[PATCH] D77543: [mlir][spirv] Fix wrong Phi parent block for back-to-back loops

[Lei Zhang via Phabricator via llvm-commits]

antiagainst marked 2 inline comments as done.
antiagainst added inline comments.


================
Comment at: mlir/lib/Dialect/SPIRV/Serialization/Serializer.cpp:99
+      Operation *op = loopOp.getOperation();
+      while ((op = op->getPrevNode()) != nullptr)
+        if (Block *incomingBlock = getStructuredControlFlowOpMergeBlock(op))
----------------
mravishankar wrote:
> Just to clarify, this loop executes at most 1 iteration? If so can we avoid having a while loop? That makes it more confusing IMO
Not necessary. This actually scans all previous ops before this loop op. For example, you can have the following:

```
spv.loop { ... } // loop1
spv.Load
spv.Bla
spv.Store
spv.loop { ... } // loop2 
```

Here if loop2 has some block arguments that require phi nodes, the incoming parent block should be loop1's merge block. loop1 is multiple ops away so we need while loop here.


Repository:
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  https://reviews.llvm.org/D77543/new/

https://reviews.llvm.org/D77543