[v4,2/2] x86: Add comment explaining no Slow_SSE4_2 check in ifunc-sse4_2
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Commit Message
Just for clarities sake and so that if a future implementation is
added we remember to add the check.
---
sysdeps/x86_64/multiarch/ifunc-sse4_2.h | 4 ++++
1 file changed, 4 insertions(+)
@@ -27,6 +27,10 @@ IFUNC_SELECTOR (void)
{
const struct cpu_features* cpu_features = __get_cpu_features ();
+ /* This function uses slow sse4.2 instructions (pcmpstri) but since
+ there is no other optimized implementation keep using. If an
+ optimized fallback is added add a X86_ISA_CPU_FEATURE_ARCH_P
+ (cpu_features, Slow_SSE4_2) check. */
if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_2))
return OPTIMIZE (sse42);