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

[David Green via llvm-commits]

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@@ -5375,6 +5383,10 @@ def : Pat<(v16i8 (concat_vectors
                  (v8i8 (trunc (smax (smin (v8i16 V128:$Vn), (v8i16 VImm7F)),
                                           (v8i16 VImm80)))))),
           (SQXTNv16i8 (INSERT_SUBREG (IMPLICIT_DEF), V64:$Vd, dsub), V128:$Vn)>;
+def : Pat<(v16i8 (concat_vectors
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davemgreen wrote:

There are some extra test cases in llvm/test/CodeGen/AArch64/qmovn.ll (but only for legal cases), and I added the missing patterns in cbebacef5e12c985ca32c894bcfddec9adb2fc85.

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