[PATCH] D102774: [LoopVectorize] Add a flag to prevent reordering of FP operations with hints

[Sander de Smalen via Phabricator via llvm-commits]

sdesmalen added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:342
+    cl::desc("Allow enabling loop hints to reorder FP operations "
+             "during vectorization."));
+
----------------
Can you add to the description that this has always been the default behaviour for Clang, so it is enabled by default to avoid causing unexpected regressions for code that uses these loop hints.


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Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:8008
         NumRuntimePointerChecks > VectorizerParams::RuntimeMemoryCheckThreshold;
-    if ((ThresholdReached && !Hints.allowReordering()) ||
+    if ((ThresholdReached && !Hints.allowReordering(HintsAllowReordering)) ||
         PragmaThresholdReached) {
----------------
This looks a bit odd. How about you make this an option to LoopVectorizationLegality, so that you can just call `Hints.allowReordering()` here without passing the option?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102774/new/

https://reviews.llvm.org/D102774