[PATCH] D90217: [AMDGPU][GlobalISel] Fold a chain of two shift instructions with constant operands

[Jay Foad via Phabricator via llvm-commits]

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

LGTM modulo minor comment inline.



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Comment at: llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp:1577-1578
+
+  // Producing saturating unsigned left shift that exceeds scalar size will give
+  // us undefined result.
+  if (Opcode == TargetOpcode::G_USHLSAT &&
----------------
The comment could be improved. (What you wrote is also true of all the other shifts.) How about "there is no simple replacement for a saturating unsigned left shift that exceeds the scalar size"?


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https://reviews.llvm.org/D90217