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tcg/optimize: Lower TCG_COND_TST{EQ,NE} if unsupported
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After having performed other simplifications, lower any
remaining test comparisons with AND.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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@rth7680
rth7680 committed Feb 3, 2024
1 parent ceb9ee0 commit fb04ab7
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Showing 3 changed files with 55 additions and 9 deletions.
60 changes: 52 additions & 8 deletions tcg/optimize.c
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Original file line number Diff line number Diff line change
Expand Up @@ -364,6 +364,13 @@ static TCGArg arg_new_constant(OptContext *ctx, uint64_t val)
return temp_arg(ts);
}

static TCGArg arg_new_temp(OptContext *ctx)
{
TCGTemp *ts = tcg_temp_new_internal(ctx->type, TEMP_EBB);
init_ts_info(ctx, ts);
return temp_arg(ts);
}

static bool tcg_opt_gen_mov(OptContext *ctx, TCGOp *op, TCGArg dst, TCGArg src)
{
TCGTemp *dst_ts = arg_temp(dst);
Expand Down Expand Up @@ -782,7 +789,7 @@ static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
* Return -1 if the condition can't be simplified,
* and the result of the condition (0 or 1) if it can.
*/
static int do_constant_folding_cond1(OptContext *ctx, TCGArg dest,
static int do_constant_folding_cond1(OptContext *ctx, TCGOp *op, TCGArg dest,
TCGArg *p1, TCGArg *p2, TCGArg *pcond)
{
TCGCond cond;
Expand Down Expand Up @@ -818,11 +825,28 @@ static int do_constant_folding_cond1(OptContext *ctx, TCGArg dest,
? INT32_MIN : INT64_MIN))) {
*p2 = arg_new_constant(ctx, 0);
*pcond = tcg_tst_ltge_cond(cond);
return -1;
}

/* Expand to AND with a temporary if no backend support. */
if (!TCG_TARGET_HAS_tst) {
TCGOpcode and_opc = (ctx->type == TCG_TYPE_I32
? INDEX_op_and_i32 : INDEX_op_and_i64);
TCGOp *op2 = tcg_op_insert_before(ctx->tcg, op, and_opc, 3);
TCGArg tmp = arg_new_temp(ctx);

op2->args[0] = tmp;
op2->args[1] = *p1;
op2->args[2] = *p2;

*p1 = tmp;
*p2 = arg_new_constant(ctx, 0);
*pcond = tcg_tst_eqne_cond(cond);
}
return -1;
}

static int do_constant_folding_cond2(OptContext *ctx, TCGArg *args)
static int do_constant_folding_cond2(OptContext *ctx, TCGOp *op, TCGArg *args)
{
TCGArg al, ah, bl, bh;
TCGCond c;
Expand Down Expand Up @@ -898,6 +922,26 @@ static int do_constant_folding_cond2(OptContext *ctx, TCGArg *args)
return -1;
}
}

/* Expand to AND with a temporary if no backend support. */
if (!TCG_TARGET_HAS_tst && is_tst_cond(c)) {
TCGOp *op1 = tcg_op_insert_before(ctx->tcg, op, INDEX_op_and_i32, 3);
TCGOp *op2 = tcg_op_insert_before(ctx->tcg, op, INDEX_op_and_i32, 3);
TCGArg t1 = arg_new_temp(ctx);
TCGArg t2 = arg_new_temp(ctx);

op1->args[0] = t1;
op1->args[1] = al;
op1->args[2] = bl;
op2->args[0] = t2;
op2->args[1] = ah;
op2->args[2] = bh;

args[0] = t1;
args[1] = t2;
args[3] = args[2] = arg_new_constant(ctx, 0);
args[4] = tcg_tst_eqne_cond(c);
}
return -1;
}

Expand Down Expand Up @@ -1298,7 +1342,7 @@ static bool fold_andc(OptContext *ctx, TCGOp *op)

static bool fold_brcond(OptContext *ctx, TCGOp *op)
{
int i = do_constant_folding_cond1(ctx, NO_DEST, &op->args[0],
int i = do_constant_folding_cond1(ctx, op, NO_DEST, &op->args[0],
&op->args[1], &op->args[2]);
if (i == 0) {
tcg_op_remove(ctx->tcg, op);
Expand All @@ -1317,7 +1361,7 @@ static bool fold_brcond2(OptContext *ctx, TCGOp *op)
TCGArg label;
int i, inv = 0;

i = do_constant_folding_cond2(ctx, &op->args[0]);
i = do_constant_folding_cond2(ctx, op, &op->args[0]);
cond = op->args[4];
label = op->args[5];
if (i >= 0) {
Expand Down Expand Up @@ -1815,7 +1859,7 @@ static bool fold_movcond(OptContext *ctx, TCGOp *op)
op->args[5] = tcg_invert_cond(op->args[5]);
}

i = do_constant_folding_cond1(ctx, NO_DEST, &op->args[1],
i = do_constant_folding_cond1(ctx, op, NO_DEST, &op->args[1],
&op->args[2], &op->args[5]);
if (i >= 0) {
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[4 - i]);
Expand Down Expand Up @@ -2151,7 +2195,7 @@ static void fold_setcond_tst_pow2(OptContext *ctx, TCGOp *op, bool neg)

static bool fold_setcond(OptContext *ctx, TCGOp *op)
{
int i = do_constant_folding_cond1(ctx, op->args[0], &op->args[1],
int i = do_constant_folding_cond1(ctx, op, op->args[0], &op->args[1],
&op->args[2], &op->args[3]);
if (i >= 0) {
return tcg_opt_gen_movi(ctx, op, op->args[0], i);
Expand All @@ -2165,7 +2209,7 @@ static bool fold_setcond(OptContext *ctx, TCGOp *op)

static bool fold_negsetcond(OptContext *ctx, TCGOp *op)
{
int i = do_constant_folding_cond1(ctx, op->args[0], &op->args[1],
int i = do_constant_folding_cond1(ctx, op, op->args[0], &op->args[1],
&op->args[2], &op->args[3]);
if (i >= 0) {
return tcg_opt_gen_movi(ctx, op, op->args[0], -i);
Expand All @@ -2182,7 +2226,7 @@ static bool fold_setcond2(OptContext *ctx, TCGOp *op)
TCGCond cond;
int i, inv = 0;

i = do_constant_folding_cond2(ctx, &op->args[1]);
i = do_constant_folding_cond2(ctx, op, &op->args[1]);
cond = op->args[5];
if (i >= 0) {
goto do_setcond_const;
Expand Down
2 changes: 2 additions & 0 deletions tcg/tcg-internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,8 @@ static inline TCGv_i64 TCGV128_HIGH(TCGv_i128 t)

bool tcg_target_has_memory_bswap(MemOp memop);

TCGTemp *tcg_temp_new_internal(TCGType type, TCGTempKind kind);

/*
* Locate or create a read-only temporary that is a constant.
* This kind of temporary need not be freed, but for convenience
Expand Down
2 changes: 1 addition & 1 deletion tcg/tcg.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1655,7 +1655,7 @@ TCGv_ptr tcg_global_mem_new_ptr(TCGv_ptr reg, intptr_t off, const char *name)
return temp_tcgv_ptr(ts);
}

static TCGTemp *tcg_temp_new_internal(TCGType type, TCGTempKind kind)
TCGTemp *tcg_temp_new_internal(TCGType type, TCGTempKind kind)
{
TCGContext *s = tcg_ctx;
TCGTemp *ts;
Expand Down

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