[llvm-commits] [llvm] r95739 - in /llvm/trunk/lib/CodeGen: LiveIntervalAnalysis.cpp SimpleRegisterCoalescing.cpp

[Dale Johannesen]

On Feb 9, 2010, at 5:11 PMPST, Chris Lattner wrote:

> On Feb 9, 2010, at 4:55 PM, Dale Johannesen wrote:
>> URL: http://llvm.org/viewvc/llvm-project?rev=95739&view=rev
>> Log:
>> Skip DBG_VALUE many places in live intervals and
>> register coalescing.  This fixes many crashes and
>> places where debug info affects codegen (when
>> dbg.value is lowered to machine instructions, which
>> it isn't yet in TOT).
>
> Ok.
>
>> +  MachineBasicBlock::iterator E = MBB->end();
>> +  while (mi != E) {
>> +    if (!mi->isDebugValue()) {
>
> Can't this use continue like this:
>
> if (!mi->isDebugValue()) {
>  ++mi;
>  continue;
> }

It could.  I feel pretty strongly it's easier to read this way, but  
it's not worth arguing about.

>> +      if (mi->killsRegister(interval.reg, tri_)) {
>> +        DEBUG(dbgs() << " killed");
>> +        end = baseIndex.getDefIndex();
>> +        SeenDefUse = true;
>> +        break;
>> +      } else if (mi->modifiesRegister(interval.reg, tri_)) {
>> +        // Another instruction redefines the register before it is  
>> ever read.
>> +        // Then the register is essentially dead at the  
>> instruction that defines
>> +        // it. Hence its interval is:
>> +        // [defSlot(def), defSlot(def)+1)
>> +        DEBUG(dbgs() << " dead");
>> +        end = start.getStoreIndex();
>> +        SeenDefUse = true;
>> +        break;
>> +      }
>> +    }
>>
>