While swapping constants to the second operand, swap
sources matching destinations to the first operand.
Signed-off-by: Richard Henderson <r...@twiddle.net>
---
tcg/optimize.c | 22 +++++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index 5b0a8ce..becc408 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -337,6 +337,8 @@ 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.
If this temp is a copy of other ones then this equivalence class'
@@ -363,7 +365,8 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t
*tcg_opc_ptr,
}
}
- /* For commutative operations make constant second argument */
+ /* For commutative operations make constant second argument, or
+ if the destination is an input, make it the first argument. */
switch (op) {
CASE_OP_32_64(add):
CASE_OP_32_64(mul):
@@ -373,7 +376,9 @@ 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):
- if (temps[args[1]].state == TCG_TEMP_CONST) {
+ if (temps[args[1]].state == TCG_TEMP_CONST
+ || (args[0] == args[2]
+ && temps[args[1]].state != TCG_TEMP_CONST)) {
tmp = args[1];
args[1] = args[2];
args[2] = tmp;
@@ -398,13 +403,24 @@ static TCGArg *tcg_constant_folding(TCGContext *s,
uint16_t *tcg_opc_ptr,
}
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;
- args[5] = tcg_swap_cond(args[5]);
+ cond = tcg_swap_cond(cond);
+ }
+ /* 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);
}
+ args[5] = cond;
default:
break;
}
--
1.7.11.4
