[PATCH] D136080: [flang] Add -ffp-contract option processing

Tue Oct 18 17:47:46 PDT 2022

DavidTruby added a comment.

Glad to see this flag being added to `flang-new`! As a note to self I've written some tests that should be updated once this lands that currently don't pass through the `flang-new` driver.

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Comment at: flang/test/Driver/driver-help.f90:108
 ! HELP-FC1-NEXT: Use <value> as character line width in fixed mode
+! HELP-FC1-NEXT: -ffp-contract=<value> Form fused FP ops (e.g. FMAs): fast (fuses across statements disregarding pragmas) | on (only fuses in the same statement unless dictated by pragmas) | off (never fuses) | fast-honor-pragmas (fuses across statements unless diectated by pragmas). Default is 'fast' for CUDA, 'fast-honor-pragmas' for HIP, and 'on' otherwise.
 ! HELP-FC1-NEXT: -ffree-form            Process source files in free form
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awarzynski wrote:
> Why not expose this flag in `flang-new`? (as well as `flang-new -fc1`?)
I think @awarzynski is right here, this is an option we want to expose to end users so I think the top-level driver should have it as well.

As a general rule of thumb: if a flag is in `clang` as well as `clang -cc1` it should be in `flang` as well as `flang -fc1`
In this case `-ffp-contract` is a `clang` flag as well as a `clang -cc1` flag, and so should probably be a `flang` flag as well as `flang -fc1`

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D136080/new/

https://reviews.llvm.org/D136080