From: Nikita Popov <nikita.ppv@gmail.com>
Date: Mon, 18 Mar 2019 09:12:15 +0000 (+0100)
Subject: Remove x86 bit test optimization
X-Git-Tag: php-7.3.4RC1~12
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c4464526cd8c7ef246ea4be145d798e084460d9d;p=php

Remove x86 bit test optimization

This is undefined behavior and we cannot rely on it. Additionally it
breaks builds using undefined behavior sanitizers.
---

diff --git a/Zend/zend_portability.h b/Zend/zend_portability.h
index 12e99b74d8..301032d8c3 100644
--- a/Zend/zend_portability.h
+++ b/Zend/zend_portability.h
@@ -440,12 +440,8 @@ char *alloca();
 #define MAX(a, b)  (((a)>(b))?(a):(b))
 #define MIN(a, b)  (((a)<(b))?(a):(b))
 
-/* x86 instructions BT, SHL, SHR don't require masking */
-#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) || defined(ZEND_WIN32)
-# define ZEND_BIT_TEST(bits, bit) (((bits)[(bit) / (sizeof((bits)[0])*8)] >> (bit)) & 1)
-#else
-# define ZEND_BIT_TEST(bits, bit) (((bits)[(bit) / (sizeof((bits)[0])*8)] >> ((bit) & (sizeof((bits)[0])*8-1))) & 1)
-#endif
+#define ZEND_BIT_TEST(bits, bit) \
+	(((bits)[(bit) / (sizeof((bits)[0])*8)] >> ((bit) & (sizeof((bits)[0])*8-1))) & 1)
 
 /* We always define a function, even if there's a macro or expression we could
  * alias, so that using it in contexts where we can't make function calls