[llvm] [DAG] Support saturated truncate (PR #99418)

[Craig Topper via llvm-commits]

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@@ -804,6 +804,9 @@ enum NodeType {
 
   /// TRUNCATE - Completely drop the high bits.
   TRUNCATE,
+  /// TRUNCATE_[SU]SAT - Truncate for saturated operand
+  TRUNCATE_SSAT,
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topperc wrote:

Is TRUNCATE_SSAT signed input to signed result?
Is TRUNCATE_USAT unsigned input to unsigned result?

I ask because X86's packuswb instructon does signed input to unsigned result so its worth being clearing here.

https://github.com/llvm/llvm-project/pull/99418