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author | Richard Henderson <rth@twiddle.net> | 2012-10-02 11:32:27 -0700 |
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committer | Aurelien Jarno <aurelien@aurel32.net> | 2012-10-17 17:51:35 +0200 |
commit | 6c4382f8f47d12eec24c7c5335141a9c78104016 (patch) | |
tree | b253a98e3f7f22a7d6e7c290ef2a795931b9252b | |
parent | 9519da7e39516c5cb5bd7146a849a5d8c0958105 (diff) | |
download | qemu-6c4382f8f47d12eec24c7c5335141a9c78104016.zip qemu-6c4382f8f47d12eec24c7c5335141a9c78104016.tar.gz qemu-6c4382f8f47d12eec24c7c5335141a9c78104016.tar.bz2 |
tcg: Do constant folding on double-word comparisons
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
-rw-r--r-- | tcg/optimize.c | 93 |
1 files changed, 72 insertions, 21 deletions
diff --git a/tcg/optimize.c b/tcg/optimize.c index 38027dc..d9251e4 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -398,6 +398,40 @@ static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x, } } +/* Return 2 if the condition can't be simplified, and the result + of the condition (0 or 1) if it can */ +static TCGArg do_constant_folding_cond2(TCGArg *p1, TCGArg *p2, TCGCond c) +{ + TCGArg al = p1[0], ah = p1[1]; + TCGArg bl = p2[0], bh = p2[1]; + + if (temps[bl].state == TCG_TEMP_CONST + && temps[bh].state == TCG_TEMP_CONST) { + uint64_t b = ((uint64_t)temps[bh].val << 32) | (uint32_t)temps[bl].val; + + if (temps[al].state == TCG_TEMP_CONST + && temps[ah].state == TCG_TEMP_CONST) { + uint64_t a; + a = ((uint64_t)temps[ah].val << 32) | (uint32_t)temps[al].val; + return do_constant_folding_cond_64(a, b, c); + } + if (b == 0) { + switch (c) { + case TCG_COND_LTU: + return 0; + case TCG_COND_GEU: + return 1; + default: + break; + } + } + } + if (temps_are_copies(al, bl) && temps_are_copies(ah, bh)) { + return do_constant_folding_cond_eq(c); + } + return 2; +} + static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2) { TCGArg a1 = *p1, a2 = *p2; @@ -763,43 +797,60 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, goto do_default; 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[3]].val == 0) { + tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]); + if (tmp != 2) { + if (tmp) { + memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info)); + gen_opc_buf[op_index] = INDEX_op_br; + gen_args[0] = args[5]; + gen_args += 1; + } else { + gen_opc_buf[op_index] = INDEX_op_nop; + } + } else 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[3]].val == 0) { + /* Simplify LT/GE comparisons vs zero to a single compare + vs the high word of the input. */ + memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info)); gen_opc_buf[op_index] = INDEX_op_brcond_i32; gen_args[0] = args[1]; gen_args[1] = args[3]; gen_args[2] = args[4]; gen_args[3] = args[5]; gen_args += 4; - args += 6; - memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info)); - break; + } else { + goto do_default; } - goto do_default; + 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) { + tmp = do_constant_folding_cond2(&args[1], &args[3], args[5]); + if (tmp != 2) { + gen_opc_buf[op_index] = INDEX_op_movi_i32; + tcg_opt_gen_movi(gen_args, args[0], tmp); + gen_args += 2; + } else 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) { + /* Simplify LT/GE comparisons vs zero to a single compare + vs the high word of the input. */ gen_opc_buf[op_index] = INDEX_op_setcond_i32; gen_args[0] = args[0]; gen_args[1] = args[2]; gen_args[2] = args[4]; gen_args[3] = args[5]; gen_args += 4; - args += 6; - break; + } else { + goto do_default; } - goto do_default; + args += 6; + break; case INDEX_op_call: nb_call_args = (args[0] >> 16) + (args[0] & 0xffff); |