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author | Richard Henderson <rth@twiddle.net> | 2014-04-15 22:47:22 -0700 |
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committer | Richard Henderson <rth@twiddle.net> | 2014-05-24 08:47:08 -0700 |
commit | 3401fd259e37f08e1333169494bea30ea02a1d63 (patch) | |
tree | e8db10d3e5824ee4f548d613428d3caec55f4ea3 /tcg/mips | |
parent | 1db1c4d7d91843dd6a7dab93946e01bc19e8ba38 (diff) | |
download | qemu-3401fd259e37f08e1333169494bea30ea02a1d63.zip qemu-3401fd259e37f08e1333169494bea30ea02a1d63.tar.gz qemu-3401fd259e37f08e1333169494bea30ea02a1d63.tar.bz2 |
tcg-mips: Simplify brcond2
Emitting a single branch instead of (up to) 3, using setcond2
to generate the composite compare.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'tcg/mips')
-rw-r--r-- | tcg/mips/tcg-target.c | 77 |
1 files changed, 20 insertions, 57 deletions
diff --git a/tcg/mips/tcg-target.c b/tcg/mips/tcg-target.c index ccf262b..0e5ecf4 100644 --- a/tcg/mips/tcg-target.c +++ b/tcg/mips/tcg-target.c @@ -764,70 +764,33 @@ static void tcg_out_setcond2(TCGContext *s, TCGCond cond, TCGReg ret, } } -/* XXX: we implement it at the target level to avoid having to - handle cross basic blocks temporaries */ -static void tcg_out_brcond2(TCGContext *s, TCGCond cond, TCGArg arg1, - TCGArg arg2, TCGArg arg3, TCGArg arg4, - int label_index) +static void tcg_out_brcond2(TCGContext *s, TCGCond cond, TCGReg al, TCGReg ah, + TCGReg bl, TCGReg bh, int label_index) { - tcg_insn_unit *label_ptr; + TCGCond b_cond = TCG_COND_NE; + TCGReg tmp = TCG_TMP1; - switch(cond) { - case TCG_COND_NE: - tcg_out_brcond(s, TCG_COND_NE, arg2, arg4, label_index); - tcg_out_brcond(s, TCG_COND_NE, arg1, arg3, label_index); - return; - case TCG_COND_EQ: - break; - case TCG_COND_LT: - case TCG_COND_LE: - tcg_out_brcond(s, TCG_COND_LT, arg2, arg4, label_index); - break; - case TCG_COND_GT: - case TCG_COND_GE: - tcg_out_brcond(s, TCG_COND_GT, arg2, arg4, label_index); - break; - case TCG_COND_LTU: - case TCG_COND_LEU: - tcg_out_brcond(s, TCG_COND_LTU, arg2, arg4, label_index); - break; - case TCG_COND_GTU: - case TCG_COND_GEU: - tcg_out_brcond(s, TCG_COND_GTU, arg2, arg4, label_index); + /* With branches, we emit between 4 and 9 insns with 2 or 3 branches. + With setcond, we emit between 3 and 10 insns and only 1 branch, + which ought to get better branch prediction. */ + switch (cond) { + case TCG_COND_EQ: + case TCG_COND_NE: + b_cond = cond; + tmp = tcg_out_reduce_eq2(s, TCG_TMP0, TCG_TMP1, al, ah, bl, bh); break; - default: - tcg_abort(); - } - - label_ptr = s->code_ptr; - tcg_out_opc_br(s, OPC_BNE, arg2, arg4); - tcg_out_nop(s); - switch(cond) { - case TCG_COND_EQ: - tcg_out_brcond(s, TCG_COND_EQ, arg1, arg3, label_index); - break; - case TCG_COND_LT: - case TCG_COND_LTU: - tcg_out_brcond(s, TCG_COND_LTU, arg1, arg3, label_index); - break; - case TCG_COND_LE: - case TCG_COND_LEU: - tcg_out_brcond(s, TCG_COND_LEU, arg1, arg3, label_index); - break; - case TCG_COND_GT: - case TCG_COND_GTU: - tcg_out_brcond(s, TCG_COND_GTU, arg1, arg3, label_index); - break; - case TCG_COND_GE: - case TCG_COND_GEU: - tcg_out_brcond(s, TCG_COND_GEU, arg1, arg3, label_index); - break; default: - tcg_abort(); + /* Minimize code size by prefering a compare not requiring INV. */ + if (mips_cmp_map[cond] & MIPS_CMP_INV) { + cond = tcg_invert_cond(cond); + b_cond = TCG_COND_EQ; + } + tcg_out_setcond2(s, cond, tmp, al, ah, bl, bh); + break; } - reloc_pc16(label_ptr, s->code_ptr); + tcg_out_brcond(s, b_cond, tmp, TCG_REG_ZERO, label_index); } static void tcg_out_movcond(TCGContext *s, TCGCond cond, TCGReg ret, |