[llvm] [AArch64][GISel] Recover ADDHN from OR comparison masks (PR #213925)

[David Green via llvm-commits]

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@@ -362,6 +362,13 @@ def or_to_bsp: GICombineRule <
   (apply [{ applyOrToBSP(*${root}, MRI, B, ${matchinfo}); }])
 >;
 
+def trunc_or_to_addhn : GICombineRule <
+  (defs root:$root, simplify_uaddo_matchinfo:$matchinfo),
+  (match (G_TRUNC $dst, $src):$root,
+         [{ return matchTruncOrToADDHN(*${root}, MRI, VT, ${matchinfo}); }]),
+  (apply [{ applyTruncOrToADDHN(*${root}, MRI, B, ${matchinfo}); }])
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davemgreen wrote:

.. then `(apply (G_ADDHN $src1, $src2))`

https://github.com/llvm/llvm-project/pull/213925