Commit 6287954709 for aom

commit 6287954709850d3ec41d38915ef82cecdbc8ca64
Author: Diksha Singh <diksha.singh@ittiam.com>
Date:   Fri Jan 23 17:55:40 2026 +0530

    x86: enable SSE4.2 in x86_simd_caps

    The function x86_simd_caps() computes flags used to enable various
    SIMD variants. Although av1_get_crc32c_value() provides an SSE4.2
    variant, support for invoking it is currently disabled. This patch
    adds support for enabling SSE4.2.
    Encoder performance results averaged over all resolutions are as
    follows:

         Encoder Instruction
    cpu   Count Reduction(%)
     2        1.17
     3        1.34
     4        0.98
     5        1.21
     6        1.41

    This change is bit-exact for all presets.

    Change-Id: Ic372e4647e586ccfe81e2c75c0da7ad43e7c2921

diff --git a/aom_ports/x86.h b/aom_ports/x86.h
index 6ce163ec6c..4d00d7241c 100644
--- a/aom_ports/x86.h
+++ b/aom_ports/x86.h
@@ -179,6 +179,7 @@ static inline uint64_t xgetbv(void) {
 #define SSE3_BITS BIT(0)
 #define SSSE3_BITS BIT(9)
 #define SSE4_1_BITS BIT(19)
+#define SSE4_2_BITS BIT(20)
 // Bits 27 (OSXSAVE) & 28 (256-bit AVX)
 #define AVX_BITS (BIT(27) | BIT(28))
 #define AVX2_BITS BIT(5)
@@ -221,6 +222,7 @@ static inline int x86_simd_caps(void) {
   flags |= FEATURE_SET(reg_ecx, SSE3) ? HAS_SSE3 : 0;
   flags |= FEATURE_SET(reg_ecx, SSSE3) ? HAS_SSSE3 : 0;
   flags |= FEATURE_SET(reg_ecx, SSE4_1) ? HAS_SSE4_1 : 0;
+  flags |= FEATURE_SET(reg_ecx, SSE4_2) ? HAS_SSE4_2 : 0;

   // bits 27 (OSXSAVE) & 28 (256-bit AVX)
   if (FEATURE_SET(reg_ecx, AVX)) {