Message ID | 1348766397-20731-5-git-send-email-rth@twiddle.net |
---|---|
State | New |
Headers | show |
On Thu, Sep 27, 2012 at 10:19:54AM -0700, Richard Henderson wrote: > Signed-off-by: Richard Henderson <rth@twiddle.net> > --- > tcg/optimize.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 51 insertions(+) > > diff --git a/tcg/optimize.c b/tcg/optimize.c > index d39926e..c972e4f 100644 > --- a/tcg/optimize.c > +++ b/tcg/optimize.c > @@ -799,6 +799,57 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, > } > args += 6; > break; > + case INDEX_op_brcond2_i32: > + /* Simplify LT/GE comparisons vs zero to a single compare > + vs the high word of the input. */ > + if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE) > + && temps[args[2]].state == TCG_TEMP_CONST > + && temps[args[3]].state == TCG_TEMP_CONST > + && temps[args[2]].val == 0 > + && temps[args[2]].val == 0) { The value comparison there is wrong, probably copy & paste issue. I wonder how it could work. > + gen_opc_buf[op_index] = INDEX_op_brcond_i32; > + args[0] = args[1]; > + args[1] = args[3]; > + args[2] = args[4]; > + args[3] = args[5]; > + gen_args += 4; > + } else { > + gen_args[0] = args[0]; > + gen_args[1] = args[1]; > + gen_args[2] = args[2]; > + gen_args[3] = args[3]; > + gen_args[4] = args[4]; > + gen_args[5] = args[5]; > + gen_args += 6; > + } > + memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info)); > + args += 6; > + break; > + case INDEX_op_setcond2_i32: > + /* Simplify LT/GE comparisons vs zero to a single compare > + vs the high word of the input. */ > + if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE) > + && temps[args[3]].state == TCG_TEMP_CONST > + && temps[args[4]].state == TCG_TEMP_CONST > + && temps[args[3]].val == 0 > + && temps[args[4]].val == 0) { Here it is fine. > + gen_opc_buf[op_index] = INDEX_op_setcond_i32; > + args[1] = args[2]; > + args[2] = args[4]; > + args[3] = args[5]; > + gen_args += 4; > + } else { > + reset_temp(args[0]); > + gen_args[0] = args[0]; > + gen_args[1] = args[1]; > + gen_args[2] = args[2]; > + gen_args[3] = args[3]; > + gen_args[4] = args[4]; > + gen_args[5] = args[5]; > + gen_args += 6; > + } > + args += 6; > + break; > case INDEX_op_call: > nb_call_args = (args[0] >> 16) + (args[0] & 0xffff); > if (!(args[nb_call_args + 1] & (TCG_CALL_CONST | TCG_CALL_PURE))) { While it's a nice optimization to have, one that seems to happen a lot more often is the two high parts being equal. It happens when the guest is working on (u)int32_t.
On 2012-10-01 11:43, Aurelien Jarno wrote: > While it's a nice optimization to have, one that seems to happen a lot > more often is the two high parts being equal. It happens when the guest > is working on (u)int32_t. It depends on what target you're looking at. For alpha guest, all branches are comparisons vs zero, so LT/GE happens with some regularity. r~
diff --git a/tcg/optimize.c b/tcg/optimize.c index d39926e..c972e4f 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -799,6 +799,57 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, } args += 6; break; + case INDEX_op_brcond2_i32: + /* Simplify LT/GE comparisons vs zero to a single compare + vs the high word of the input. */ + if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE) + && temps[args[2]].state == TCG_TEMP_CONST + && temps[args[3]].state == TCG_TEMP_CONST + && temps[args[2]].val == 0 + && temps[args[2]].val == 0) { + gen_opc_buf[op_index] = INDEX_op_brcond_i32; + args[0] = args[1]; + args[1] = args[3]; + args[2] = args[4]; + args[3] = args[5]; + gen_args += 4; + } else { + gen_args[0] = args[0]; + gen_args[1] = args[1]; + gen_args[2] = args[2]; + gen_args[3] = args[3]; + gen_args[4] = args[4]; + gen_args[5] = args[5]; + gen_args += 6; + } + memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info)); + args += 6; + break; + case INDEX_op_setcond2_i32: + /* Simplify LT/GE comparisons vs zero to a single compare + vs the high word of the input. */ + if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE) + && temps[args[3]].state == TCG_TEMP_CONST + && temps[args[4]].state == TCG_TEMP_CONST + && temps[args[3]].val == 0 + && temps[args[4]].val == 0) { + gen_opc_buf[op_index] = INDEX_op_setcond_i32; + args[1] = args[2]; + args[2] = args[4]; + args[3] = args[5]; + gen_args += 4; + } else { + reset_temp(args[0]); + gen_args[0] = args[0]; + gen_args[1] = args[1]; + gen_args[2] = args[2]; + gen_args[3] = args[3]; + gen_args[4] = args[4]; + gen_args[5] = args[5]; + gen_args += 6; + } + args += 6; + break; case INDEX_op_call: nb_call_args = (args[0] >> 16) + (args[0] & 0xffff); if (!(args[nb_call_args + 1] & (TCG_CALL_CONST | TCG_CALL_PURE))) {
Signed-off-by: Richard Henderson <rth@twiddle.net> --- tcg/optimize.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+)