[llvm-commits] [llvm] r83959 - in /llvm/trunk: lib/Analysis/BasicAliasAnalysis.cpp test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll

[Owen Anderson]

Nick,

This shouldn't be necessary.  Duncan and I did the same things back in  
r63900 andr64551.

--Owen

On Oct 13, 2009, at 12:48 AM, Nick Lewycky wrote:

> Author: nicholas
> Date: Tue Oct 13 02:48:38 2009
> New Revision: 83959
>
> URL: http://llvm.org/viewvc/llvm-project?rev=83959&view=rev
> Log:
> Teach BasicAA a little something about the atomic intrinsics: they  
> can only
> modify through the pointer they're given.
>
> Added:
>    llvm/trunk/test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll
> Modified:
>    llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
>
> Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=83959&r1=83958&r2=83959&view=diff
>
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> --- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
> +++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Tue Oct 13  
> 02:48:38 2009
> @@ -284,6 +284,27 @@
>       if (!passedAsArg)
>         return NoModRef;
>     }
> +
> +    if (IntrinsicInst *II = dyn_cast<IntrinsicInst> 
> (CS.getInstruction())) {
> +      switch (II->getIntrinsicID()) {
> +      default: break;
> +      case Intrinsic::atomic_cmp_swap:
> +      case Intrinsic::atomic_swap:
> +      case Intrinsic::atomic_load_add:
> +      case Intrinsic::atomic_load_sub:
> +      case Intrinsic::atomic_load_and:
> +      case Intrinsic::atomic_load_nand:
> +      case Intrinsic::atomic_load_or:
> +      case Intrinsic::atomic_load_xor:
> +      case Intrinsic::atomic_load_max:
> +      case Intrinsic::atomic_load_min:
> +      case Intrinsic::atomic_load_umax:
> +      case Intrinsic::atomic_load_umin:
> +        if (alias(II->getOperand(1), Size, P, Size) == NoAlias)
> +          return NoModRef;
> +        break;
> +      }
> +    }
>   }
>
>   // The AliasAnalysis base class has some smarts, lets use them.
>
> Added: llvm/trunk/test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll?rev=83959&view=auto
>
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> --- llvm/trunk/test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll  
> (added)
> +++ llvm/trunk/test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll Tue  
> Oct 13 02:48:38 2009
> @@ -0,0 +1,16 @@
> +; RUN: opt -gvn -S < %s | FileCheck %s
> +
> +declare i8 @llvm.atomic.load.add.i8.p0i8(i8*, i8)
> +
> +define void @foo(i8* %ptr) {
> +  %P = getelementptr i8* %ptr, i32 0
> +  %Q = getelementptr i8* %ptr, i32 1
> +; CHECK: getelementptr
> +  %X = load i8* %P
> +; CHECK: = load
> +  %Y = call i8 @llvm.atomic.load.add.i8.p0i8(i8* %Q, i8 1)
> +  %Z = load i8* %P
> +; CHECK-NOT: = load
> +  ret void
> +; CHECK: ret void
> +}
>
>
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