[llvm] [AMDGPU] add tests for loop definition of bitconvert (PR #133052)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,68 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+
+; RUN: llc -mtriple=amdgcn  < %s | FileCheck -check-prefix=GCN %s
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arsenm wrote:

Avoid using the default target. -mcpu=tahiti? Also extra spaces before < 

https://github.com/llvm/llvm-project/pull/133052