[X86] Use the unaligned vector typedefs for the lddqu intrinsics pointer arguments (PR20670)

[RKSimon]

Summary

Extension to rG4390c721cba09597037578100948bbc83cc41b16, similar to the vanilla load/store intrinsics, _mm_lddqu_si128/_mm256_lddqu_si256 should take an unaligned pointer, but were using the aligned m128i/m256i types which can cause alignment warnings.

The existing sse3-builtins.c and avx-builtins.c tests in llvm-project\clang\test\CodeGen\X86 should cover this.

[pengfei]

LGTM, thanks!

clang/lib/Headers/avxintrin.h

 /// \headerfile <x86intrin.h>
 ///
 /// This intrinsic corresponds to the <c> VLDDQU </c> instruction.
 ///
 /// \param __p
 ///    A pointer to a 256-bit integer vector containing integer values.
 /// \returns A 256-bit integer vector containing the moved values.
 static __inline __m256i __DEFAULT_FN_ATTRS
-_mm256_lddqu_si256(__m256i const *__p)
+_mm256_lddqu_si256(__m256i_u const *__p)
 {
   return (__m256i)__builtin_ia32_lddqu256((char const *)__p);
 }
 
 /* SIMD store ops */
 /// Stores double-precision floating point values from a 256-bit vector
 ///    of [4 x double] to a 32-byte aligned memory location pointed to by
 ///    \a __p.

clang/lib/Headers/pmmintrin.h

 /// \headerfile <x86intrin.h>
 ///
 /// This intrinsic corresponds to the <c> VLDDQU </c> instruction.
 ///
 /// \param __p
 ///    A pointer to a 128-bit integer vector containing integer values.
 /// \returns A 128-bit vector containing the moved values.
 static __inline__ __m128i __DEFAULT_FN_ATTRS
-_mm_lddqu_si128(__m128i const *__p)
+_mm_lddqu_si128(__m128i_u const *__p)
 {
   return (__m128i)__builtin_ia32_lddqu((char const *)__p);
 }
 
 /// Adds the even-indexed values and subtracts the odd-indexed values of
 ///    two 128-bit vectors of [4 x float].
 ///
 /// \headerfile <x86intrin.h>