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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/47825] SSE bitwise operations on floats work -g, fail -O3 Date: Mon, 21 Feb 2011 10:44:00 -0000 [thread overview] Message-ID: <bug-47825-4-ozcOU0dusX@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-47825-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47825 Richard Guenther <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target| |x86_64-*-* Status|RESOLVED |REOPENED Last reconfirmed| |2011.02.21 10:40:58 CC| |hjl at gcc dot gnu.org Component|c |target Resolution|INVALID | Ever Confirmed|0 |1 --- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-02-21 10:40:58 UTC --- The issue is that maskarray is initialized as array of ints but then you load it as array of floats, the scheduler re-orders those so you see a load from uninitialized stack: test_setelement: .LFB546: subq $40, %rsp .LCFI0: movaps 16(%rsp), %xmm0 movl $0, 16(%rsp) movl $0, 20(%rsp) movaps %xmm0, %xmm1 andnps .LC1(%rip), %xmm0 movl $0, 24(%rsp) movl $-1, 28(%rsp) ... what is a bit inconsistent is that for mm_load_pd we use a type that allows aliasing: /* The Intel API is flexible enough that we must allow aliasing with other vector types, and their scalar components. */ typedef long long __m128i __attribute__ ((__vector_size__ (16), __may_alias__)); typedef double __m128d __attribute__ ((__vector_size__ (16), __may_alias__)); ... /* Load two DPFP values from P. The address must be 16-byte aligned. */ extern __inline __m128d __attribute__((__gnu_inline__, __always_inline__, __artificial__)) _mm_load_pd (double const *__P) { return *(__m128d *)__P; } but for mm_load_ps we don't: /* Internal data types for implementing the intrinsics. */ typedef float __v4sf __attribute__ ((__vector_size__ (16))); ... /* Load four SPFP values from P. The address must be 16-byte aligned. */ extern __inline __m128 __attribute__((__gnu_inline__, __always_inline__, __artificial__)) _mm_load_ps (float const *__P) { return (__m128) *(__v4sf *)__P; } re-opening to investigate that. HJ, are the SSE1 intrinsics not aliasing in the Intel API? The above snippets are from trunk.
next prev parent reply other threads:[~2011-02-21 10:41 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-02-20 17:03 [Bug c/47825] New: " cck0011 at yahoo dot com 2011-02-20 17:36 ` [Bug c/47825] " rguenth at gcc dot gnu.org 2011-02-20 17:42 ` cck0011 at yahoo dot com 2011-02-20 18:08 ` rguenth at gcc dot gnu.org 2011-02-20 18:57 ` cck0011 at yahoo dot com 2011-02-21 10:44 ` rguenth at gcc dot gnu.org [this message] 2011-02-21 14:26 ` [Bug target/47825] " hjl.tools at gmail dot com 2011-02-22 1:53 ` cck0011 at yahoo dot com 2021-08-13 23:23 ` pinskia at gcc dot gnu.org
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