[llvm] [DAGCombiner] Avoid the pre-truncate of BUILD_VECTOR sources. (PR #75792)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,89 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc -mtriple=aarch64 < %s | FileCheck %s
+
+define i32 @lower_lshr(<4 x i32> %a, <4 x i32> %b, <4 x i32> %c, <4 x i32> %d, <4 x i32> %e, <4 x i32> %f, <4 x i32> %g, <4 x i32> %h) local_unnamed_addr #0 {
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arsenm wrote:

can you pre-commit the test to show the diff? A few more vector types also wouldn't hurt 

https://github.com/llvm/llvm-project/pull/75792