@@ -174,6 +174,7 @@ typedef struct DisasContext {
target_ulong jump_pc[2];
int mem_idx;
+ bool cpu_cond_live;
bool fpu_enabled;
bool address_mask_32bit;
#ifndef CONFIG_USER_ONLY
@@ -850,6 +851,19 @@ static void gen_op_eval_fbo(TCGv dst, TCGv src, unsigned int fcc_offset)
tcg_gen_xori_tl(dst, dst, 0x1);
}
+static void finishing_insn(DisasContext *dc)
+{
+ /*
+ * From here, there is no future path through an unwinding exception.
+ * If the current insn cannot raise an exception, the computation of
+ * cpu_cond may be able to be elided.
+ */
+ if (dc->cpu_cond_live) {
+ tcg_gen_discard_tl(cpu_cond);
+ dc->cpu_cond_live = false;
+ }
+}
+
static void gen_generic_branch(DisasContext *dc)
{
TCGv npc0 = tcg_constant_tl(dc->jump_pc[0]);
@@ -896,6 +910,7 @@ static void save_state(DisasContext *dc)
static void gen_exception(DisasContext *dc, int which)
{
+ finishing_insn(dc);
save_state(dc);
gen_helper_raise_exception(tcg_env, tcg_constant_i32(which));
dc->base.is_jmp = DISAS_NORETURN;
@@ -937,6 +952,8 @@ static void gen_check_align(DisasContext *dc, TCGv addr, int mask)
static void gen_mov_pc_npc(DisasContext *dc)
{
+ finishing_insn(dc);
+
if (dc->npc & 3) {
switch (dc->npc) {
case JUMP_PC:
@@ -2247,6 +2264,8 @@ static bool advance_pc(DisasContext *dc)
{
TCGLabel *l1;
+ finishing_insn(dc);
+
if (dc->npc & 3) {
switch (dc->npc) {
case DYNAMIC_PC:
@@ -2290,6 +2309,8 @@ static bool advance_jump_cond(DisasContext *dc, DisasCompare *cmp,
{
target_ulong npc = dc->npc;
+ finishing_insn(dc);
+
if (cmp->cond == TCG_COND_ALWAYS) {
if (annul) {
dc->pc = dest;
@@ -2354,6 +2375,7 @@ static bool advance_jump_cond(DisasContext *dc, DisasCompare *cmp,
} else {
tcg_gen_setcondi_tl(cmp->cond, cpu_cond, cmp->c1, cmp->c2);
}
+ dc->cpu_cond_live = true;
}
}
return true;
@@ -2520,6 +2542,8 @@ static bool trans_Tcc(DisasContext *dc, arg_Tcc *a)
tcg_gen_addi_i32(trap, trap, TT_TRAP);
}
+ finishing_insn(dc);
+
/* Trap always. */
if (a->cond == 8) {
save_state(dc);
@@ -3198,6 +3222,7 @@ TRANS(WRSTICK_CMPR, 64, do_wr_special, a, supervisor(dc), do_wrstick_cmpr)
static void do_wrpowerdown(DisasContext *dc, TCGv src)
{
+ finishing_insn(dc);
save_state(dc);
gen_helper_power_down(tcg_env);
}
@@ -5148,6 +5173,8 @@ static void sparc_tr_tb_stop(DisasContextBase *dcbase, CPUState *cs)
DisasDelayException *e, *e_next;
bool may_lookup;
+ finishing_insn(dc);
+
switch (dc->base.is_jmp) {
case DISAS_NEXT:
case DISAS_TOO_MANY:
If the insn raises no exceptions, there will be no path in which cpu_cond is used, and so the computation may be optimized away. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- target/sparc/translate.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)