[Mlir-commits] [mlir] [mlir] Add option to run CSE between greedy rewriter iterations (PR #193081)

[Hocky Yudhiono]

================
@@ -899,6 +901,15 @@ LogicalResult RegionPatternRewriteDriver::simplify(bool *changed) && {
           }
         },
         {&region}, iteration);
+
+    // Optionally run full CSE between iterations. If CSE changes the IR we
+    // iterate again so that patterns can fire on the deduplicated operations.
+    if (config.isCSEBetweenIterationsEnabled()) {
+      DominanceInfo domInfo(region.getParentOp());
+      bool cseChanged = false;
+      eliminateCommonSubExpressions(rewriter, domInfo, region, &cseChanged);
+      continueRewrites |= cseChanged;
+    }
----------------
hockyy wrote:

```cpp
config.setScope(scope_a);
config.isCSEBetweenIterations = true;
applyPatternsGreedily(module, config);
```

I'm not sure about this behavior, should this CSE the `module` or just the `scope_a`

https://github.com/llvm/llvm-project/pull/193081