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[Qemu-devel] [PATCH 01/10] tcg: Split out swap_commutative as a subrouti
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 01/10] tcg: Split out swap_commutative as a subroutine |
Date: |
Tue, 2 Oct 2012 11:32:21 -0700 |
Reduces code duplication and prefers
movcond d, c1, c2, const, s
to
movcond d, c1, c2, s, const
It also prefers
add r, r, c
over
add r, c, r
when both inputs are known constants. This doesn't matter for true add, as
we will fully constant fold that. But it matters for a follow-on patch using
this routine for add2 which may not be fully foldable.
Signed-off-by: Richard Henderson <address@hidden>
---
tcg/optimize.c | 56 ++++++++++++++++++++++++--------------------------------
1 file changed, 24 insertions(+), 32 deletions(-)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index 35532a1..5e0504a 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -382,6 +382,23 @@ static TCGArg do_constant_folding_cond(TCGOpcode op,
TCGArg x,
tcg_abort();
}
+static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
+{
+ TCGArg a1 = *p1, a2 = *p2;
+ int sum = 0;
+ sum += temps[a1].state == TCG_TEMP_CONST;
+ sum -= temps[a2].state == TCG_TEMP_CONST;
+
+ /* Prefer the constant in second argument, and then the form
+ op a, a, b, which is better handled on non-RISC hosts. */
+ if (sum > 0 || (sum == 0 && dest == a2)) {
+ *p1 = a2;
+ *p2 = a1;
+ return true;
+ }
+ return false;
+}
+
/* Propagate constants and copies, fold constant expressions. */
static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
TCGArg *args, TCGOpDef *tcg_op_defs)
@@ -391,7 +408,6 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t
*tcg_opc_ptr,
const TCGOpDef *def;
TCGArg *gen_args;
TCGArg tmp;
- TCGCond cond;
/* Array VALS has an element for each temp.
If this temp holds a constant then its value is kept in VALS' element.
@@ -434,52 +450,28 @@ static TCGArg *tcg_constant_folding(TCGContext *s,
uint16_t *tcg_opc_ptr,
CASE_OP_32_64(eqv):
CASE_OP_32_64(nand):
CASE_OP_32_64(nor):
- /* Prefer the constant in second argument, and then the form
- op a, a, b, which is better handled on non-RISC hosts. */
- if (temps[args[1]].state == TCG_TEMP_CONST || (args[0] == args[2]
- && temps[args[2]].state != TCG_TEMP_CONST)) {
- tmp = args[1];
- args[1] = args[2];
- args[2] = tmp;
- }
+ swap_commutative(args[0], &args[1], &args[2]);
break;
CASE_OP_32_64(brcond):
- if (temps[args[0]].state == TCG_TEMP_CONST
- && temps[args[1]].state != TCG_TEMP_CONST) {
- tmp = args[0];
- args[0] = args[1];
- args[1] = tmp;
+ if (swap_commutative(-1, &args[0], &args[1])) {
args[2] = tcg_swap_cond(args[2]);
}
break;
CASE_OP_32_64(setcond):
- if (temps[args[1]].state == TCG_TEMP_CONST
- && temps[args[2]].state != TCG_TEMP_CONST) {
- tmp = args[1];
- args[1] = args[2];
- args[2] = tmp;
+ if (swap_commutative(args[0], &args[1], &args[2])) {
args[3] = tcg_swap_cond(args[3]);
}
break;
CASE_OP_32_64(movcond):
- cond = args[5];
- if (temps[args[1]].state == TCG_TEMP_CONST
- && temps[args[2]].state != TCG_TEMP_CONST) {
- tmp = args[1];
- args[1] = args[2];
- args[2] = tmp;
- cond = tcg_swap_cond(cond);
+ if (swap_commutative(-1, &args[1], &args[2])) {
+ args[5] = tcg_swap_cond(args[5]);
}
/* For movcond, we canonicalize the "false" input reg to match
the destination reg so that the tcg backend can implement
a "move if true" operation. */
- if (args[0] == args[3]) {
- tmp = args[3];
- args[3] = args[4];
- args[4] = tmp;
- cond = tcg_invert_cond(cond);
+ if (swap_commutative(args[0], &args[4], &args[3])) {
+ args[5] = tcg_invert_cond(args[5]);
}
- args[5] = cond;
default:
break;
}
--
1.7.11.4
[Qemu-devel] [PATCH 03/10] tcg: Swap commutative double-word comparisons, Richard Henderson, 2012/10/02
[Qemu-devel] [PATCH 02/10] tcg: Canonicalize add2 operand ordering, Richard Henderson, 2012/10/02