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tcg: Fix indirect lowering vs TCG_OPF_COND_BRANCH

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With TCG_OPF_COND_BRANCH, we extended the lifetimes of
globals across extended basic blocks.  This means that
the liveness computed in pass 1 does not kill globals
in the same way as normal temps.

Introduce TYPE_EBB to match this lifetime, so that we
get correct register allocation for the temps that we
introduce during the indirect lowering pass.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Fixes: b4cb76e620 ("tcg: Do not kill globals at conditional branches")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-03-16 09:34:18 -07:00
parent 55d71e0b78
commit c74824389e
2 changed files with 29 additions and 7 deletions
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2
include/tcg/tcg.h
View File

@ -433,6 +433,8 @@ typedef enum TCGTempVal {
typedef enum TCGTempKind {
/* Temp is dead at the end of all basic blocks. */
TEMP_NORMAL,
/* Temp is live across conditional branch, but dead otherwise. */
TEMP_EBB,
/* Temp is saved across basic blocks but dead at the end of TBs. */
TEMP_LOCAL,
/* Temp is saved across both basic blocks and translation blocks. */

34
tcg/tcg.c
View File

@ -1024,9 +1024,18 @@ void tcg_temp_free_internal(TCGTemp *ts)
TCGContext *s = tcg_ctx;
int k, idx;
/* In order to simplify users of tcg_constant_*, silently ignore free. */
if (ts->kind == TEMP_CONST) {
switch (ts->kind) {
case TEMP_CONST:
/*
* In order to simplify users of tcg_constant_*,
* silently ignore free.
*/
return;
case TEMP_NORMAL:
case TEMP_LOCAL:
break;
default:
g_assert_not_reached();
}
#if defined(CONFIG_DEBUG_TCG)
@ -1036,7 +1045,6 @@ void tcg_temp_free_internal(TCGTemp *ts)
}
#endif
tcg_debug_assert(ts->kind < TEMP_GLOBAL);
tcg_debug_assert(ts->temp_allocated != 0);
ts->temp_allocated = 0;
@ -1674,6 +1682,7 @@ static void tcg_reg_alloc_start(TCGContext *s)
case TEMP_GLOBAL:
break;
case TEMP_NORMAL:
case TEMP_EBB:
val = TEMP_VAL_DEAD;
/* fall through */
case TEMP_LOCAL:
@ -1701,6 +1710,9 @@ static char *tcg_get_arg_str_ptr(TCGContext *s, char *buf, int buf_size,
case TEMP_LOCAL:
snprintf(buf, buf_size, "loc%d", idx - s->nb_globals);
break;
case TEMP_EBB:
snprintf(buf, buf_size, "ebb%d", idx - s->nb_globals);
break;
case TEMP_NORMAL:
snprintf(buf, buf_size, "tmp%d", idx - s->nb_globals);
break;
@ -2378,6 +2390,7 @@ static void la_bb_end(TCGContext *s, int ng, int nt)
state = TS_DEAD | TS_MEM;
break;
case TEMP_NORMAL:
case TEMP_EBB:
case TEMP_CONST:
state = TS_DEAD;
break;
@ -2405,8 +2418,9 @@ static void la_global_sync(TCGContext *s, int ng)
}
/*
* liveness analysis: conditional branch: all temps are dead,
* globals and local temps should be synced.
* liveness analysis: conditional branch: all temps are dead unless
* explicitly live-across-conditional-branch, globals and local temps
* should be synced.
*/
static void la_bb_sync(TCGContext *s, int ng, int nt)
{
@ -2427,6 +2441,7 @@ static void la_bb_sync(TCGContext *s, int ng, int nt)
case TEMP_NORMAL:
s->temps[i].state = TS_DEAD;
break;
case TEMP_EBB:
case TEMP_CONST:
continue;
default:
@ -2797,6 +2812,7 @@ static bool liveness_pass_2(TCGContext *s)
TCGTemp *dts = tcg_temp_alloc(s);
dts->type = its->type;
dts->base_type = its->base_type;
dts->kind = TEMP_EBB;
its->state_ptr = dts;
} else {
its->state_ptr = NULL;
@ -3107,6 +3123,7 @@ static void temp_free_or_dead(TCGContext *s, TCGTemp *ts, int free_or_dead)
new_type = TEMP_VAL_MEM;
break;
case TEMP_NORMAL:
case TEMP_EBB:
new_type = free_or_dead < 0 ? TEMP_VAL_MEM : TEMP_VAL_DEAD;
break;
case TEMP_CONST:
@ -3353,6 +3370,7 @@ static void tcg_reg_alloc_bb_end(TCGContext *s, TCGRegSet allocated_regs)
temp_save(s, ts, allocated_regs);
break;
case TEMP_NORMAL:
case TEMP_EBB:
/* The liveness analysis already ensures that temps are dead.
Keep an tcg_debug_assert for safety. */
tcg_debug_assert(ts->val_type == TEMP_VAL_DEAD);
@ -3370,8 +3388,9 @@ static void tcg_reg_alloc_bb_end(TCGContext *s, TCGRegSet allocated_regs)
}
/*
* At a conditional branch, we assume all temporaries are dead and
* all globals and local temps are synced to their location.
* At a conditional branch, we assume all temporaries are dead unless
* explicitly live-across-conditional-branch; all globals and local
* temps are synced to their location.
*/
static void tcg_reg_alloc_cbranch(TCGContext *s, TCGRegSet allocated_regs)
{
@ -3390,6 +3409,7 @@ static void tcg_reg_alloc_cbranch(TCGContext *s, TCGRegSet allocated_regs)
case TEMP_NORMAL:
tcg_debug_assert(ts->val_type == TEMP_VAL_DEAD);
break;
case TEMP_EBB:
case TEMP_CONST:
break;
default: