[flang-commits] [clang] [flang] [flang][OpenMP] Add -f[no]-openmp-simd (PR #150269)

[Tom Eccles via flang-commits]

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@@ -67,6 +81,28 @@ class SimdOnlyConversionPattern : public mlir::RewritePattern {
     LLVM_DEBUG(llvm::dbgs() << "SimdOnlyPass matched OpenMP op:\n");
     LLVM_DEBUG(op->dump());
 
+    auto eraseUnlessUsedBySimd = [&](mlir::Operation *ompOp,
+                                     mlir::StringAttr name) {
+      if (auto uses =
+              mlir::SymbolTable::getSymbolUses(name, op->getParentOp())) {
+        for (auto &use : *uses)
+          if (mlir::isa<mlir::omp::SimdOp>(use.getUser()))
+            return rewriter.notifyMatchFailure(op,
+                                               "Op used by a simd construct");
+      }
+      rewriter.eraseOp(ompOp);
+      return mlir::success();
+    };
+
+    if (auto ompOp = mlir::dyn_cast<mlir::omp::PrivateClauseOp>(op))
+      return eraseUnlessUsedBySimd(ompOp, ompOp.getSymNameAttr());
+    if (auto ompOp = mlir::dyn_cast<mlir::omp::DeclareReductionOp>(op))
+      return eraseUnlessUsedBySimd(ompOp, ompOp.getSymNameAttr());
+    if (auto ompOp = mlir::dyn_cast<mlir::omp::CriticalDeclareOp>(op))
+      return eraseUnlessUsedBySimd(ompOp, ompOp.getSymNameAttr());
+    if (auto ompOp = mlir::dyn_cast<mlir::omp::DeclareMapperOp>(op))
+      return eraseUnlessUsedBySimd(ompOp, ompOp.getSymNameAttr());
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tblah wrote:

I don't think these two can be used inside of simd, so it would be cheaper to just erase them. I think it is worth special-casing this because `SymbolTable::getSymbolUses` is expensive (it walks all operations).

https://github.com/llvm/llvm-project/pull/150269