[clang] [CIR] Upstream TernaryOp (PR #137184)

[Andy Kaylor via cfe-commits]

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@@ -254,10 +254,61 @@ class CIRLoopOpInterfaceFlattening
   }
 };
 
+class CIRTernaryOpFlattening : public mlir::OpRewritePattern<cir::TernaryOp> {
+public:
+  using OpRewritePattern<cir::TernaryOp>::OpRewritePattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(cir::TernaryOp op,
+                  mlir::PatternRewriter &rewriter) const override {
+    Location loc = op->getLoc();
+    Block *condBlock = rewriter.getInsertionBlock();
+    Block::iterator opPosition = rewriter.getInsertionPoint();
+    Block *remainingOpsBlock = rewriter.splitBlock(condBlock, opPosition);
+    llvm::SmallVector<mlir::Location, 2> locs;
+    // Ternary result is optional, make sure to populate the location only
+    // when relevant.
+    if (op->getResultTypes().size())
+      locs.push_back(loc);
+    auto *continueBlock =
----------------
andykaylor wrote:

```suggestion
    Block *continueBlock =
```

https://github.com/llvm/llvm-project/pull/137184