Enable x86 intrinsics when building in floating-point mode.
Support SSE as an arch value.
Use RTCD to conditionally enable existing floating-point Celt SSE code.
Call functions directly (without RTCD) when their architecture can be presumed.
Use SSE4.1 intrinsics optimized code for Silk even in floating-point mode.
We already needed these macros for gcc with optimizations disabled,
but it appears clang needs them all the time.
Thanks to Jonathan Lennox for the report.
During review of c95c9a048f, I replaced a call to
_mm_cvtepi8_epi32() with the OP_CVTEPI16_EPI32_M64() macro (note
the 16 instead of 8).
Make a separate OP_CVTEPI8_EPI32_M32() macro and use that instead.
Thaks to Wei Zhou for the report.
1. Only for fixed point on x86 platform (32bit and 64bit, uses SIMD
intrinsics up to SSE4.2)
2. Use "configure --enable-fixed-point --enable-intrinsics" to enable
optimization, default is disabled.
3. Official test cases are verified and passed.
Signed-off-by: Timothy B. Terriberry <tterribe@xiph.org>