[php-src] PR #23966: Zend: clear the AVX bit in ECX when the OS has not enabled AVX state
| From: | iliaal | Date: | Mon, 28 Sep 2026 12:41:58 +0000 |
| Subject: | [php-src] PR #23966: Zend: clear the AVX bit in ECX when the OS has not enabled AVX state | ||
| Groups: | php.git-pulls | ||
| Request: | Send a blank email to git-pulls+get-38880@lists.php.net to get a copy of this message | ||
Pull Request: https://github.com/php/php-src/pull/23966
Author: iliaal
zend_cpu_startup() cleared the AVX bit from EDX, where bit 28 is HTT, instead of ECX, so AVX stayed
reported when XCR0 has AVX state disabled. Builds without __builtin_cpu_supports(), such as MSVC,
then let the JIT emit VEX-encoded instructions that fault on such hosts. The mask dates from
4e30ab33d84. There is no test, since it needs a host with AVX state disabled in XCR0.