[PATCH] D106667: SROA: Enhance speculateSelectInstLoads

[Christudasan Devadasan via Phabricator via llvm-commits]

cdevadas added a comment.

I reverted the patch for now.
Missed the case when both bitcasted and non-bitcasted loads can exist at the same time.
In my patch, I should have retained the original TV and FV values rather than overwriting them with the new bitcast instructions. They are required for the non-bitcasted loads.
The loop for select users makes sense. I will upload a new patch.

  ; opt -S -sroa bug.ll -o out.ll
  
  %struct.lookup_args = type { i32, i32* }
  
  define void @arg_lookup(i1 %cmp){
  entry:
    %args = alloca [2 x %struct.lookup_args], align 16
    %ptr = bitcast [2 x %struct.lookup_args]* %args to i8*
    %arraydecay = getelementptr inbounds [2 x %struct.lookup_args], [2 x %struct.lookup_args]* %args, i64 0, i64 0
    %add.ptr = getelementptr inbounds [2 x %struct.lookup_args], [2 x %struct.lookup_args]* %args, i64 0, i64 1
    %cond = select i1 %cmp, %struct.lookup_args* %add.ptr, %struct.lookup_args* %arraydecay
    %addr.i = getelementptr inbounds %struct.lookup_args, %struct.lookup_args* %cond, i64 0, i32 1
    %bcast.i8 = bitcast i32** %addr.i to i8**
    %addr.i8 = load i8*, i8** %bcast.i8, align 8
    call void @foo_i8(i8* %addr.i8)
    %addr.i32 = load i32*, i32** %addr.i, align 8
    call void @foo_i32 (i32* %addr.i32)
    ret void
  }
  
  declare void @foo_i8(i8*)
  declare void @foo_i32(i32*)


Repository:
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https://reviews.llvm.org/D106667