[llvm] [InstCombine] Do not simplify lshr/shl arg if it is part of fshl rotate pattern. (PR #66115)

[Simon Pilgrim via llvm-commits]

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@@ -722,6 +722,134 @@ define i32 @fsh_orconst_rotate(i32 %a) {
   ret i32 %t2
 }
 
+define i32 @fsh_rotate_25(i8 %x, i32 %y) {
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RKSimon wrote:

+1 to indicate negative tests

Als, you can add the tests as a stacked first commit so the second commit in the patch can show the test changes

https://github.com/llvm/llvm-project/pull/66115