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Strength-reduce 32 to 64 bit widening for XLOAD U8/U16 inputs.

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This commit is contained in:
Mike Pall 2011-02-06 00:45:39 +01:00
parent 26bb0fe24b
commit 4c74f70464
1 changed files with 3 additions and 0 deletions
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3
src/lj_opt_fold.c
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@ -917,6 +917,8 @@ LJFOLDF(simplify_conv_sext)
if (!(fins->op2 & IRCONV_SEXT)) if (!(fins->op2 & IRCONV_SEXT))
return NEXTFOLD; return NEXTFOLD;
PHIBARRIER(fleft); PHIBARRIER(fleft);
if (fleft->o == IR_XLOAD && (irt_isu8(fleft->t) || irt_isu16(fleft->t)))
goto ok_reduce;
if (fleft->o == IR_ADD && irref_isk(fleft->op2)) { if (fleft->o == IR_ADD && irref_isk(fleft->op2)) {
ofs = (int64_t)IR(fleft->op2)->i; ofs = (int64_t)IR(fleft->op2)->i;
ref = fleft->op1; ref = fleft->op1;
@ -926,6 +928,7 @@ LJFOLDF(simplify_conv_sext)
IRRef lo = J->scev.dir ? J->scev.start : J->scev.stop; IRRef lo = J->scev.dir ? J->scev.start : J->scev.stop;
lua_assert(irt_isint(J->scev.t)); lua_assert(irt_isint(J->scev.t));
if (lo && IR(lo)->i + ofs >= 0) { if (lo && IR(lo)->i + ofs >= 0) {
ok_reduce:
#if LJ_TARGET_X64 #if LJ_TARGET_X64
/* Eliminate widening. All 32 bit ops do an implicit zero-extension. */ /* Eliminate widening. All 32 bit ops do an implicit zero-extension. */
return LEFTFOLD; return LEFTFOLD;