[llvm-commits] [PATCH] A fix for the inliner heuristics for recessive calls

[Nadav Rotem]

Hi Hal, 

Because TargetData may not always be available. If TD is unavailable we have no way of knowing the size of arrays of pointers. 

Thanks

On Sep 16, 2012, at 3:44 PM, Hal Finkel <hfinkel at anl.gov> wrote:

> Nadav,
> 
>> +// Do not inline array allocas with more than this many intems into
>> recursive +// function calls.
>> +const int RecursiveArrayAllocThreshold = 128;
> 
> Why is this in items and not in bytes?
> 
> -Hal
> 
> On Sun, 16 Sep 2012 15:16:43 +0300
> Nadav Rotem <nrotem at apple.com> wrote:
> 
>> Hi, 
>> 
>> I am looking at a test case that looks like this:
>> 
>> void foo() {
>>  ... foo();   // I'm recursive!
>> 
>>   bar();
>> }
>> 
>> bar() {  int a[1000];  // large stack size }
>> 
>> If we decide to inline bar() into foo()  we may increase the stack
>> size to the point of overflow.   I attached a patch to prevent
>> inlining of callees which allocate large arrays into a recursive
>> caller. 
>> 
>> Thanks,
>> Nadav 
>> 
>> 
>> 
> 
> 
> 
> -- 
> Hal Finkel
> Postdoctoral Appointee
> Leadership Computing Facility
> Argonne National Laboratory