[PATCH] tree-call-cdce: If !HONOR_NANS do not make code with NaNs (PR88055)

[Jeff Law]

On 4/18/19 3:23 PM, Segher Boessenkool wrote:
> If we don't HONOR_NANS we should not try to use any unordered
> comparison results.  Best case those will just be optimized away;
> realistically, they ICE.  For example, the rs6000 backend has some
> code that specifically checks we never do this.
> 
> This patch fixes it.  Bootstrapped and tested on powerpc64-linux
> {-m32,-m64}.  Is this okay for trunk?
> 
> 
> Segher
> 
> 
> 2019-04-18  Segher Boessenkool  <segher@kernel.crashing.org>
> 
> 	PR tree-optimization/88055
> 	* tree-call-cdce.c (comparison_code_if_no_nans): New function.
> 	(gen_one_condition): Use it if !HONOR_NANS.
ISTM that this should have been marked as a regression since presumably
at some point we didn't try to eliminate the call and thus wouldn't have
generated the problematic code and ICE'd.

Thus, OK for gcc-9.
jeff