Message ID | 1348084823-18277-9-git-send-email-aurelien@aurel32.net |
---|---|
State | New |
Headers | show |
On 09/19/2012 01:00 PM, Aurelien Jarno wrote: > The "op a, a, b" form is better handled on non-RISC host than the "op > a, b, a" form, so swap the arguments to this form when possible, and > when b is not a constant. > > This reduces the number of generated instructions by a tiny bit. > > Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> Reviewed-by: Richard Henderson <rth@twiddle.net> r~
diff --git a/tcg/optimize.c b/tcg/optimize.c index 6e2a37d..3495b7a 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -432,7 +432,10 @@ 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) { + /* 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;
The "op a, a, b" form is better handled on non-RISC host than the "op a, b, a" form, so swap the arguments to this form when possible, and when b is not a constant. This reduces the number of generated instructions by a tiny bit. Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> --- tcg/optimize.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)