[Libclc-dev] [PATCH 1/2] amdgcn/fmin: Explicitly check for NaNs

Matt Arsenault via Libclc-dev libclc-dev at lists.llvm.org
Thu Nov 16 23:54:13 PST 2017

> On Nov 16, 2017, at 18:06, Jan Vesely via Libclc-dev <libclc-dev at lists.llvm.org> wrote:
> On Fri, 2017-11-17 at 01:10 +0000, Arsenault, Matthew via Libclc-dev
> wrote:
>> The compiler always assumes IEEE mode is enabled for compute kernels.
>> I'm not sure if the driver respects that or not.
> right, it sets ieee_mode = 1. but that's not what OpenCL expects for
> minnum/maxnum.
> "fmin and fmax behave as defined by C99 and may not match the IEEE 754-
> 2008 definition for minNum and
> maxNum with regard to signaling NaNs. Specifically, signaling NaNs may
> behave as quiet NaNs."
> indeed, clearing the flag fixes the problem
> so what would be the correct solution here.
> 1.) change llvm to not set ieee_mode for opencl compute?
> 2.) change clover to ignore/override llvm provided ieee_mode setting (I
> assume this is passed in dispatch packet)?
> 3.) patch this in libclc? (we might have to do this for older llvm if
> 1. is the proper fix)

rocm-device-libs uses canonicalize on the inputs. I think it may only be necessary on the inputs. We also are missing optimizations to eliminate some redundant canonicalizes
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