Displaying 5 results from an estimated 5 matches for "visitfdiv".
2013 Aug 08
3
[LLVMdev] Convert fdiv - X/Y -> X*1/Y
I remember why I didn't implement this rule in Instcombine. It add one
instruction. So,
this xform should be driven by a redundancy eliminator if you care code
size.
On 8/8/13 10:13 AM, Shuxin Yang wrote:
> I did few transformation in Instruction *InstCombiner::visitFDiv() in
> an attempt to remove some divs.
> I may miss this case. If you need to implement this rule, it is
> better done in Instcombine than in DAG combine.
> Doing such xform early expose the redundancy of 1/y, which have
> positive impact to neighboring code,
> while DAG combi...
2013 Aug 08
0
[LLVMdev] Convert fdiv - X/Y -> X*1/Y
I did few transformation in Instruction *InstCombiner::visitFDiv() in an
attempt to remove some divs.
I may miss this case. If you need to implement this rule, it is better
done in Instcombine than in DAG combine.
Doing such xform early expose the redundancy of 1/y, which have positive
impact to neighboring code,
while DAG combine is bit blind.
You should b...
2013 Aug 08
0
[LLVMdev] Convert fdiv - X/Y -> X*1/Y
...e:
> I remember why I didn't implement this rule in Instcombine. It add one instruction. So,
> this xform should be driven by a redundancy eliminator if you care code size.
>
> On 8/8/13 10:13 AM, Shuxin Yang wrote:
>> I did few transformation in Instruction *InstCombiner::visitFDiv() in an attempt to remove some divs.
>> I may miss this case. If you need to implement this rule, it is better done in Instcombine than in DAG combine.
>> Doing such xform early expose the redundancy of 1/y, which have positive impact to neighboring code,
>> while DAG combine...
2017 Mar 06
2
combineRepeatedFPDivisors design questions
Hello,
Recently I have stumbled across an almost double performance decrease in one of my codebases when compiling with clang instead of gcc. I was testing with the currently latest 3.9.1 as well as 4.0.0 rc2 targeting x86-64 darwin with -Ofast, and after some investigation was able to narrow down the code to the following snippet:
__attribute__ ((noinline)) bool calculate(double c) {
uint32_t
2013 Aug 08
13
[LLVMdev] Convert fdiv - X/Y -> X*1/Y
I would like to transform X/Y -> X*1/Y. Specifically, I would like to
convert:
define void @t1a(double %a, double %b, double %d) {
entry:
%div = fdiv fast double %a, %d
%div1 = fdiv fast double %b, %d
%call = tail call i32 @foo(double %div, double %div1)
ret void
}
to:
define void @t1b(double %a, double %b, double %d) {
entry:
%div = fdiv fast double 1.000000e+00, %d
%mul = fmul