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[Qemu-devel] [PATCH 7/7] tcg: Do constant folding on double-word compari
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 7/7] tcg: Do constant folding on double-word comparisons |
Date: |
Thu, 27 Sep 2012 10:19:57 -0700 |
Signed-off-by: Richard Henderson <address@hidden>
---
tcg/optimize.c | 134 ++++++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 94 insertions(+), 40 deletions(-)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index dfac877..f6a16fd 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;
@@ -816,53 +850,73 @@ 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;
+ tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]);
+ if (tmp != 2) {
+ if (tmp) {
+ 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;
+ args += 6;
+ break;
+ }
} 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;
+ /* 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;
+ 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 {
- 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;
+ /* 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;
--
1.7.11.4
- [Qemu-devel] [PATCH 0/7] Double-word tcg/optimize improvements, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 1/7] tcg: Split out swap_commutative as a subroutine, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 2/7] tcg: Optimize add2 + sub2, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 4/7] tcg: Optimize double-word comparisons against zero, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 7/7] tcg: Do constant folding on double-word comparisons,
Richard Henderson <=
- [Qemu-devel] [PATCH 6/7] tcg: Tidy brcond optimization, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 3/7] tcg: Swap commutative double-word comparisons, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 5/7] tcg: Split out subroutines from do_constant_folding_cond, Richard Henderson, 2012/09/27