[PATCH] D64142: [SLP] try to create vector loads from bitcasted scalar pointers

[Sanjay Patel via Phabricator via llvm-commits]

spatel marked an inline comment as done.
spatel added inline comments.


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Comment at: llvm/test/Transforms/SLPVectorizer/X86/load-bitcast-vec.ll:7
 ; CHECK-LABEL: @matching_scalar(
-; CHECK-NEXT:    [[BC:%.*]] = bitcast <4 x float>* [[P:%.*]] to float*
-; CHECK-NEXT:    [[R:%.*]] = load float, float* [[BC]], align 16
-; CHECK-NEXT:    ret float [[R]]
+; CHECK-NEXT:    [[TMP1:%.*]] = load <4 x float>, <4 x float>* [[P:%.*]], align 16
+; CHECK-NEXT:    [[TMP2:%.*]] = extractelement <4 x float> [[TMP1]], i32 0
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ABataev wrote:
> Seems to me, it must be masked load rather than just load. Plus, what about the cost? This does not look like cost optimal.
If the load is guaranteed dereferenceable, does that not allow speculated load of the entire vector?

I'm open to suggestions about the cost calc. It's not clear to me if there's an existing TTI API for this or if we need to create a new one?


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  https://reviews.llvm.org/D64142/new/

https://reviews.llvm.org/D64142