[PATCH] D145210: [Pipeline] Adjust PostOrderFunctionAttrs placement in simplification pipeline

[Changpeng Fang via Phabricator via llvm-commits]

cfang added inline comments.
Herald added a subscriber: hoy.


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Comment at: llvm/lib/Passes/PassBuilderPipelines.cpp:838
+  // functions.
+  MainCGPipeline.addPass(PostOrderFunctionAttrsPass(/*SkipNonRecursive*/ true));
 
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We found that "nofree" attribute will greatly affect the earlyCSE pass in function simplification. In our case, missing nofree essentially disabled earlyCSE which resulted in a huge performance regression (register pressure).   Other optimizations like GVN in function simplification may also be affected by function attributes.

So is it possible that we just run this pass twice?   Thanks.


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  https://reviews.llvm.org/D145210/new/

https://reviews.llvm.org/D145210