[llvm] [AMDGPU] Add RewriteMFMAForm scheduling stage tests (PR #196008)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,143 @@
+; RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx90a \
+; RUN:     -amdgpu-disable-rewrite-mfma-form-sched-stage=false \
+; RUN:     < %s | FileCheck %s
+
+define amdgpu_kernel void @test_case2_case3(
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arsenm wrote:

The function name isn't enlightening. What do "case2" and "case3" refer to? This should at least comment what this is testing 

https://github.com/llvm/llvm-project/pull/196008