[llvm] [GISel][RISCV] Legalize `G_FREM` to use fmod (PR #93063)

[Matt Arsenault via llvm-commits]

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@@ -64,3 +64,67 @@ body:             |
     PseudoRET implicit $x10, implicit $x11
 
 ...
+---
+name:            frem_half_bitcast
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arsenm wrote:

Don't need the bitcast part of the name, also f16 for consistency with other functions 

https://github.com/llvm/llvm-project/pull/93063