[PATCH] D140972: [flang] Add -fstack-arrays flag

[Tom Eccles via Phabricator via cfe-commits]

tblah added inline comments.


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Comment at: flang/include/flang/Tools/CLOptions.inc:159
 inline void createDefaultFIROptimizerPassPipeline(
-    mlir::PassManager &pm, llvm::OptimizationLevel optLevel = defaultOptLevel) {
+    mlir::PassManager &pm, bool stackArrays = false, llvm::OptimizationLevel optLevel = defaultOptLevel) {
   // simplify the IR
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awarzynski wrote:
> CLANG-FORMAT-ME :) Same for other long lines here.
It seems clang-format is not run on this file. I have fixed the lines changed in my patch. Should I clang-format the whole file in a separate patch?


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Comment at: flang/test/Transforms/stack-arrays.f90:3
 
+! We have to check llvm ir here to force flang to run the whole mlir pipeline
+! this is just to check that -fstack-arrays enables the stack-arrays pass so
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awarzynski wrote:
> Also, I don't quite follow this comment:
> 
> >  We have to check llvm ir here to force flang to run the whole mlir pipeline
> 
> Why is checking LLVM IR going to force Flang to run anything?
Just running `flang-new -fc1 -emit-fir` outputs the FIR before all of the transformation passes run (which is why I have to pipe the result through `fir-opt` to run the array value copy and stack arrays passes on the first line).

Outputting LLVM IR requires all of the MLIR transformation passes to be run to transform all of the higher level dialects into the LLVM dialect. Stack arrays is run as part of that same pipeline (`fir::createMLIRToLLVMPassPipeline`). I want to test that `-fstack-arrays` does cause the stack arrays pass to run as part of that pipeline, which is why I am checking the LLVM-IR.

One alternative would be to print out which passes have run and check that, but I felt this way fits more with the spirit of the other tests.


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Comment at: flang/test/Transforms/stack-arrays.f90:6
+! only check the first example
+! RUN: %flang_fc1 -emit-llvm -o - -fstack-arrays %s | FileCheck --check-prefix=CHECK-LLVM %s
+
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awarzynski wrote:
> 
Lots of other tests do not follow this convention. It would change the FileCheck comments to look like `! LLVM: array_value_copy_simple`. 

I think it is good to require `CHECK-FEATURE:` so that any mention of `FEATURE` in comments does not confuse FileCheck. Especially for a name like LLVM which is likely to be written in capitals.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D140972/new/

https://reviews.llvm.org/D140972