[glibc/release/2.37/master] x86: fix wmemset ifunc stray '!' (bug 33542)

[Sam James]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ba7c1682eae563b49baeaebcd0f39538e029c4bb

commit ba7c1682eae563b49baeaebcd0f39538e029c4bb
Author: Jiamei Xie <xiejiamei@hygon.cn>
Date:   Tue Oct 14 20:14:11 2025 +0800

    x86: fix wmemset ifunc stray '!' (bug 33542)
    
    The ifunc selector for wmemset had a stray '!' in the
    X86_ISA_CPU_FEATURES_ARCH_P(...) check:
    
      if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX2)
          && X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
                                          AVX_Fast_Unaligned_Load, !))
    
    This effectively negated the predicate and caused the AVX2/AVX512
    paths to be skipped, making the dispatcher fall back to the SSE2
    implementation even on CPUs where AVX2/AVX512 are available. The
    regression leads to noticeable throughput loss for wmemset.
    
    Remove the stray '!' so the AVX_Fast_Unaligned_Load capability is
    tested as intended and the correct AVX2/EVEX variants are selected.
    
    Impact:
    - On AVX2/AVX512-capable x86_64, wmemset no longer incorrectly
      falls back to SSE2; perf now shows __wmemset_evex/avx2 variants.
    
    Testing:
    - benchtests/bench-wmemset shows improved bandwidth across sizes.
    - perf confirm the selected symbol is no longer SSE2.
    
    Signed-off-by: xiejiamei <xiejiamei@hygon.com>
    Signed-off-by: Li jing <lijing@hygon.cn>
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
    (cherry picked from commit 4d86b6cdd8132e0410347e07262239750f86dfb4)

Diff:
---
 sysdeps/x86_64/multiarch/ifunc-wmemset.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sysdeps/x86_64/multiarch/ifunc-wmemset.h b/sysdeps/x86_64/multiarch/ifunc-wmemset.h
index 1fbbd3d68e..7f68fabfc8 100644
--- a/sysdeps/x86_64/multiarch/ifunc-wmemset.h
+++ b/sysdeps/x86_64/multiarch/ifunc-wmemset.h
@@ -35,7 +35,7 @@ IFUNC_SELECTOR (void)
 
   if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX2)
       && X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
-				      AVX_Fast_Unaligned_Load, !))
+				      AVX_Fast_Unaligned_Load,))
     {
       if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512VL))
 	{