[InstCombine] Fold Select with binary op - FP opcodes
Summary:
Follow up for https://reviews.llvm.org/rL339520 and https://reviews.llvm.org/rL338300
Alive:
```
%A = fcmp oeq float %x, 0.0
%B = fadd nsz float %x, %z
%C = select i1 %A, float %B, float %y
=>
%C = select i1 %A, float %z, float %y
----------
%A = fcmp oeq float %x, 0.0
%B = fadd nsz float %x, %z
%C = select %A, float %B, float %y
=>
%C = select %A, float %z, float %y
Done: 1
Optimization is correct
%A = fcmp une float %x, -0.0
%B = fadd nsz float %x, %z
%C = select i1 %A, float %y, float %B
=>
%C = select i1 %A, float %y, float %z
----------
%A = fcmp une float %x, -0.0
%B = fadd nsz float %x, %z
%C = select %A, float %y, float %B
=>
%C = select %A, float %y, float %z
Done: 1
Optimization is correct
```
Reviewers: spatel, lebedev.ri
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50714
llvm-svn: 340538