public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
* [Bug c/37340] New: wrong code for loading an sse2 register @ 2008-09-02 19:54 Emmanuel dot Thome at inria dot fr 2008-09-02 19:55 ` [Bug c/37340] " Emmanuel dot Thome at inria dot fr ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: Emmanuel dot Thome at inria dot fr @ 2008-09-02 19:54 UTC (permalink / raw) To: gcc-bugs The following code is miscompiled at -O3 with gcc 4.3.0 ; g[1] is filled with movq+movlps instead of movq+movhps. void frob(long long *t, const long long *s1, const long long *s2) { long long w_s2[2]; long long z; z = s2[0]; w_s2[0] = z & 0x1fUL; z >>= 5; w_s2[1] = z; typedef union { __v2di s; long long x[2]; } __v2di_proxy; __v2di g[4]; g[0] = (__v2di) { 0,}; g[1] = (__v2di) { w_s2[0], w_s2[1],}; // it's unused in my testcase, and makes the assembly diff more // readable. // g[2] = (__v2di) { 0,}; g[3] = g[1]; __v2di_proxy r; r.s = g[s1[0]]; t[0] = r.x[0]; t[1] = r.x[1]; } Here is the diff of the generated asm. A full testcase follows in the form of a tar file. frob: movq (%rdx), %rax pxor %xmm0, %xmm0 movdqa %xmm0, -72(%rsp) movq %rax, %rdx andl $31, %edx movq %rdx, -96(%rsp) sarq $5, %rax - movq %rax, -104(%rsp) - movq -96(%rsp), %xmm1 - movhps -104(%rsp), %xmm1 + movq %rax, -112(%rsp) + movq -112(%rsp), %xmm1 + movlps -96(%rsp), %xmm1 Notice how the shifted rax stored in -112(%rsp) goes to xmm1 with movq while it should reach the high word. Have I done anything wrong ? E. -- Summary: wrong code for loading an sse2 register Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: Emmanuel dot Thome at inria dot fr GCC build triplet: x86_64-redhat-linux GCC host triplet: x86_64-redhat-linux GCC target triplet: x86_64-redhat-linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37340 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/37340] wrong code for loading an sse2 register 2008-09-02 19:54 [Bug c/37340] New: wrong code for loading an sse2 register Emmanuel dot Thome at inria dot fr @ 2008-09-02 19:55 ` Emmanuel dot Thome at inria dot fr 2008-09-02 19:57 ` [Bug c/37340] -foptimize-register-move => " Emmanuel dot Thome at inria dot fr ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: Emmanuel dot Thome at inria dot fr @ 2008-09-02 19:55 UTC (permalink / raw) To: gcc-bugs ------- Comment #1 from Emmanuel dot Thome at inria dot fr 2008-09-02 19:53 ------- Created an attachment (id=16198) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16198&action=view) testcase -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37340 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/37340] -foptimize-register-move => wrong code for loading an sse2 register 2008-09-02 19:54 [Bug c/37340] New: wrong code for loading an sse2 register Emmanuel dot Thome at inria dot fr 2008-09-02 19:55 ` [Bug c/37340] " Emmanuel dot Thome at inria dot fr @ 2008-09-02 19:57 ` Emmanuel dot Thome at inria dot fr 2008-09-02 20:07 ` rguenth at gcc dot gnu dot org 2008-09-02 20:54 ` [Bug target/37340] " Emmanuel dot Thome at inria dot fr 3 siblings, 0 replies; 5+ messages in thread From: Emmanuel dot Thome at inria dot fr @ 2008-09-02 19:57 UTC (permalink / raw) To: gcc-bugs ------- Comment #2 from Emmanuel dot Thome at inria dot fr 2008-09-02 19:56 ------- > Here is the diff of the generated asm. One more note. The flags are, respectively: -O -O -foptimize-register-move -- Emmanuel dot Thome at inria dot fr changed: What |Removed |Added ---------------------------------------------------------------------------- Summary|wrong code for loading an |-foptimize-register-move => |sse2 register |wrong code for loading an | |sse2 register http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37340 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c/37340] -foptimize-register-move => wrong code for loading an sse2 register 2008-09-02 19:54 [Bug c/37340] New: wrong code for loading an sse2 register Emmanuel dot Thome at inria dot fr 2008-09-02 19:55 ` [Bug c/37340] " Emmanuel dot Thome at inria dot fr 2008-09-02 19:57 ` [Bug c/37340] -foptimize-register-move => " Emmanuel dot Thome at inria dot fr @ 2008-09-02 20:07 ` rguenth at gcc dot gnu dot org 2008-09-02 20:54 ` [Bug target/37340] " Emmanuel dot Thome at inria dot fr 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu dot org @ 2008-09-02 20:07 UTC (permalink / raw) To: gcc-bugs ------- Comment #3 from rguenth at gcc dot gnu dot org 2008-09-02 20:06 ------- Sounds like a dup of PR37101 which is fixed for GCC 4.3.2. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37340 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/37340] -foptimize-register-move => wrong code for loading an sse2 register 2008-09-02 19:54 [Bug c/37340] New: wrong code for loading an sse2 register Emmanuel dot Thome at inria dot fr ` (2 preceding siblings ...) 2008-09-02 20:07 ` rguenth at gcc dot gnu dot org @ 2008-09-02 20:54 ` Emmanuel dot Thome at inria dot fr 3 siblings, 0 replies; 5+ messages in thread From: Emmanuel dot Thome at inria dot fr @ 2008-09-02 20:54 UTC (permalink / raw) To: gcc-bugs ------- Comment #4 from Emmanuel dot Thome at inria dot fr 2008-09-02 20:53 ------- (In reply to comment #3) > Sounds like a dup of PR37101 which is fixed for GCC 4.3.2. indeed. Thanks. *** This bug has been marked as a duplicate of 37101 *** -- Emmanuel dot Thome at inria dot fr changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution| |DUPLICATE http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37340 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2008-09-02 20:54 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2008-09-02 19:54 [Bug c/37340] New: wrong code for loading an sse2 register Emmanuel dot Thome at inria dot fr 2008-09-02 19:55 ` [Bug c/37340] " Emmanuel dot Thome at inria dot fr 2008-09-02 19:57 ` [Bug c/37340] -foptimize-register-move => " Emmanuel dot Thome at inria dot fr 2008-09-02 20:07 ` rguenth at gcc dot gnu dot org 2008-09-02 20:54 ` [Bug target/37340] " Emmanuel dot Thome at inria dot fr
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).