------- Comment #1 from rguenth at gcc dot gnu dot org 2009-05-14 11:04 ------- Confirmed. That's the SMTs do not include ref-all stuff bug so DCE removes the initialization.
extern void abort (void); typedef int __m128 __attribute__((vector_size(16), may_alias)); typedef float floatA __attribute__((may_alias)); int main() { __m128 x = { 0, 0, 0, 0 }; int i; for (i = 0; i < 4; ++i) { const float xx = ((floatA*)&x)[i]; if (xx != 0.f) abort (); } return 0; } works without may_alias on __m128 for a strange reason. I'll find the patch that fixed this. -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot |dot org |org Status|UNCONFIRMED |ASSIGNED Component|c |middle-end Ever Confirmed|0 |1 Keywords| |alias, wrong-code Last reconfirmed|0000-00-00 00:00:00 |2009-05-14 11:04:20 date| | Summary|accessing aliased __m128 |[4.3 Regression] accessing |miscompiles |aliased __m128 miscompiles Target Milestone|--- |4.3.4 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40141