[llvm] [AArch64][GlobalISel] Don't crash when legalising vector G_SHL (PR #168848)

[Nathan Corbyn via llvm-commits]

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@@ -1033,6 +1033,34 @@ define <2 x i128> @lshr_v2i128(<2 x i128> %0, <2 x i128> %1){
     ret <2 x i128> %3
 }
 
+define <2 x i8> @pr168848() {
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cofibrant wrote:

Good idea! I'll double check we crash and do this, thanks!

https://github.com/llvm/llvm-project/pull/168848