diff --git a/library/stdarch/stdsimd/arch/detect/os/x86.rs b/library/stdarch/stdsimd/arch/detect/os/x86.rs
index 502dbbae9400..a616cf3d7d0f 100644
--- a/library/stdarch/stdsimd/arch/detect/os/x86.rs
+++ b/library/stdarch/stdsimd/arch/detect/os/x86.rs
@@ -116,7 +116,6 @@ fn detect_features() -> cache::Initializer {
 
         enable(proc_info_ecx, 0, Feature::sse3);
         enable(proc_info_ecx, 9, Feature::ssse3);
-        enable(proc_info_ecx, 12, Feature::fma);
         enable(proc_info_ecx, 19, Feature::sse4_1);
         enable(proc_info_ecx, 20, Feature::sse4_2);
         enable(proc_info_ecx, 23, Feature::popcnt);
@@ -189,6 +188,9 @@ fn detect_features() -> cache::Initializer {
                         enable(proc_extended_state1_eax, 3, Feature::xsaves);
                     }
 
+                    // FMA (uses 256-bit wide registers):
+                    enable(proc_info_ecx, 12, Feature::fma);
+
                     // And AVX/AVX2:
                     enable(proc_info_ecx, 28, Feature::avx);
                     enable(extended_features_ebx, 5, Feature::avx2);