[PATCH] D122077: [InstCombine] Fold (ctpop(X) == 1) | (X == 0) into ctpop(X) < 2

[Sanjay Patel via Phabricator via cfe-commits]

spatel added inline comments.


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp:916
+/// fold (icmp ne ctpop(X) 1) & (icmp ne X 0) into (icmp uge ctpop(X) 2).
+static Value *foldOrOfCtpop(ICmpInst *Cmp0, ICmpInst *Cmp1, bool IsAnd,
+                            InstCombiner::BuilderTy &Builder) {
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This name is too specific now that we are handling 'and'. It could be called "foldIsPowerOf2OrZero" to match the transform below?


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Comment at: llvm/test/Transforms/InstCombine/ispow2.ll:540
 
 define i1 @isnot_pow2_ctpop_wrong_pred1(i32 %x) {
 ; CHECK-LABEL: @isnot_pow2_ctpop_wrong_pred1(
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It seems better to rename this test and the next one now that we can optimize it - "is_pow2_or_zero"  or similar.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D122077/new/

https://reviews.llvm.org/D122077