x86/SSE: incorrect code generated for <8xi8> to <8xfloat> conversion with sitofp

[llvmbot]

Bugzilla Link	11194
Resolution	FIXED
Resolved on	Oct 21, 2011 12:37
Version	trunk
OS	All
Attachments	bitcode, test driver
Reporter	LLVM Bugzilla Contributor

Extended Description

The attached test program generates an <8xi8> vector with values <1,2,3,4,5,6,7,8>, bitcasts it to an i64, shifts it and then sets the low 8 bits to be 0xff, bitcasts that back to an <8xi8> before doing a sitofp conversion to an <8xfloat> vector. The result of all this should be -1.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0. With top of tree, I'm seeing:

% llc -filetype=obj bug.ll -o bug.o && clang bug.cpp bug.o && ./a.out
-1.0 257.0 514.0 771.0 1028.0 1285.0 1542.0 1799.0
%

This bug was introduced in r142152. (It may also be related to http://llvm.org/bugs/show_bug.cgi?id=11193, but I'm filing it as a separate bug for now.)

Author: Nadav Rotem nadav.rotem@intel.com
Date: Sun Oct 16 20:31:33 2011 +0000

Enable element promotion type legalization by deafault.
Changed tests which assumed that vectors are legalized by widening them.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142152 91177308-0d34-0410-b5e6-96231b3b80d8

[llvmbot]

I can reproduce this locally. When disabling element promotion I get the expected result. Without it on ToT I get:

-1.0 257.0 514.0 771.0 1028.0 1285.0 1542.0 1799.0

[llvmbot]

Fixed in r142660. Keep 'em coming.