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x64/LJ_GC64: Avoid store-to-load forwarding stall after stack restore.

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Thanks to Sergey Kaplun. #1485
This commit is contained in:
Mike Pall 2026-07-18 09:48:48 +02:00
parent 3c4f9fe205
commit 14d8a7a27d
1 changed files with 7 additions and 4 deletions
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11
src/lj_asm_x86.h
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@ -1112,10 +1112,12 @@ static void asm_tvptr(ASMState *as, Reg dest, IRRef ref, MSize mode)
} else { } else {
#if LJ_GC64 #if LJ_GC64
if (irref_isk(ref)) { if (irref_isk(ref)) {
Reg tmp;
TValue k; TValue k;
lj_ir_kvalue(as->J->L, &k, ir); lj_ir_kvalue(as->J->L, &k, ir);
emit_movmroi(as, dest, 4, k.u32.hi); tmp = ra_scratch(as, rset_exclude(RSET_GPR, dest));
emit_movmroi(as, dest, 0, k.u32.lo); emit_rmro(as, XO_MOVto, tmp|REX_64, dest, 0);
emit_loadu64(as, tmp, k.u64);
} else { } else {
/* TODO: 64 bit store + 32 bit load-modify-store is suboptimal. */ /* TODO: 64 bit store + 32 bit load-modify-store is suboptimal. */
Reg src = ra_alloc1(as, ref, rset_exclude(RSET_GPR, dest)); Reg src = ra_alloc1(as, ref, rset_exclude(RSET_GPR, dest));
@ -2787,8 +2789,9 @@ static void asm_stack_restore(ASMState *as, SnapShot *snap)
emit_i32(as, -1); emit_i32(as, -1);
emit_rmro(as, XO_MOVmi, REX_64, RID_BASE, ofs); emit_rmro(as, XO_MOVmi, REX_64, RID_BASE, ofs);
} else { } else {
emit_movmroi(as, RID_BASE, ofs+4, k.u32.hi); Reg tmp = ra_scratch(as, rset_exclude(RSET_GPR, RID_BASE));
emit_movmroi(as, RID_BASE, ofs, k.u32.lo); emit_rmro(as, XO_MOVto, tmp|REX_64, RID_BASE, ofs);
emit_loadu64(as, tmp, k.u64);
} }
#else #else
} else if (!irt_ispri(ir->t)) { } else if (!irt_ispri(ir->t)) {