neovim

commit 1dde678757216b019fff7ac3b6226ab997b86a8b
parent 563a369a1b254851d84c41838a8562ad7e655fa3
Author: Famiu Haque <famiuhaque@proton.me>
Date:   Fri, 22 Mar 2024 01:43:53 +0600

refactor(misc): use MSVC compiler builtin for `xctz()`

Problem: `xctz()` uses a fallback algorithm for MSVC, even though a compiler builtin exists.

Solution: Make `xctz()` use the compiler builtin for MSVC compiler.

Diffstat:
M
src/nvim/math.c
 | 
8
++++++++

1 file changed, 8 insertions(+), 0 deletions(-)
diff --git a/src/nvim/math.c b/src/nvim/math.c
@@ -4,6 +4,10 @@
 #include <stdint.h>
 #include <string.h>
 
+#ifdef _MSC_VER
+# include <intrin.h>  // Required for _BitScanForward64
+#endif
+
 #include "nvim/math.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
@@ -52,6 +56,10 @@ int xctz(uint64_t x)
   // Use compiler builtin if possible.
 #if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 4))
   return __builtin_ctzll(x);
+#elif defined(_MSC_VER)
+  unsigned long index;
+  _BitScanForward64(&index, x);
+  return (int)index;
 #else
   int count = 0;
   // Set x's trailing zeroes to ones and zero the rest.