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author | Richard Henderson <richard.henderson@linaro.org> | 2022-03-16 09:34:18 -0700 |
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committer | Richard Henderson <richard.henderson@linaro.org> | 2022-04-20 12:12:47 -0700 |
commit | c74824389e1a56781f947e23da68742e8faeaf77 (patch) | |
tree | 20821757f9162e18b2943a4e9872e8522090e276 /tcg/tcg.c | |
parent | 55d71e0b784e03dbd15bc13d75af88ed5340fde8 (diff) | |
download | qemu-c74824389e1a56781f947e23da68742e8faeaf77.zip qemu-c74824389e1a56781f947e23da68742e8faeaf77.tar.gz qemu-c74824389e1a56781f947e23da68742e8faeaf77.tar.bz2 |
tcg: Fix indirect lowering vs TCG_OPF_COND_BRANCH
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: b4cb76e6208 ("tcg: Do not kill globals at conditional branches")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'tcg/tcg.c')
-rw-r--r-- | tcg/tcg.c | 34 |
1 files changed, 27 insertions, 7 deletions
@@ -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: |