[llvm] [HEXAGON] [MachinePipeliner] Fix the DAG in case of dependent phis. (PR #135925)

[Ryotaro Kasuga via llvm-commits]

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@@ -5,11 +5,13 @@
 ; 2, so the computation for the number of Phis needs to be adjusted when
 ; the incoming prolog block is from prolog 0 or prolog 1.
 ; Note: the pipeliner no longer generates a 3 stage pipeline for this test.
+; Note: the pipeliner has been generating a 4-stage pipelined loop.
 
 ; CHECK: loop0
 ; CHECK: [[REG0:r([0-9]+)]] = add(r{{[0-8]+}},#8)
+; CHECK: r{{[0-9]+}} = [[REG0]]
 ; CHECK: endloop0
-; CHECK: [[REG0]] = add(r{{[0-9]+}},#8)
+; CHECK: r{{[0-9]+}} = add(r{{[0-9]+}},#8)
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kasuga-fj wrote:

Is this change correct? The purpose of this test seems to verify if the value is properly promoted to epilog blocks. If it is no longer possible to check it with this case, I think it's better to use `XFAIL` than modifying the CHECK directives to make this test pass.

https://github.com/llvm/llvm-project/pull/135925