[llvm] [CodeGen] Introduce MIR-level target-independent rematerialization helper (PR #177080)

[Quentin Colombet via llvm-commits]

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@@ -0,0 +1,452 @@
+//===- RematerializerTest.cpp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
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qcolombet wrote:

I only glanced at the tests so I may have missed them but I think we are missing a few edge cases:
- Empty regions
- Multiple terminators in a region
- Check that the LIS are still correct (call the verifier) after update
- Negative tests: don't touch physreg that are not ignoreable, subregister

https://github.com/llvm/llvm-project/pull/177080