[PATCH] D78568: [DAGCombine] Fix bug in load scalarization

[Fraser Cormack via Phabricator via llvm-commits]

frasercrmck added a comment.

In D78568#2350310 <https://reviews.llvm.org/D78568#2350310>, @foad wrote:

> In D78568#2350291 <https://reviews.llvm.org/D78568#2350291>, @frasercrmck wrote:
>
>> In D78568#2349707 <https://reviews.llvm.org/D78568#2349707>, @foad wrote:
>>
>>> Looks good to me. You could pre-commit the test case and rebase this diff so we can see the effect on codegen.
>>
>> Sure, I can do that. Is committing a test that "expects" incorrect codegen the done thing?
>
> Yes, especially if it's only temporary and the checks are generated.

Okay, great. The test is currently generated as:

  define i1 @extractloadi1(<8 x i1> *%ptr, i32 %idx) {
  ; CHECK-LABEL: extractloadi1:
  ; CHECK:       ; %bb.0:
  ; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
  ; CHECK-NEXT:    v_mad_u64_u32 v[0:1], s[4:5], v2, 1, v[0:1]
  ; CHECK-NEXT:    flat_load_ubyte v0, v[0:1]
  ; CHECK-NEXT:    s_waitcnt vmcnt(0) lgkmcnt(0)
  ; CHECK-NEXT:    s_setpc_b64 s[30:31]
    %val = load <8 x i1>, <8 x i1> *%ptr
    %ret = extractelement <8 x i1> %val, i32 %idx
    ret i1 %ret
  }

I believe this shows the incorrect codegen.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D78568/new/

https://reviews.llvm.org/D78568