Currently a vector move of 0 or -1 will use different instructions depending on
the size of the vector. Using a single instruction (the 128-bit one) for both
gives more opportunity for Machine CSE to eliminate instructions.
Differential Revision: https://reviews.llvm.org/D53579
llvm-svn: 345270
Summary:
The BUILD_VECTOR node will truncate its operators to match the
type. We need to take this into account when constant folding -
we need to perform a truncation before constant folding the elements.
This is because the upper bits can change the result, depending on
the operation type (for example this is the case for min/max).
This change also adds a regression test.
Reviewers: jmolloy
Subscribers: jmolloy, llvm-commits
Differential Revision: http://reviews.llvm.org/D12697
llvm-svn: 247265
John Brawn