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[Bug tree-optimization/37101] [4.2/4.3 Regression] wrong code: tree vectorizer omits bogus movq/movlps construct
- From: "christophe at saout dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 14 Aug 2008 00:08:45 -0000
- Subject: [Bug tree-optimization/37101] [4.2/4.3 Regression] wrong code: tree vectorizer omits bogus movq/movlps construct
- References: <bug-37101-10561@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from christophe at saout dot de 2008-08-14 00:08 -------
Created an attachment (id=16068)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16068&action=view)
Remove broken alternatives using movlps for vec_concatv2di(_rex) insn
causes gcc to emit the following valid sequence instead
(which is the sequence it always produced when I tried to build a standalone
test case):
movq 56(%rsp), %rax
addq $8, %rax
movq 56(%rsp), %xmm1
movd %rax, %xmm2
punpcklqdq %xmm2, %xmm1
movdqa %xmm1, %xmm0
BTW: that last move seems redundant...
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37101