[PATCH] D51392: [IR] add shuffle queries for identity extend/extract

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri accepted this revision.
lebedev.ri added a comment.
This revision is now accepted and ready to land.

I think this looks good. Naming suggestion included.



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Comment at: include/llvm/IR/Instructions.h:2508-2514
+  /// Return true if this shuffle extends exactly one source vector with undefs
+  /// in the high elements.
+  bool isIdentityWithExtend() const;
+
+  /// Return true if this shuffle extracts the first N elements of exactly one
+  /// source vector.
+  bool isIdentityWithExtract() const;
----------------
`isIdentityWithExtend()` sounds very much like [[ https://llvm.org/docs/LangRef.html#zext-to-instruction | `zext` ]]-but-with-undef.
So maybe `isIdentityWithExtract()` can follow suit and be named `isIdentityWithTruncate()`?


https://reviews.llvm.org/D51392