative index on x64. */ if (!LJ_64 && /* Has bad effects with negative index on x64. */
mayfuse(as, ir->op2) && irr->o == IR_ADD && irref_isk(irr->op2)) { mayfuse(as, ir->op2) && irr->o == IR_ADD && irref_isk(irr->op2)) {
as->mrm.ofs += IR(irr->op2)->i; as->mrm.ofs += IR(irr->op2)->i;
r = ra_alloc1(as, irr->op1, allow); r = ra_alloc1(as, irr->op1, allow);