[llvm] [SDAG] Add missing ppc_fp128 ExpandFloatRes for sincos[pi] (PR #128514)

[Benjamin Maxwell via llvm-commits]

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@@ -49,3 +49,49 @@ define { ppc_fp128, ppc_fp128 } @test_sincospi_ppcf128(ppc_fp128 %a) {
   %result = call { ppc_fp128, ppc_fp128 } @llvm.sincospi.ppcf128(ppc_fp128 %a)
   ret { ppc_fp128, ppc_fp128 } %result
 }
+
+; FIXME: Recognise this as a tail call and omit the stack frame:
+define void @test_sincos_ppcf128_tail_call(ppc_fp128 %a, ptr noalias %out_sin, ptr noalias %out_cos) {
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MacDue wrote:

That won't result in something that could be a tail call on any target that uses the (semi)-standard GNU `sincos` function (since it'll need to emit loads after the call).

https://github.com/llvm/llvm-project/pull/128514