[PATCH] D23614: [PPC] Generate positive FP zero using xor insn instead of loading from constant area

[Ehsan Amiri via llvm-commits]

amehsan added a comment.

In https://reviews.llvm.org/D23614#549008, @kbarton wrote:

> We need to handle fp16 and fp80, or at least document why they are omitted.


Currently we have problems handling fp16 and fp80. Without knowing how generally we want to handle them, I prefer to exclude them here.

For this example

  define half @t1(half %x) local_unnamed_addr #0 {
  entry:
    %cmp = fadd half %x, 0.000000e+00
    ret half %cmp
  }

I am getting this output

  OUTPUT OF: llc  -mcpu=pwr8< test.ll
  
          .text
          .abiversion 2
          .file   "<stdin>"
  LLVM ERROR: Cannot select: t20: f32 = fp16_to_fp t18
    t18: i32 = fp_to_fp16 t2
      t2: f32,ch = CopyFromReg t0, Register:f32 %vreg0
        t1: f32 = Register %vreg0
  In function: t1


https://reviews.llvm.org/D23614