From 633c807a08e8499eb3a3c0727fdc9e4d4bec7234 Mon Sep 17 00:00:00 2001
From: Guillaume Piolat <contact@auburnsounds.com>
Date: Fri, 19 Jun 2026 19:28:37 +0200
Subject: [PATCH] nu_bsf was returning a wrong value in the LDC path.

Explanation: The 'llvm.cttz' intrinsic counts the trailing (least significant) zeros in a variable.
This number of zeroes is already the index of the first least significant set bit.
Since nu_bsf(0) is UB, no edge case.
---
 source/numem/core/math.d | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/numem/core/math.d b/source/numem/core/math.d
index bd7394a..3c74f58 100644
--- a/source/numem/core/math.d
+++ b/source/numem/core/math.d
@@ -132,7 +132,7 @@ T nu_bsf(T)(T value) @nogc nothrow @trusted pure
 if (__traits(isIntegral, T)) {
     version(LDC) {
         import ldc.intrinsics : llvm_cttz;
-        return cast(int)(value.sizeof * 8 - 1 - llvm_cttz(value, true));
+        return cast(int)(llvm_cttz(value, true));
     } else {
         
         // Slow software implementation.