[llvm] [clang] [Instcombine] use zext's nneg flag for icmp folding (PR #70845)

[Yingwei Zheng via cfe-commits]

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@@ -0,0 +1,145 @@
+; RUN: opt < %s --O3 -S | FileCheck %s
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dtcxzyw wrote:

Could you please:
1. Convert this IR into SSA form as @nikic mentioned.
2. Drop unused attributes.
3. Re-generate tests with `llvm/utils/update_test_checks.py`.


https://github.com/llvm/llvm-project/pull/70845