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[Bug target/36224] New: vec_widen_smult_{hi,lo}_v4si generates pmuludq instruction
- From: "gnu at the-meissners dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 12 May 2008 19:59:27 -0000
- Subject: [Bug target/36224] New: vec_widen_smult_{hi,lo}_v4si generates pmuludq instruction
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
The vec_widen_smult_{hi,lo}_v4si functions are incorrect, in that they generate
the pmuludq instruction, which does a 32x32->64 unsigned multiply. For
example, multiplying -13 * 15 = gives 64424509245 with the current code, when
it should give -195.
The sse5 instructions pmacsdqh and pmacsdql could do this instruction, but not
anything in the standard sse2 set.
--
Summary: vec_widen_smult_{hi,lo}_v4si generates pmuludq
instruction
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: gnu at the-meissners dot org
GCC build triplet: x86_64-unknown-linux-gnu
GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36224