This patch allows target shuffles to be combined to single input immediate permute instructions - (V)PSHUFD/VPERMILPD/VPERMILPS - allowing more general pattern matching than what we current do and improves the likelihood of memory folding compared to existing patterns which tend to reuse the input in multiple arguments.
Further permute instructions (V)PSHUFLW/(V)PSHUFHW/(V)PERMQ/(V)PERMPD may be added in the future but its proven tricky to create tests cases for them so far. (V)PSHUFLW/(V)PSHUFHW is already handled quite well in combineTargetShuffle so it may be that removing some of that code may allow us to perform more of the combining in one place without duplication.
Differential Revision: http://reviews.llvm.org/D21148
llvm-svn: 273999
We currently only allow exact matches of shuffle mask patterns during target shuffle combining.
This patch relaxes this to permit SM_SentinelUndef in the combined shuffle to always be accepted as well as allowing exact matching of the SM_SentinelZero value.
I've adjusted some tests that were requiring exact shuffle masks to now include undef values.
Differential Revision: http://reviews.llvm.org/D21495
llvm-svn: 273119
Reused the ability to split constants of a type wider than the shuffle mask to work with masks generated from scalar constants transfered to xmm.
This fixes an issue preventing PSHUFB target shuffle masks decoding rematerialized scalar constants and also exposes the XOP VPPERM bug described in PR27472.
llvm-svn: 267343
This patch reorders the combining of target shuffle masks so that when a unary shuffle takes a binary shuffle as its input but only references one of its inputs it can correctly combine into a unary shuffle mask.
This is starting to encroach on the purpose of resolveTargetShuffleInputs, but I don't want to remove it until we definitely know we won't need it for full binary shuffle combining.
There is a lot more work before we can properly support binary target shuffle masks but this was an easy case to add support for.
Differential Revision: http://reviews.llvm.org/D17858
llvm-svn: 263102
Simon Pilgrim