Just to follow up...
On 10/21/18 6:13 PM, Bill Schmidt wrote: > On 10/20/18 10:53 AM, Segher Boessenkool wrote: >> Hi! >> >> On Fri, Oct 19, 2018 at 04:27:27PM -0500, Bill Schmidt wrote: >>> The x86 intrinsic compatibility headers contain a couple of instances of >>> undefined behavior where a cast to an aligned type is used when that >>> alignment is not guaranteed by the expression to be cast from. This >>> patch fixes that problem by replacing the aligned types with unaligned >>> versions of the same type. >> How did you find these? What I'm after is, did you find all instances? > Jinsong found these by using the test cases for these header files when > incorporating the headers into Clang. I will ask him whether he scanned > for additional similar cases. Only one of the issues was found by test case. The rest were found by scanning. Thanks, Bill > >>> --- gcc/config/rs6000/xmmintrin.h (revision 265318) >>> +++ gcc/config/rs6000/xmmintrin.h (working copy) >>> @@ -85,6 +85,9 @@ >>> vector types, and their scalar components. */ >>> typedef float __m128 __attribute__ ((__vector_size__ (16), __may_alias__)); >>> >>> +/* Unaligned version of the same type. */ >>> +typedef float __m128_u __attribute__ ((__vector_size__ (16), >>> __may_alias__)); >> This is identical to __m128. Do you want aligned(1) as well? > Argh, yes. I failed to copy this correctly from Jinsong. I will re-test > before > applying. > > Thanks! > Bill > >> Okay for trunk if you want that; if not, this needs explanation (a code >> comment or similar). >> >> Thanks! >> >> >> Segher >>
