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Add conversions for type mismatches in XSTORE forwarding.

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Mike Pall 2010-12-31 22:50:06 +01:00
parent 3b47eba9cc
commit ddfa7fc246
1 changed files with 21 additions and 7 deletions
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28
src/lj_opt_mem.c
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@ -567,7 +567,7 @@ static AliasRet aa_xref(jit_State *J, IRIns *refa, IRIns *xa, IRIns *xb)
if (irt_sametype(xa->t, xb->t)) {
if (refa == refb)
return ALIAS_MUST; /* Shortcut for same refs with identical type. */
} else if (!(irt_typerange(xa->t, IRT_I8, IRT_INT) &&
} else if (!(irt_typerange(xa->t, IRT_I8, IRT_U64) &&
((xa->t.irt - IRT_I8) ^ (xb->t.irt - IRT_I8)) == 1)) {
return ALIAS_NO;
}
@ -592,11 +592,7 @@ static AliasRet aa_xref(jit_State *J, IRIns *refa, IRIns *xa, IRIns *xb)
/* This assumes strictly-typed, non-overlapping accesses. */
if (ofsa != ofsb)
return ALIAS_NO; /* base+-o1 vs. base+-o2 and o1 != o2. */
/* Unsigned vs. signed access to the same address.
** Really ALIAS_MUST, but store forwarding would lose the type.
** This is rare, so return ALIAS_MAY for now.
*/
return ALIAS_MAY;
return ALIAS_MUST; /* Unsigned vs. signed access to the same address. */
}
/* NYI: structural disambiguation. */
return aa_cnew(J, basea, baseb); /* Try to disambiguate allocations. */
@ -682,7 +678,25 @@ retry:
switch (aa_xref(J, xr, fins, store)) {
case ALIAS_NO: break; /* Continue searching. */
case ALIAS_MAY: lim = ref; goto cselim; /* Limit search for load. */
case ALIAS_MUST: return store->op2; /* Store forwarding. */
case ALIAS_MUST:
/* Emit conversion if the loaded type doesn't match the forwarded type. */
if (!irt_sametype(fins->t, IR(store->op2)->t)) {
IRType st = irt_type(fins->t);
if (st == IRT_I8 || st == IRT_I16) { /* Trunc + sign-extend. */
st |= IRCONV_SEXT;
} else if (st == IRT_U8 || st == IRT_U16) { /* Trunc + zero-extend. */
} else if (st == IRT_INT && irt_isu32(IR(store->op2)->t)) {
st = IRT_U32; /* Needs dummy CONV.int.u32. */
} else { /* I64/U64 are boxed, U32 is hidden behind a CONV.num.u32. */
goto store_fwd;
}
fins->ot = IRTI(IR_CONV);
fins->op1 = store->op2;
fins->op2 = (IRT_INT<<5)|st;
return RETRYFOLD;
}
store_fwd:
return store->op2; /* Store forwarding. */
}
ref = store->prev;
}