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target-mips: optimize ddiv/ddivu/div/divu with movcond 

The result of a division by 0, or a division of INT_MIN by -1 in the
signed case, is unpredictable. Just replace 0 by 1 in that case so that
it doesn't trigger a floating point exception on the host.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Aurelien Jarno 2012-10-09 21:53:21 +02:00
parent acf1246558
commit 51127181cf
1 changed files with 37 additions and 48 deletions
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85
target-mips/translate.c
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@ -2653,60 +2653,48 @@ static void gen_muldiv (DisasContext *ctx, uint32_t opc,
TCGv t0, t1;
unsigned int acc;
switch (opc) {
case OPC_DIV:
case OPC_DIVU:
#if defined(TARGET_MIPS64)
case OPC_DDIV:
case OPC_DDIVU:
#endif
t0 = tcg_temp_local_new();
t1 = tcg_temp_local_new();
break;
default:
t0 = tcg_temp_new();
t1 = tcg_temp_new();
break;
}
t0 = tcg_temp_new();
t1 = tcg_temp_new();
gen_load_gpr(t0, rs);
gen_load_gpr(t1, rt);
switch (opc) {
case OPC_DIV:
{
int l1 = gen_new_label();
int l2 = gen_new_label();
TCGv t2 = tcg_temp_new();
TCGv t3 = tcg_temp_new();
tcg_gen_ext32s_tl(t0, t0);
tcg_gen_ext32s_tl(t1, t1);
tcg_gen_brcondi_tl(TCG_COND_EQ, t1, 0, l1);
tcg_gen_brcondi_tl(TCG_COND_NE, t0, INT_MIN, l2);
tcg_gen_brcondi_tl(TCG_COND_NE, t1, -1, l2);
tcg_gen_mov_tl(cpu_LO[0], t0);
tcg_gen_movi_tl(cpu_HI[0], 0);
tcg_gen_br(l1);
gen_set_label(l2);
tcg_gen_setcondi_tl(TCG_COND_EQ, t2, t0, INT_MIN);
tcg_gen_setcondi_tl(TCG_COND_EQ, t3, t1, -1);
tcg_gen_and_tl(t2, t2, t3);
tcg_gen_setcondi_tl(TCG_COND_EQ, t3, t1, 0);
tcg_gen_or_tl(t2, t2, t3);
tcg_gen_movi_tl(t3, 0);
tcg_gen_movcond_tl(TCG_COND_NE, t1, t2, t3, t2, t1);
tcg_gen_div_tl(cpu_LO[0], t0, t1);
tcg_gen_rem_tl(cpu_HI[0], t0, t1);
tcg_gen_ext32s_tl(cpu_LO[0], cpu_LO[0]);
tcg_gen_ext32s_tl(cpu_HI[0], cpu_HI[0]);
gen_set_label(l1);
tcg_temp_free(t3);
tcg_temp_free(t2);
}
opn = "div";
break;
case OPC_DIVU:
{
int l1 = gen_new_label();
TCGv t2 = tcg_const_tl(0);
TCGv t3 = tcg_const_tl(1);
tcg_gen_ext32u_tl(t0, t0);
tcg_gen_ext32u_tl(t1, t1);
tcg_gen_brcondi_tl(TCG_COND_EQ, t1, 0, l1);
tcg_gen_movcond_tl(TCG_COND_EQ, t1, t1, t2, t3, t1);
tcg_gen_divu_tl(cpu_LO[0], t0, t1);
tcg_gen_remu_tl(cpu_HI[0], t0, t1);
tcg_gen_ext32s_tl(cpu_LO[0], cpu_LO[0]);
tcg_gen_ext32s_tl(cpu_HI[0], cpu_HI[0]);
gen_set_label(l1);
tcg_temp_free(t3);
tcg_temp_free(t2);
}
opn = "divu";
break;
@ -2759,30 +2747,31 @@ static void gen_muldiv (DisasContext *ctx, uint32_t opc,
#if defined(TARGET_MIPS64)
case OPC_DDIV:
{
int l1 = gen_new_label();
int l2 = gen_new_label();
tcg_gen_brcondi_tl(TCG_COND_EQ, t1, 0, l1);
tcg_gen_brcondi_tl(TCG_COND_NE, t0, -1LL << 63, l2);
tcg_gen_brcondi_tl(TCG_COND_NE, t1, -1LL, l2);
tcg_gen_mov_tl(cpu_LO[0], t0);
tcg_gen_movi_tl(cpu_HI[0], 0);
tcg_gen_br(l1);
gen_set_label(l2);
tcg_gen_div_i64(cpu_LO[0], t0, t1);
tcg_gen_rem_i64(cpu_HI[0], t0, t1);
gen_set_label(l1);
TCGv t2 = tcg_temp_new();
TCGv t3 = tcg_temp_new();
tcg_gen_setcondi_tl(TCG_COND_EQ, t2, t0, -1LL << 63);
tcg_gen_setcondi_tl(TCG_COND_EQ, t3, t1, -1LL);
tcg_gen_and_tl(t2, t2, t3);
tcg_gen_setcondi_tl(TCG_COND_EQ, t3, t1, 0);
tcg_gen_or_tl(t2, t2, t3);
tcg_gen_movi_tl(t3, 0);
tcg_gen_movcond_tl(TCG_COND_NE, t1, t2, t3, t2, t1);
tcg_gen_div_tl(cpu_LO[0], t0, t1);
tcg_gen_rem_tl(cpu_HI[0], t0, t1);
tcg_temp_free(t3);
tcg_temp_free(t2);
}
opn = "ddiv";
break;
case OPC_DDIVU:
{
int l1 = gen_new_label();
tcg_gen_brcondi_tl(TCG_COND_EQ, t1, 0, l1);
TCGv t2 = tcg_const_tl(0);
TCGv t3 = tcg_const_tl(1);
tcg_gen_movcond_tl(TCG_COND_EQ, t1, t1, t2, t3, t1);
tcg_gen_divu_i64(cpu_LO[0], t0, t1);
tcg_gen_remu_i64(cpu_HI[0], t0, t1);
gen_set_label(l1);
tcg_temp_free(t3);
tcg_temp_free(t2);
}
opn = "ddivu";
break;