On 01/07/2016 02:45 PM, Kyrill Tkachov wrote:
On 07/01/16 11:52, Bernd Schmidt wrote:
I looked and this is indeed the case. Still slightly scary. Should the
MEM be rtx_equal_p to TO_RENAME? It would be good to test or at least
assert this.
I tried asserting that and it caused trouble because a bit further up in
noce_process_if_block it does:
/* Only operate on register destinations, and even then avoid extending
the lifetime of hard registers on small register class machines. */
orig_x = x;
if (!REG_P (x)
|| (HARD_REGISTER_P (x)
&& targetm.small_register_classes_for_mode_p (GET_MODE (x))))
{
if (GET_MODE (x) == BLKmode)
return FALSE;
if (GET_CODE (x) == ZERO_EXTRACT
&& (!CONST_INT_P (XEXP (x, 1))
|| !CONST_INT_P (XEXP (x, 2))))
return FALSE;
x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
? XEXP (x, 0) : x));
}
It changes X to a register and after noce_try_cmove_arith it emits the
store.
This suggests that orig_x needs to be passed to bbs_ok_for_cmove_arith,
even disregarding the question of using it to assert that only expected
MEMs are being modified.
Bernd
