[llvm] Reapply "[LICM] Fold associative binary ops to promote code hoisting (#81608)" (PR #100377)

[Nikita Popov via llvm-commits]

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@@ -0,0 +1,229 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=licm < %s | FileCheck %s
+
+; Fold ADD and remove old op if unused.
+; https://alive2.llvm.org/ce/z/wAY-Nd
+define void @add_one_use(i64 %c) {
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nikic wrote:

Prefer using two different `%c1` and `%c2`, as the transform isn't limited to equal operands.

https://github.com/llvm/llvm-project/pull/100377