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tcg/optimize: further optimize brcond/movcond/setcond 

When both argument of brcond/movcond/setcond are the same or when one
of the two values is a constant equal to zero, it's possible to do
further optimizations.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Aurelien Jarno 2012-09-18 19:37:00 +02:00
parent 3c94193e0b
commit b336ceb691
1 changed files with 80 additions and 55 deletions
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135
tcg/optimize.c
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@ -292,58 +292,88 @@ static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y)
return res;
}
/* Return 2 if the condition can't be simplified, and the result
of the condition (0 or 1) if it can */
static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x,
TCGArg y, TCGCond c)
{
switch (op_bits(op)) {
case 32:
switch (c) {
case TCG_COND_EQ:
return (uint32_t)x == (uint32_t)y;
case TCG_COND_NE:
return (uint32_t)x != (uint32_t)y;
case TCG_COND_LT:
return (int32_t)x < (int32_t)y;
case TCG_COND_GE:
return (int32_t)x >= (int32_t)y;
case TCG_COND_LE:
return (int32_t)x <= (int32_t)y;
case TCG_COND_GT:
return (int32_t)x > (int32_t)y;
case TCG_COND_LTU:
return (uint32_t)x < (uint32_t)y;
case TCG_COND_GEU:
return (uint32_t)x >= (uint32_t)y;
case TCG_COND_LEU:
return (uint32_t)x <= (uint32_t)y;
case TCG_COND_GTU:
return (uint32_t)x > (uint32_t)y;
if (temps[x].state == TCG_TEMP_CONST && temps[y].state == TCG_TEMP_CONST) {
switch (op_bits(op)) {
case 32:
switch (c) {
case TCG_COND_EQ:
return (uint32_t)temps[x].val == (uint32_t)temps[y].val;
case TCG_COND_NE:
return (uint32_t)temps[x].val != (uint32_t)temps[y].val;
case TCG_COND_LT:
return (int32_t)temps[x].val < (int32_t)temps[y].val;
case TCG_COND_GE:
return (int32_t)temps[x].val >= (int32_t)temps[y].val;
case TCG_COND_LE:
return (int32_t)temps[x].val <= (int32_t)temps[y].val;
case TCG_COND_GT:
return (int32_t)temps[x].val > (int32_t)temps[y].val;
case TCG_COND_LTU:
return (uint32_t)temps[x].val < (uint32_t)temps[y].val;
case TCG_COND_GEU:
return (uint32_t)temps[x].val >= (uint32_t)temps[y].val;
case TCG_COND_LEU:
return (uint32_t)temps[x].val <= (uint32_t)temps[y].val;
case TCG_COND_GTU:
return (uint32_t)temps[x].val > (uint32_t)temps[y].val;
}
break;
case 64:
switch (c) {
case TCG_COND_EQ:
return (uint64_t)temps[x].val == (uint64_t)temps[y].val;
case TCG_COND_NE:
return (uint64_t)temps[x].val != (uint64_t)temps[y].val;
case TCG_COND_LT:
return (int64_t)temps[x].val < (int64_t)temps[y].val;
case TCG_COND_GE:
return (int64_t)temps[x].val >= (int64_t)temps[y].val;
case TCG_COND_LE:
return (int64_t)temps[x].val <= (int64_t)temps[y].val;
case TCG_COND_GT:
return (int64_t)temps[x].val > (int64_t)temps[y].val;
case TCG_COND_LTU:
return (uint64_t)temps[x].val < (uint64_t)temps[y].val;
case TCG_COND_GEU:
return (uint64_t)temps[x].val >= (uint64_t)temps[y].val;
case TCG_COND_LEU:
return (uint64_t)temps[x].val <= (uint64_t)temps[y].val;
case TCG_COND_GTU:
return (uint64_t)temps[x].val > (uint64_t)temps[y].val;
}
break;
}
break;
case 64:
} else if (temps_are_copies(x, y)) {
switch (c) {
case TCG_COND_EQ:
return (uint64_t)x == (uint64_t)y;
case TCG_COND_NE:
return (uint64_t)x != (uint64_t)y;
case TCG_COND_LT:
return (int64_t)x < (int64_t)y;
case TCG_COND_GE:
return (int64_t)x >= (int64_t)y;
case TCG_COND_LE:
return (int64_t)x <= (int64_t)y;
case TCG_COND_GT:
return (int64_t)x > (int64_t)y;
case TCG_COND_LTU:
return (uint64_t)x < (uint64_t)y;
case TCG_COND_GEU:
return (uint64_t)x >= (uint64_t)y;
case TCG_COND_LEU:
return (uint64_t)x <= (uint64_t)y;
case TCG_COND_LT:
case TCG_COND_GTU:
return (uint64_t)x > (uint64_t)y;
case TCG_COND_NE:
return 0;
case TCG_COND_GE:
case TCG_COND_GEU:
case TCG_COND_LE:
case TCG_COND_LEU:
case TCG_COND_EQ:
return 1;
}
break;
} else if (temps[y].state == TCG_TEMP_CONST && temps[y].val == 0) {
switch (c) {
case TCG_COND_LTU:
return 0;
case TCG_COND_GEU:
return 1;
default:
return 2;
}
} else {
return 2;
}
fprintf(stderr,
@ -636,11 +666,9 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
args += 3;
break;
CASE_OP_32_64(setcond):
if (temps[args[1]].state == TCG_TEMP_CONST
&& temps[args[2]].state == TCG_TEMP_CONST) {
tmp = do_constant_folding_cond(op, args[1], args[2], args[3]);
if (tmp != 2) {
gen_opc_buf[op_index] = op_to_movi(op);
tmp = do_constant_folding_cond(op, temps[args[1]].val,
temps[args[2]].val, args[3]);
tcg_opt_gen_movi(gen_args, args[0], tmp);
gen_args += 2;
} else {
@ -654,10 +682,9 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
args += 4;
break;
CASE_OP_32_64(brcond):
if (temps[args[0]].state == TCG_TEMP_CONST
&& temps[args[1]].state == TCG_TEMP_CONST) {
if (do_constant_folding_cond(op, temps[args[0]].val,
temps[args[1]].val, args[2])) {
tmp = do_constant_folding_cond(op, args[0], args[1], args[2]);
if (tmp != 2) {
if (tmp) {
memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
gen_opc_buf[op_index] = INDEX_op_br;
gen_args[0] = args[3];
@ -677,10 +704,8 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
args += 4;
break;
CASE_OP_32_64(movcond):
if (temps[args[1]].state == TCG_TEMP_CONST
&& temps[args[2]].state == TCG_TEMP_CONST) {
tmp = do_constant_folding_cond(op, temps[args[1]].val,
temps[args[2]].val, args[5]);
tmp = do_constant_folding_cond(op, args[1], args[2], args[5]);
if (tmp != 2) {
if (temps_are_copies(args[0], args[4-tmp])) {
gen_opc_buf[op_index] = INDEX_op_nop;
} else if (temps[args[4-tmp]].state == TCG_TEMP_CONST) {