Commit02cd6d7

authored

gh-130317: Fix strict aliasing in PyFloat_Pack8() (#133150)

* Fix strict aliasing in PyFloat_Pack8() and PyFloat_Pack4().* Fix _testcapi.float_set_snan() on x86 (32-bit).

1 parent698c6e3 commit02cd6d7Copy full SHA for 02cd6d7

File tree

+12

-9

lines changed

+12

-9

lines changed

Lines changed: 5 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -182,8 +182,11 @@ _testcapi_float_set_snan(PyObject module, PyObject obj)`
`182`	`182`	`uint64_tv;`
`183`	`183`	`memcpy(&v,&d,8);`
`184`	`184`	`v &= ~(1ULL <<51);/* make sNaN */`
`185`		`-memcpy(&d,&v,8);`
`186`		`-returnPyFloat_FromDouble(d);`
	`185`	`+`
	`186`	`+// gh-130317: memcpy() is needed to preserve the sNaN flag on x86 (32-bit)`
	`187`	`+PyObject*res=PyFloat_FromDouble(0.0);`
	`188`	`+memcpy(&((PyFloatObject*)res)->ob_fval,&v,8);`
	`189`	`+returnres;`
`187`	`190`	`}`
`188`	`191`
`189`	`192`	`staticPyMethodDeftest_methods[]= {`

Lines changed: 7 additions & 7 deletions

Original file line number	Diff line number	Diff line change
`@@ -2197,12 +2197,10 @@ PyFloat_Pack4(double x, char *data, int le)`
`2197`	`2197`
`2198`	`2198`	`memcpy(&v,&x,8);`
`2199`	`2199`	`if ((v& (1ULL <<51))==0) {`
`2200`		`-unionfloat_val {`
`2201`		`-floatf;`
`2202`		`-uint32_tu32;`
`2203`		`- }py= (unionfloat_val)&y;`
`2204`		`-`
`2205`		`-py->u32 &= ~(1 <<22);/* make sNaN */`
	`2200`	`+uint32_tu32;`
	`2201`	`+memcpy(&u32,&y,4);`
	`2202`	`+u32 &= ~(1 <<22);/* make sNaN */`
	`2203`	`+memcpy(&y,&u32,4);`
`2206`	`2204`	`}`
`2207`	`2205`	`}`
`2208`	`2206`
`@@ -2340,7 +2338,9 @@ PyFloat_Pack8(double x, char *data, int le)`
`2340`	`2338`	`return-1;`
`2341`	`2339`	`}`
`2342`	`2340`	`else {`
`2343`		`-constunsignedchars= (unsignedchar)&x;`
	`2341`	`+unsignedcharas_bytes[8];`
	`2342`	`+memcpy(as_bytes,&x,8);`
	`2343`	`+constunsignedchar*s=as_bytes;`
`2344`	`2344`	`inti,incr=1;`
`2345`	`2345`
`2346`	`2346`	`if ((double_format==ieee_little_endian_format&& !le)`

Comments

(0)