[libc-commits] [libc] [libc][stdfix] Implement fxdivi functions (rdivi) (PR #154914)

[via libc-commits]

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@@ -246,13 +248,21 @@ template <typename XType> LIBC_INLINE constexpr XType divi(int n, int d) {
   }
   bool result_is_negative = ((n < 0) != (d < 0));
 
-  unsigned int nv = static_cast<unsigned int>(n < 0 ? -n : n);
-  unsigned int dv = static_cast<unsigned int>(d < 0 ? -d : d);
-  unsigned int clz = cpp::countl_zero<unsigned int>(dv) - 1;
-  unsigned long int scaled_val = dv << clz;
+  int64_t n64 = static_cast<int64_t>(n);
+  int64_t d64 = static_cast<int64_t>(d);
+
+  uint64_t nv = static_cast<uint64_t>(n64 < 0 ? -n64 : n64);
+  uint64_t dv = static_cast<uint64_t>(d64 < 0 ? -d64 : d64);
+
+  if (d == INT_MIN) {
+    dv = dv - 1; // Two's complement
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lntue wrote:

`INT_MIN` is a power of 2.  It might be better / more accurate to multiply `nv` by 2 and divide `dv` by 2 here:
```
  // d = -2^31, dv = 2^31.  Scale-by-2 to prevent clz overflowed.
  nv <<= 1;
  dv >>= 1;
```

https://github.com/llvm/llvm-project/pull/154914