[compiler-rt] Found one more delta to unbreak build for z/os (PR #82789)

[Alexander Richardson via llvm-commits]

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@@ -383,10 +383,10 @@ static __inline fp_t __compiler_rt_fmax(fp_t x, fp_t y) {
 #endif
 }
 
-#elif defined(QUAD_PRECISION) && defined(CRT_HAS_TF_MODE)
+#elif defined(QUAD_PRECISION)
+#if defined(CRT_HAS_TF_MODE) && defined(CRT_HAS_IEEE_TF)
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arichardson wrote:

So Clang and GCC disagree on the Linux ABI here? It sounds like clang should be following GCC and using 128-bit long double since that will be used for all existing Linux code?

If there is not 128-bit floating point type on sparc (at least with clang), the it sounds to me like it should not be building the *tf* files at all?

It looks like GCC uses IEEE 128-bit long double, so maybe we can just hoist the ifdefs above the `fp_lib.h` include?

https://github.com/llvm/llvm-project/pull/82789