[PATCH] D141560: [RISCV][CodeGen] Add codegen pattern for FLI instruction in experimental zfa extension

[Jun Sha via Phabricator via llvm-commits]

joshua-arch1 added a comment.



In D141560#4198233 <https://reviews.llvm.org/D141560#4198233>, @craig.topper wrote:

> In D141560#4198220 <https://reviews.llvm.org/D141560#4198220>, @joshua-arch1 wrote:
>
>> Anyone knows how to generate FLI from C-code? If I compile the following program, I cannot get FlI. ConstantFP will be converted to Constant in DAG.
>>
>>   void foo_double64 ()
>>   {
>>     volatile double a;
>>     a = 0.0625;
>>   }
>
> You just need to use it to do some floating point arithmetic
>
>   void foo_double64 (double x)
>   {
>     volatile double a;
>     a = x + 0.0625;
>   }
>
> or return a floating point value
>
>   double foo_double64 ()
>   {
>     return 0.0625;
>   }

Is that because we cannot directly store a ConstantFP in DAG?


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