Under normal circumstances we prefer the higher performance MOVD to extract the 0'th element of a v8i16 vector instead of PEXTRW.
But as detailed on PR27265, this prevents the SSE41 implementation of PEXTRW from folding the store of the 0'th element. Additionally it prevents us from making use of the fact that the (SSE2) reg-reg version of PEXTRW implicitly zero-extends the i16 element to the i32/i64 destination register.
This patch only preferentially lowers to MOVD if we will not be zero-extending the extracted i16, nor prevent a store from being folded (on SSSE41).
Fix for PR27265.
Differential Revision: https://reviews.llvm.org/D22509
llvm-svn: 276289
An identity COPY like this:
%AL = COPY %AL, %EAX<imp-def>
has no semantic effect, but encodes liveness information: Further users
of %EAX only depend on this instruction even though it does not define
the full register.
Replace the COPY with a KILL instruction in those cases to maintain this
liveness information. (This reverts a small part of r238588 but this
time adds a comment explaining why a KILL instruction is useful).
llvm-svn: 274952
The script now replace '.LCPI888_8' style asm symbols with the {{\.LCPI.*}} re pattern - this helps stop hardcoded symbols in 32-bit x86 tests changing with every edit of the file
Refreshed some tests to demonstrate the new check
llvm-svn: 272488
Better handling of the annoying pshuflw/pshufhw ops which only shuffle lower/upper halves of a vector.
Added vXi16 unary shuffle support for cases where i16 elements (from the same half of the source) are being splatted to the whole of one of the halves. This avoids the general lowering case which must shuffle the 32-bit elements first - meaning that we used to end up with unnecessary duplicate pshuflw/pshufhw shuffles.
Note this has the side effect of a lot of SSSE3 test cases no longer needing to use PSHUFB, as it falls below the 3 op combine threshold for when PSHUFB is typically worth it. I've raised PR26183 to discuss if the threshold should be changed and whether we need to make it more specific to the target CPU.
Differential Revision: http://reviews.llvm.org/D14901
llvm-svn: 258440
autogenerated.
Also update existing test cases which appear to be generated by it and
weren't modified (other than addition of the header) by rerunning it.
llvm-svn: 253917
The XOP shifts just have logical/arithmetic versions and the left/right shifts are controlled by whether the value is positive/negative. Because of this I've added new X86ISD nodes instead of trying to force them to use the existing shift nodes.
Additionally Excavator cores (bdver4) support XOP and AVX2 - meaning that it should use the AVX2 shifts when it can and fall back to XOP in other cases.
Differential Revision: http://reviews.llvm.org/D8690
llvm-svn: 248878
This patch improves the 32-bit target i64 constant matching to detect the shuffle vector splats that are introduced by i64 vector shift vectorization (D8416).
Differential Revision: http://reviews.llvm.org/D11327
llvm-svn: 243577
Simon Pilgrim