[llvm-commits] [llvm] r84033 - in /llvm/trunk/lib/Transforms/Scalar: InstructionCombining.cpp LICM.cpp LoopUnswitch.cpp

[Chris Lattner]

On Oct 13, 2009, at 2:41 PM, Devang Patel wrote:

> Author: dpatel
> Date: Tue Oct 13 16:41:20 2009
> New Revision: 84033
>
> URL: http://llvm.org/viewvc/llvm-project?rev=84033&view=rev
> Log:
> Do not check use_empty() before replaceAllUsesWith(). This gives  
> ValueHandles a chance to get properly updated.

Ok, but two requests:

1. please add a comment that this is updating the uses and the metadata.
2. The code may need to check to see that the call doesn't return  
void.  UndefValue::get(void) is not valid.

-Chris

>
>
> Modified:
>    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
>    llvm/trunk/lib/Transforms/Scalar/LICM.cpp
>    llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp
>
> Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=84033&r1=84032&r2=84033&view=diff
>
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> --- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp  
> (original)
> +++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Tue  
> Oct 13 16:41:20 2009
> @@ -9979,8 +9979,7 @@
>       new StoreInst(ConstantInt::getTrue(*Context),
>                 UndefValue::get(Type::getInt1PtrTy(*Context)),
>                                   OldCall);
> -      if (!OldCall->use_empty())
> -        OldCall->replaceAllUsesWith(UndefValue::get(OldCall- 
> >getType()));
> +      OldCall->replaceAllUsesWith(UndefValue::get(OldCall- 
> >getType()));
>       if (isa<CallInst>(OldCall))   // Not worth removing an invoke  
> here.
>         return EraseInstFromFunction(*OldCall);
>       return 0;
> @@ -9994,9 +9993,8 @@
>                UndefValue::get(Type::getInt1PtrTy(*Context)),
>                   CS.getInstruction());
>
> -    if (!CS.getInstruction()->use_empty())
> -      CS.getInstruction()->
> -        replaceAllUsesWith(UndefValue::get(CS.getInstruction()- 
> >getType()));
> +    CS.getInstruction()->
> +      replaceAllUsesWith(UndefValue::get(CS.getInstruction()- 
> >getType()));
>
>     if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
>       // Don't break the CFG, insert a dummy cond branch.
> @@ -10251,7 +10249,7 @@
>     }
>   }
>
> -
> +
>   if (!Caller->use_empty())
>     Caller->replaceAllUsesWith(NV);
>
> @@ -10398,7 +10396,7 @@
>           setCallingConv(cast<CallInst>(Caller)->getCallingConv());
>         cast<CallInst>(NewCaller)->setAttributes(NewPAL);
>       }
> -      if (Caller->getType() != Type::getVoidTy(*Context) && !Caller- 
> >use_empty())
> +      if (Caller->getType() != Type::getVoidTy(*Context))
>         Caller->replaceAllUsesWith(NewCaller);
>       Caller->eraseFromParent();
>       Worklist.Remove(Caller);
> @@ -12781,8 +12779,7 @@
>             ++NumDeadInst;
>             MadeIRChange = true;
>           }
> -          if (!I->use_empty())
> -            I->replaceAllUsesWith(UndefValue::get(I->getType()));
> +          I->replaceAllUsesWith(UndefValue::get(I->getType()));
>           I->eraseFromParent();
>         }
>       }
>
> Modified: llvm/trunk/lib/Transforms/Scalar/LICM.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LICM.cpp?rev=84033&r1=84032&r2=84033&view=diff
>
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> --- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Tue Oct 13 16:41:20 2009
> @@ -486,8 +486,8 @@
>     if (!isExitBlockDominatedByBlockInLoop(ExitBlocks[0],  
> I.getParent())) {
>       // Instruction is not used, just delete it.
>       CurAST->deleteValue(&I);
> -      if (!I.use_empty())  // If I has users in unreachable blocks,  
> eliminate.
> -        I.replaceAllUsesWith(UndefValue::get(I.getType()));
> +      // If I has users in unreachable blocks, eliminate.
> +      I.replaceAllUsesWith(UndefValue::get(I.getType()));
>       I.eraseFromParent();
>     } else {
>       // Move the instruction to the start of the exit block, after  
> any PHI
> @@ -499,8 +499,8 @@
>   } else if (ExitBlocks.empty()) {
>     // The instruction is actually dead if there ARE NO exit blocks.
>     CurAST->deleteValue(&I);
> -    if (!I.use_empty())  // If I has users in unreachable blocks,  
> eliminate.
> -      I.replaceAllUsesWith(UndefValue::get(I.getType()));
> +    // If I has users in unreachable blocks, eliminate.
> +    I.replaceAllUsesWith(UndefValue::get(I.getType()));
>     I.eraseFromParent();
>   } else {
>     // Otherwise, if we have multiple exits, use the PromoteMem2Reg  
> function to
>
> Modified: llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp?rev=84033&r1=84032&r2=84033&view=diff
>
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> --- llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/LoopUnswitch.cpp Tue Oct 13  
> 16:41:20 2009
> @@ -781,8 +781,7 @@
>
>     // Anything that uses the instructions in this basic block  
> should have their
>     // uses replaced with undefs.
> -    if (!I->use_empty())
> -      I->replaceAllUsesWith(UndefValue::get(I->getType()));
> +    I->replaceAllUsesWith(UndefValue::get(I->getType()));
>   }
>
>   // If this is the edge to the header block for a loop, remove the  
> loop and
>
>
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