[PATCH] D28934: Write a new SSAUpdater

[Davide Italiano via Phabricator via llvm-commits]

davide added a comment.

In https://reviews.llvm.org/D28934#768477, @davide wrote:

> @dberlin I just came back to this while I was looking at NewGVN PRE.
>  I decided to give it a try to see how the API looked like and I personally didn't find any problems with it (I might just used it wrong, FWIW).
>
> https://reviews.llvm.org/P7997
>
> In particular, the old API `getValueInTheMiddleOfTheBlock` has been source of confusion (at least to me).
>
> With your patch and my patch on top of it, I saw still one test failing:
>
>   --- /home/davide/old.ll 2017-05-30 20:56:21.058869000 -0700
>   +++ /home/davide/new.ll 2017-05-30 20:56:30.450514797 -0700
>   @@ -316,7 +316,7 @@
>      br label %block4
>  
>    block4:                                           ; preds = %block3, %block2
>   -  %D = phi i32 [ 87, %block2 ], [ 97, %block3 ]
>   +  %D = phi i32 [ 97, %block3 ], [ 87, %block2 ]
>      %A = phi i32 [ -1, %block2 ], [ 42, %block3 ]
>      br i1 %cmpxy, label %block5, label %exit
>  
>   @@ -350,7 +350,7 @@
>      br label %loop
>  
>    loop:                                             ; preds = %loop, %entry
>   -  %Y2 = phi i8 [ %Y, %entry ], [ 0, %loop ]
>   +  %Y2 = phi i8 [ 0, %loop ], [ %Y, %entry ]
>      %i = phi i32 [ 4, %entry ], [ 192, %loop ]
>      %X2 = getelementptr i8, i8* %p, i32 %i
>      %cond = call i1 @cond2()
>   @@ -372,7 +372,7 @@
>      br label %loop
>  
>    loop:                                             ; preds = %cont, %entry
>   -  %Y2 = phi i8 [ %Y, %entry ], [ %Y2.pre, %cont ]
>   +  %Y2 = phi i8 [ %Y2.pre, %cont ], [ %Y, %entry ]
>      %i = phi i32 [ 4, %entry ], [ 3, %cont ]
>      %X2 = getelementptr i8, i8* %p, i32 %i
>      %cond = call i1 @cond2()
>
>
> I guess this is because we don't have a consistent ordering of PHI args. If that's the only problem, I might consider looking at it next (and then keep converting the remaining users).


ping on my last comment, in case it got lost in the churn :)


https://reviews.llvm.org/D28934