[llvm] [llvm][AMDGPU] Implemented isProfitableToHoist and isFMAFasterThanFMulAndFAdd (PR #108756)

[Matt Arsenault via llvm-commits]

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@@ -1000,6 +1031,33 @@ bool AMDGPUTargetLowering::isTruncateFree(Type *Source, Type *Dest) const {
   return DestSize < SrcSize && DestSize % 32 == 0;
 }
 
+/// Check if it is profitable to hoist instruction in then/else to if.
+/// Not profitable if I and it's user can form a FMA instruction
+/// because we prefer FMSUB/FMADD.
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arsenm wrote:

Comments copied from AArch64

https://github.com/llvm/llvm-project/pull/108756