Hi Andrew,
You mean using a DI rotate left by 4 and then saving the output as SI
(saving the hi part and ignoring the low one) ?
Also, how is canonicalization detected anyway? Are there rules that gcc
follows? How can they be changed?
Sami
Andrew Pinski wrote:
output = (operand1 28) |
On Wed, Feb 14, 2007 at 08:30:52PM +, Sami Khawam wrote:
Hi Rask,
Basically the CPU has the 'SCALE_28_4' instruction which does the following:
output = (operand1 28) | (operand2 4)
From my understanding the OR operation (ior), doesn't get canonicalized
since it's second operand
OK, I see what you mean. The reason you can get both (ior (ashift ...)
(lshiftrt ...)) and (ior (lshiftrt ...) (ashift ...)) is that simplify-rtx.c
has no rule to canonicalize such expressions and that LSHIFTRT and
ASHIFT have the same precedence.
Hmm, in simplify_binary_operation_1(), it
Hi,
Although I have been porting and using gcc for quite a while now, I am
still a newbie at the internals and would be grateful if you can help me.
I have designed a CPU architecture where most of the instructions only
accept data operands as registers and no immediate values are allowed,
On Wed, Feb 14, 2007 at 05:31:36PM +, Sami Khawam wrote:
(define_insn scale_28_4
[(set (match_operand:SI 0 register_operand =r)
(ior:SI
(ashift:SI (match_operand:SI 1 register_operand r)
(const_int 28 ))
(lshiftrt:SI (match_operand:SI 2 register_operand r)
Hi Rask,
Basically the CPU has the 'SCALE_28_4' instruction which does the following:
output = (operand1 28) | (operand2 4)
From my understanding the OR operation (ior), doesn't get canonicalized
since it's second operand (in this case (lshiftrt:SI (match_operand:SI 2
register_operand r)
Hi Rask,
Basically the CPU has the 'SCALE_28_4' instruction which does the following:
output = (operand1 28) | (operand2 4)
Isn't that a rotate? if so you can use either rotate or rotatert instead.
Thanks,
Andrew Pinski
