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Avoid fusing loads if there are multiple references.

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This commit is contained in:
Mike Pall 2010-12-08 03:26:53 +01:00
parent 72744dabd9
commit 3c78a7f468
1 changed files with 13 additions and 8 deletions
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21
src/lj_asm.c
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@ -1144,16 +1144,21 @@ static int asm_isk32(ASMState *as, IRRef ref, int32_t *k)
return 0; return 0;
} }
/* Check if there's no conflicting instruction between curins and ref. */ /* Check if there's no conflicting instruction between curins and ref.
static int noconflict(ASMState *as, IRRef ref, IROp conflict) ** Also avoid fusing loads if there are multiple references.
*/
static int noconflict(ASMState *as, IRRef ref, IROp conflict, int noload)
{ {
IRIns *ir = as->ir; IRIns *ir = as->ir;
IRRef i = as->curins; IRRef i = as->curins;
if (i > ref + CONFLICT_SEARCH_LIM) if (i > ref + CONFLICT_SEARCH_LIM)
return 0; /* Give up, ref is too far away. */ return 0; /* Give up, ref is too far away. */
while (--i > ref) while (--i > ref) {
if (ir[i].o == conflict) if (ir[i].o == conflict)
return 0; /* Conflict found. */ return 0; /* Conflict found. */
else if (!noload && (ir[i].op1 == ref || ir[i].op2 == ref))
return 0;
}
return 1; /* Ok, no conflict. */ return 1; /* Ok, no conflict. */
} }
@ -1167,7 +1172,7 @@ static IRRef asm_fuseabase(ASMState *as, IRRef ref)
lua_assert(irb->op2 == IRFL_TAB_ARRAY); lua_assert(irb->op2 == IRFL_TAB_ARRAY);
/* We can avoid the FLOAD of t->array for colocated arrays. */ /* We can avoid the FLOAD of t->array for colocated arrays. */
if (ira->o == IR_TNEW && ira->op1 <= LJ_MAX_COLOSIZE && if (ira->o == IR_TNEW && ira->op1 <= LJ_MAX_COLOSIZE &&
noconflict(as, irb->op1, IR_NEWREF)) { noconflict(as, irb->op1, IR_NEWREF, 1)) {
as->mrm.ofs = (int32_t)sizeof(GCtab); /* Ofs to colocated array. */ as->mrm.ofs = (int32_t)sizeof(GCtab); /* Ofs to colocated array. */
return irb->op1; /* Table obj. */ return irb->op1; /* Table obj. */
} }
@ -1377,7 +1382,7 @@ static Reg asm_fuseload(ASMState *as, IRRef ref, RegSet allow)
RegSet xallow = (allow & RSET_GPR) ? allow : RSET_GPR; RegSet xallow = (allow & RSET_GPR) ? allow : RSET_GPR;
if (ir->o == IR_SLOAD) { if (ir->o == IR_SLOAD) {
if (!(ir->op2 & (IRSLOAD_PARENT|IRSLOAD_CONVERT)) && if (!(ir->op2 & (IRSLOAD_PARENT|IRSLOAD_CONVERT)) &&
noconflict(as, ref, IR_RETF)) { noconflict(as, ref, IR_RETF, 0)) {
as->mrm.base = (uint8_t)ra_alloc1(as, REF_BASE, xallow); as->mrm.base = (uint8_t)ra_alloc1(as, REF_BASE, xallow);
as->mrm.ofs = 8*((int32_t)ir->op1-1) + ((ir->op2&IRSLOAD_FRAME)?4:0); as->mrm.ofs = 8*((int32_t)ir->op1-1) + ((ir->op2&IRSLOAD_FRAME)?4:0);
as->mrm.idx = RID_NONE; as->mrm.idx = RID_NONE;
@ -1386,12 +1391,12 @@ static Reg asm_fuseload(ASMState *as, IRRef ref, RegSet allow)
} else if (ir->o == IR_FLOAD) { } else if (ir->o == IR_FLOAD) {
/* Generic fusion is only ok for 32 bit operand (but see asm_comp). */ /* Generic fusion is only ok for 32 bit operand (but see asm_comp). */
if ((irt_isint(ir->t) || irt_isaddr(ir->t)) && if ((irt_isint(ir->t) || irt_isaddr(ir->t)) &&
noconflict(as, ref, IR_FSTORE)) { noconflict(as, ref, IR_FSTORE, 0)) {
asm_fusefref(as, ir, xallow); asm_fusefref(as, ir, xallow);
return RID_MRM; return RID_MRM;
} }
} else if (ir->o == IR_ALOAD || ir->o == IR_HLOAD || ir->o == IR_ULOAD) { } else if (ir->o == IR_ALOAD || ir->o == IR_HLOAD || ir->o == IR_ULOAD) {
if (noconflict(as, ref, ir->o + IRDELTA_L2S)) { if (noconflict(as, ref, ir->o + IRDELTA_L2S, 0)) {
asm_fuseahuref(as, ir->op1, xallow); asm_fuseahuref(as, ir->op1, xallow);
return RID_MRM; return RID_MRM;
} }
@ -1400,7 +1405,7 @@ static Reg asm_fuseload(ASMState *as, IRRef ref, RegSet allow)
** Fusing unaligned memory operands is ok on x86 (except for SIMD types). ** Fusing unaligned memory operands is ok on x86 (except for SIMD types).
*/ */
if ((!irt_typerange(ir->t, IRT_I8, IRT_U16)) && if ((!irt_typerange(ir->t, IRT_I8, IRT_U16)) &&
noconflict(as, ref, IR_XSTORE)) { noconflict(as, ref, IR_XSTORE, 0)) {
asm_fusexref(as, ir->op1, xallow); asm_fusexref(as, ir->op1, xallow);
return RID_MRM; return RID_MRM;
} }