[PATCH] D127964: [DCE] Eliminate no-op atan and atan2 calls

[Rainer Orth via Phabricator via llvm-commits]

ro added a comment.

In D127964#3735654 <https://reviews.llvm.org/D127964#3735654>, @spatel wrote:

> 



> Thanks for checking. I added tests and avoided folding on these patterns:
> 4bff1037bbfc3 <https://reviews.llvm.org/rG4bff1037bbfc31d6ff588a19b41f7f7f76bdeefb>
> 7f1262a322c0 <https://reviews.llvm.org/rG7f1262a322c0d80f34964004dbd3ebec58404a5f>
>
> In the initial review, we misinterpreted the POSIX docs because the optional behavior specifier for raising errors is easily missed. If there are other cases where this patch overstepped, we should fix those too.

Unfortunately, the fix isn't complete yet: I still get a `FAIL` on Solaris/amd64 (`atan.ll.x86_64` is the Linux/x86_64 output, `atan.ll.amd64` the Solaris/amd64 one):

  --- atan.ll.x86_64	2022-08-19 23:01:10.257646000 +0200
  +++ atan.ll.amd64	2022-08-19 23:00:57.605261000 +0200
  @@ -26,22 +26,22 @@
   
   define float @callatan2_00() {
     %call = call float @atan2f(float 0.000000e+00, float 0.000000e+00)
  -  ret float 0.000000e+00
  +  ret float %call
   }
   
   define float @callatan2_n00() {
     %call = call float @atan2f(float -0.000000e+00, float 0.000000e+00)
  -  ret float -0.000000e+00
  +  ret float %call
   }
   
   define float @callatan2_0n0() {
     %call = call float @atan2f(float 0.000000e+00, float -0.000000e+00)
  -  ret float 0x400921FB60000000
  +  ret float %call
   }
   
   define float @callatan2_n0n0() {
     %call = call float @atan2f(float -0.000000e+00, float -0.000000e+00)
  -  ret float 0xC00921FB60000000
  +  ret float %call
   }
   
   define float @callatan2_x0() {


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