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tcg/optimize: Stop forcing z_mask to "garbage" for 32-bit values

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This "garbage" setting pre-dates the addition of the type
changing opcodes INDEX_op_ext_i32_i64, INDEX_op_extu_i32_i64,
and INDEX_op_extr{l,h}_i64_i32.

So now we have a definitive points at which to adjust z_mask
to eliminate such bits from the 32-bit operands.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2021-08-26 09:03:59 -07:00
parent 18cf3d07a2
commit faa2e10045
1 changed files with 16 additions and 19 deletions
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35
tcg/optimize.c
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@ -124,10 +124,6 @@ static void init_ts_info(OptContext *ctx, TCGTemp *ts)
ti->is_const = true;
ti->val = ts->val;
ti->z_mask = ts->val;
if (TCG_TARGET_REG_BITS > 32 && ts->type == TCG_TYPE_I32) {
/* High bits of a 32-bit quantity are garbage. */
ti->z_mask |= ~0xffffffffull;
}
} else {
ti->is_const = false;
ti->z_mask = -1;
@ -192,7 +188,6 @@ static bool tcg_opt_gen_mov(OptContext *ctx, TCGOp *op, TCGArg dst, TCGArg src)
TCGTemp *src_ts = arg_temp(src);
TempOptInfo *di;
TempOptInfo *si;
uint64_t z_mask;
TCGOpcode new_op;
if (ts_are_copies(dst_ts, src_ts)) {
@ -224,12 +219,7 @@ static bool tcg_opt_gen_mov(OptContext *ctx, TCGOp *op, TCGArg dst, TCGArg src)
op->args[0] = dst;
op->args[1] = src;
z_mask = si->z_mask;
if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_mov_i32) {
/* High bits of the destination are now garbage. */
z_mask |= ~0xffffffffull;
}
di->z_mask = z_mask;
di->z_mask = si->z_mask;
if (src_ts->type == dst_ts->type) {
TempOptInfo *ni = ts_info(si->next_copy);
@ -247,9 +237,14 @@ static bool tcg_opt_gen_mov(OptContext *ctx, TCGOp *op, TCGArg dst, TCGArg src)
static bool tcg_opt_gen_movi(OptContext *ctx, TCGOp *op,
TCGArg dst, uint64_t val)
{
/* Convert movi to mov with constant temp. */
TCGTemp *tv = tcg_constant_internal(ctx->type, val);
TCGTemp *tv;
if (ctx->type == TCG_TYPE_I32) {
val = (int32_t)val;
}
/* Convert movi to mov with constant temp. */
tv = tcg_constant_internal(ctx->type, val);
init_ts_info(ctx, tv);
return tcg_opt_gen_mov(ctx, op, dst, temp_arg(tv));
}
@ -721,14 +716,16 @@ static bool fold_masks(OptContext *ctx, TCGOp *op)
uint64_t z_mask = ctx->z_mask;
/*
* 32-bit ops generate 32-bit results. For the result is zero test
* below, we can ignore high bits, but for further optimizations we
* need to record that the high bits contain garbage.
* 32-bit ops generate 32-bit results, which for the purpose of
* simplifying tcg are sign-extended. Certainly that's how we
* represent our constants elsewhere. Note that the bits will
* be reset properly for a 64-bit value when encountering the
* type changing opcodes.
*/
if (ctx->type == TCG_TYPE_I32) {
ctx->z_mask |= MAKE_64BIT_MASK(32, 32);
a_mask &= MAKE_64BIT_MASK(0, 32);
z_mask &= MAKE_64BIT_MASK(0, 32);
a_mask = (int32_t)a_mask;
z_mask = (int32_t)z_mask;
ctx->z_mask = z_mask;
}
if (z_mask == 0) {