Remove all usages of mem::uninitialized

Author: gnzlbg

coresimd/x86/avx.rs

@@ -2875,7 +2875,8 @@ pub unsafe fn _mm256_zextpd128_pd256(a: __m128d) -> __m256d {
 // This intrinsic has no corresponding instruction.
 #[stable(feature = "simd_x86", since = "1.27.0")]
 pub unsafe fn _mm256_undefined_ps() -> __m256 {
-    _mm256_set1_ps(mem::uninitialized())
+    // FIXME: this function should return MaybeUninit<__m256>
+    mem::MaybeUninit::<__m256>::uninitialized().into_inner()
 }
 
 /// Return vector of type `__m256d` with undefined elements.
@@ -2886,7 +2887,8 @@ pub unsafe fn _mm256_undefined_ps() -> __m256 {
 // This intrinsic has no corresponding instruction.
 #[stable(feature = "simd_x86", since = "1.27.0")]
 pub unsafe fn _mm256_undefined_pd() -> __m256d {
-    _mm256_set1_pd(mem::uninitialized())
+    // FIXME: this function should return MaybeUninit<__m256d>
+    mem::MaybeUninit::<__m256d>::uninitialized().into_inner()
 }
 
 /// Return vector of type __m256i with undefined elements.
@@ -2897,7 +2899,8 @@ pub unsafe fn _mm256_undefined_pd() -> __m256d {
 // This intrinsic has no corresponding instruction.
 #[stable(feature = "simd_x86", since = "1.27.0")]
 pub unsafe fn _mm256_undefined_si256() -> __m256i {
-    _mm256_set1_epi8(mem::uninitialized())
+    // FIXME: this function should return MaybeUninit<__m256i>
+    mem::MaybeUninit::<__m256i>::uninitialized().into_inner()
 }
 
 /// Set packed __m256 returned vector with the supplied values.

coresimd/x86/cpuid.rs

@@ -2,8 +2,6 @@
 
 #![cfg_attr(feature = "cargo-clippy", allow(clippy::stutter))]
 
-use mem;
-
 #[cfg(test)]
 use stdsimd_test::assert_instr;
 
@@ -53,20 +51,26 @@ pub struct CpuidResult {
 #[cfg_attr(test, assert_instr(cpuid))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
 pub unsafe fn __cpuid_count(leaf: u32, sub_leaf: u32) -> CpuidResult {
-    let mut r = mem::uninitialized::<CpuidResult>();
-    if cfg!(target_arch = "x86") {
+    let eax;
+    let ebx;
+    let ecx;
+    let edx;
+    #[cfg(target_arch = "x86")]
+    {
         asm!("cpuid"
-             : "={eax}"(r.eax), "={ebx}"(r.ebx), "={ecx}"(r.ecx), "={edx}"(r.edx)
+             : "={eax}"(eax), "={ebx}"(ebx), "={ecx}"(ecx), "={edx}"(edx)
              : "{eax}"(leaf), "{ecx}"(sub_leaf)
              : :);
-    } else {
+    }
+    #[cfg(target_arch = "x86_64")]
+    {
         // x86-64 uses %rbx as the base register, so preserve it.
         asm!("cpuid\n"
-             : "={eax}"(r.eax), "={ebx}"(r.ebx), "={ecx}"(r.ecx), "={edx}"(r.edx)
+             : "={eax}"(eax), "={ebx}"(ebx), "={ecx}"(ecx), "={edx}"(edx)
              : "{eax}"(leaf), "{ecx}"(sub_leaf)
              : "rbx" :);
     }
-    r
+    CpuidResult { eax, ebx, ecx, edx }
 }
 
 /// See [`__cpuid_count`](fn.__cpuid_count.html).

coresimd/x86/sse.rs

@@ -1952,12 +1952,8 @@ pub unsafe fn _mm_prefetch(p: *const i8, strategy: i32) {
 #[target_feature(enable = "sse")]
 #[stable(feature = "simd_x86", since = "1.27.0")]
 pub unsafe fn _mm_undefined_ps() -> __m128 {
-    __m128(
-        mem::uninitialized(),
-        mem::uninitialized(),
-        mem::uninitialized(),
-        mem::uninitialized(),
-    )
+    // FIXME: this function should return MaybeUninit<__m128>
+    mem::MaybeUninit::<__m128>::uninitialized().into_inner()
 }
 
 /// Transpose the 4x4 matrix formed by 4 rows of __m128 in place.

coresimd/x86/sse2.rs

@@ -2847,7 +2847,8 @@ pub unsafe fn _mm_castsi128_ps(a: __m128i) -> __m128 {
 #[target_feature(enable = "sse2")]
 #[stable(feature = "simd_x86", since = "1.27.0")]
 pub unsafe fn _mm_undefined_pd() -> __m128d {
-    _mm_set1_pd(mem::uninitialized())
+    // FIXME: this function should return MaybeUninit<__m128d>
+    mem::MaybeUninit::<__m128d>::uninitialized().into_inner()
 }
 
 /// Return vector of type __m128i with undefined elements.
@@ -2857,7 +2858,8 @@ pub unsafe fn _mm_undefined_pd() -> __m128d {
 #[target_feature(enable = "sse2")]
 #[stable(feature = "simd_x86", since = "1.27.0")]
 pub unsafe fn _mm_undefined_si128() -> __m128i {
-    _mm_set1_epi8(mem::uninitialized())
+    // FIXME: this function should return MaybeUninit<__m128i>
+    mem::MaybeUninit::<__m128i>::uninitialized().into_inner()
 }
 
 /// The resulting `__m128d` element is composed by the low-order values of

crates/coresimd/src/lib.rs

@@ -26,6 +26,7 @@
     stdsimd,
     staged_api,
     align_offset,
+    maybe_uninit,
     doc_cfg,
     mmx_target_feature,
     tbm_target_feature,