Check non-zero in is_power_of_two()

nikic · nikic · commit 3690a805c150 · 2020-07-30T10:17:37.000+02:00
And assert non-zero in floor_log2().

Fixes DASM_S_RANGE_I in ext/simplexml/tests/021.phpt.
diff --git a/ext/opcache/jit/zend_jit_x86.dasc b/ext/opcache/jit/zend_jit_x86.dasc
@@ -1613,6 +1613,7 @@ static uint32_t ones32(uint32_t x)
 
 static uint32_t floor_log2(uint32_t x)
 {
+	ZEND_ASSERT(x != 0);
 	x |= (x >> 1);
 	x |= (x >> 2);
 	x |= (x >> 4);
@@ -1623,7 +1624,7 @@ static uint32_t floor_log2(uint32_t x)
 
 static zend_bool is_power_of_two(uint32_t x)
 {
-	return !(x & (x - 1));
+	return !(x & (x - 1)) && x != 0;
 }
 
 static zend_bool has_concrete_type(uint32_t value_type)

Original file line number	Diff line number	Diff line change
`@@ -1613,6 +1613,7 @@ static uint32_t ones32(uint32_t x)`
`1613`	`1613`
`1614`	`1614`	`static uint32_t floor_log2(uint32_t x)`
`1615`	`1615`	`{`
	`1616`	`+ ZEND_ASSERT(x != 0);`
`1616`	`1617`	`x \|= (x >> 1);`
`1617`	`1618`	`x \|= (x >> 2);`
`1618`	`1619`	`x \|= (x >> 4);`
`@@ -1623,7 +1624,7 @@ static uint32_t floor_log2(uint32_t x)`
`1623`	`1624`
`1624`	`1625`	`static zend_bool is_power_of_two(uint32_t x)`
`1625`	`1626`	`{`
`1626`		`- return !(x & (x - 1));`
	`1627`	`+ return !(x & (x - 1)) && x != 0;`
`1627`	`1628`	`}`
`1628`	`1629`
`1629`	`1630`	`static zend_bool has_concrete_type(uint32_t value_type)`