| cmm/CmmLex.x) to understand textual C--. Note that there is also a "new" C--
| representation hanging around that is not too interesting for you, since we
don't
| use it at all without the flag -fnew-codegen.
Although ultimately we hope to move to the new rep and abandon the old one.
Simon
Excerpts from Denys Rtveliashvili's message of Thu Apr 28 04:41:48 -0400 2011:
> Well.. I found some places in C-- compiler which are supposed to convert
> division and multiplication by 2^n into shifts. And I believe these work
> sometimes.
>
> However in this case I am a bit puzzled because eve
Hi David,
---
Question: can't it use cheap multiplication and shift instead of expensive
division here? I know that such optimisation is implemented at least to some
extent for C--. I suppose it also won't do anything smart for expressions
like a*4 or a/4 for the same reason.
T
On 27 April 2011 20:01, Denys Rtveliashvili wrote:
> The lack of expected magic is in the assembler code:
> ---
>
> addq $16,%r12
> cmpq 144(%r13),%r12
> ja .Lcz1
> movl $1117,%ecx
> movl $1113,%r10d
> movl $,%r11d
> movq 7(%rbx),%rax
> cqto
>
On April 27, 2011 23:01:50 Denys Rtveliashvili wrote:
> Question 1: what is the meaning of those magic numbers
> -9223372036854775808, -6677706553, -7418931981405, -8257271295304186?
> Question 2: under which circumstances those strange branches of
> execution will be used and what those results wo
Hi,
While trying to figure out why some of my code is very slow I have found
that it is something related to division.
Digging a bit deeper I found an example which shows some unexpected
magic and a lack of the expected one.
Before raising any tickets in trac I would like to consult with you
r
