[PATCH] D25987: [DAG] Match USUBSAT patterns through zext/trunc

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:9875
+          // Look for a general sub with unsigned saturation first.
+          // zext(x) >= y ? x - trunc(y) : 0 --> usubsat x, y
+          // zext(x) >  y ? x - trunc(y) : 0 --> usubsat x, y
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x and y don't have the same bitwidth so the result of the fold isn't usubsat x, y.  Is it usubsat x, trunc(umin(y, SatLimit))?


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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D25987/new/

https://reviews.llvm.org/D25987