jlebar added a comment.
Thank you for the review, Art!
================
Comment at: include/clang/Driver/Options.td:385
@@ -384,1 +384,3 @@
HelpText<"CUDA installation path">;
+def cuda_flush_denormals_to_zero : Flag<["--"],
"cuda-flush-denormals-to-zero">,
+ HelpText<"Flush denormal floating point values to zero in CUDA device
mode.">;
----------------
tra wrote:
> We need a provide a way to both enable and disable this. We either need a
> "-no" variant or make it an option with value.
>
> Also, can we shorten it to --cuda-ftz? I would probably mistype current name
> more often than not.
>
> We need a provide a way to both enable and disable this. We either need a
> "-no" variant or make it an option with value.
Many (most) of the -f flags don't have -fno variants -- how do we decide which
ones get an -fno and which don't?
> Also, can we shorten it to --cuda-ftz? I would probably mistype current name
> more often than not.
Well, you and I both were calling it "ctz" about 50% of the time, so I'm not
sure --cuda-ftz would solve the problem! :) (In all seriousness, that was one
of the reasons I chose not to abbreviate it.)
Maybe "ftz" is a well-known acronym. Doesn't quite look like it from googling,
though.
I looked through the flags and concluded that "ftz" was more abbreviated than
most of them. Although "flush-denormals-to-zero" is at the verbose end of the
spectrum. I considered "flush-denormals", thought that was a big ambiguous --
flush them how?
================
Comment at: include/clang/Driver/Options.td:386
@@ -385,1 +385,3 @@
+def cuda_flush_denormals_to_zero : Flag<["--"],
"cuda-flush-denormals-to-zero">,
+ HelpText<"Flush denormal floating point values to zero in CUDA device
mode.">;
def dA : Flag<["-"], "dA">, Group<d_Group>;
----------------
tra wrote:
> Is there an equivalent for ftz fo host-side FP operations? It would be good
> to keep identical host and device side calculations as close as we can.
> Is there an equivalent for ftz fo host-side FP operations?
Not that I can tell. The only other one I saw was opencl's equivalent flag,
which does nothing at the moment.
================
Comment at: lib/Driver/ToolChains.cpp:4212
@@ +4211,3 @@
+ if (DriverArgs.hasArg(options::OPT_cuda_flush_denormals_to_zero))
+ CC1Args.push_back("-fcuda-flush-denormals-to-zero");
+
----------------
tra wrote:
> Perhaps we don't need different flags at driver and CC1 levels. Top-level
> "-f*" options in OPT_f_group are passed to CC1 automatically.
Aha, much better, thank you!
http://reviews.llvm.org/D18671
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