[compiler-rt] [sanitizer_common][PowerPC64] Fix internal_clone() error handling (PR #99908)

[Vitaly Buka via llvm-commits]

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@@ -1630,13 +1630,22 @@ uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
       "sc\n\t"
 
       /* Return to parent */
+      "0:\n\t"
+      "neg %0,3\n\t"
+      "b 2f\n\t"
       "1:\n\t"
-      "mr %0, 3\n\t"
+      "mr %0,3\n\t"
+      "2:\n\t"
+
       : "=r"(res)
       : "0"(-1), "i"(EINVAL), "i"(__NR_clone), "i"(__NR_exit), "r"(__fn),
         "r"(__cstack), "r"(__flags), "r"(__arg), "r"(__ptidptr), "r"(__newtls),
         "r"(__ctidptr), "i"(FRAME_SIZE), "i"(FRAME_TOC_SAVE_OFFSET)
       : "cr0", "cr1", "memory", "ctr", "r0", "r27", "r28", "r29");
+  if ((uptr)res >= (uptr)-4095) {
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vitalybuka wrote:

I dont see `errno` stuff on other platforms.

https://github.com/llvm/llvm-project/pull/99908