Re: -Ofast/-ffast-math and SPEC 511.pov miscompilation with gcc 13.0

[Vineet Gupta <vineetg@rivosinc.com>]

On 2/2/23 15:38, Vineet Gupta wrote:
> Hi,
>
> I've noticed SPEC 2017, 511.pov failing for RV64 on bleeding edge gcc.
> This is with -Ofast -march=rv64gcv_zba_zbb_zbc_zbs.
> Problem also happens with -O3 -ffast-math (and goes away with 
> fast-math removed)
>
> I've bisected it to b7fd7fb50111 ("frange: drop endpoints to min/max 
> representable numbers for -ffinite-math-only")
> With that commit evrp is eliding a bunch of if conditions as they 
> pertain to inf (in code snippet below, it elides code corresponding to 
> lines 1401-1418 with line 1417 being elided causing the failure).
>
> I think I know the answer, but  just wanted to confirm if that is the 
> intended behavior given -Ofast / -ffast-math
>
> Thx,
> -Vineet

Apologies, mailer munged the code snippet

     New->Angle = __builtin_huge_val();
...
    switch(New->Type)
    {
...
1246:    if(Parse_Camera_Mods(New) == false)
                       EXIT
...
     }

1401:   if (New->Up != __builtin_huge_val())
             {
...
             }

1417:   if (New->Angle != __builtin_huge_val())
             {
1419:       if ((New->Type == PERSPECTIVE_CAMERA) ||
||