[PATCH] D118317: [InstCombine] Fold and-reduce idiom

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev added inline comments.


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp:5910
+  if (!DL.isLegalInteger(NumBits))
+    return nullptr;
+
----------------
RKSimon wrote:
> Why not just use NumBits < getMinVectorRegisterBitWidth()  ?
And what if some platform has scalar types wider than vector types? Theoretically, it's possible I think. Or, say,`i66` is less than `i128`, should be be allowed?

I suggest to leave this thing alone for now. We can have a separate discussion on what is the less restrictive check here. I really don't want this to be blocked by this particular thing.


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Comment at: llvm/test/Transforms/InstCombine/icmp-vec.ll:431
 
 define i1 @eq_cast_ne-1(<2 x i7> %x, <2 x i7> %y) {
 ; CHECK-LABEL: @eq_cast_ne-1(
----------------
spatel wrote:
> If this had a power-of-2 type with this pattern, would we handle it? Would be good to add a few more test comments, so the intent is clear.
> https://alive2.llvm.org/ce/z/rDeaif
> 
> 
Yup. It was going to make this as 2nd step of this activity and support or-base `ne` pattern.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D118317/new/

https://reviews.llvm.org/D118317