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authorRichard Henderson <rth@twiddle.net>2014-04-15 22:47:22 -0700
committerRichard Henderson <rth@twiddle.net>2014-05-24 08:47:08 -0700
commit3401fd259e37f08e1333169494bea30ea02a1d63 (patch)
treee8db10d3e5824ee4f548d613428d3caec55f4ea3 /tcg/mips
parent1db1c4d7d91843dd6a7dab93946e01bc19e8ba38 (diff)
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.c77
1 files changed, 20 insertions, 57 deletions
diff --git a/tcg/mips/tcg-target.c b/tcg/mips/tcg-target.c
index ccf262b217..0e5ecf4974 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,