As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
Loosening the matcher definition reveals a subtle bug in InstSimplify (we should not
assume that because an operand constant matches that it's safe to return it as a result).
So I'm making that change here too (that diff could be independent, but I'm not sure how
to reveal it before the matcher change).
This also seems like a good reason to *not* include matchers that capture the value.
We don't want to encourage the potential misstep of propagating undef values when it's
not allowed/intended.
I didn't include the capture variant option here or in the related rL325437 (m_One),
but it already exists for other constant matchers.
llvm-svn: 325466
This is similar to the computeKnownBits improvement in rL268479.
There's probably more we can do for vector logic instructions, but
this should let us see non-splat constant masking ops that can
become vector selects instead of and/andn/or sequences.
Differential Revision: http://reviews.llvm.org/D21610
llvm-svn: 273459
Exact shifts may not shift out any non-zero bits. Use computeKnownBits
to determine when this occurs and just return the left hand side.
This fixes PR21477.
llvm-svn: 221325
This function was complicated by the fact that it tried to perform
canonicalizations that were already preformed by InstSimplify. Remove
this extra code and move the tests over to InstSimplify. Add asserts to
make sure our preconditions hold before we make any assumptions.
llvm-svn: 220314
Eric Christopher