[llvm] [TableGen][DecoderEmitter] Report all decoding conflicts (PR #157847)

[Rahul Joshi via llvm-commits]

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@@ -2585,7 +2598,10 @@ template <typename T> constexpr uint32_t InsnBitWidth = 0;
       //    across all decoder tables.
       //  - predicates are shared across all decoder tables.
       TableInfo.Table.clear();
-      TableBuilder.buildTable(FC, BitWidth);
+      HasConflict |= TableBuilder.buildTable(FC, BitWidth);
+      // Skip emitting table entries if a conflict has been detected.
+      if (HasConflict)
+        continue;
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jurahul wrote:

But the top-level chooser may not have the conflict, so we will need to propagate it up I think. Let me check

https://github.com/llvm/llvm-project/pull/157847