use a SUB instruction instead of an ADD, because -128 can be
encoded in an 8-bit signed immediate field, while +128 can't be.
This avoids the need for a 32-bit immediate field in this case.
A similar optimization applies to 64-bit adds with 0x80000000,
with the 32-bit signed immediate field.
To support this, teach tablegen how to handle 64-bit constants.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57663 91177308-0d34-0410-b5e6-96231b3b80d8
shift counts, and patterns that match dynamic shift counts
when the subtract is obscured by a truncate node.
Add DAGCombiner support for recognizing rotate patterns
when the shift counts are defined by truncate nodes.
Fix and simplify the code for commuting shld and shrd
instructions to work even when the given instruction doesn't
have a parent, and when the caller needs a new instruction.
These changes allow LLVM to use the shld, shrd, rol, and ror
instructions on x86 to replace equivalent code using two
shifts and an or in many more cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57662 91177308-0d34-0410-b5e6-96231b3b80d8
using the 'volatile' qualifier. This should not have any operational consequences
on code, because tags should always be stripped off (giving a non-volatile pointer)
before dereferencing. The new qualification is there to catch some attempts to use
tagged pointers in a context where an untagged pointer is appropriate.
Notably this approach does not catch dereferencing of tagged pointers, but helps
in separating the two concepts a bit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57641 91177308-0d34-0410-b5e6-96231b3b80d8
x86 backend. These will all be answered with "patches welcome", so
a PR doesn't help drive them along.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57630 91177308-0d34-0410-b5e6-96231b3b80d8
basically working, feel free to remove the tag. The other targets have
really basic things that break them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57628 91177308-0d34-0410-b5e6-96231b3b80d8
because it declares a std::vector<MachineMove>, and strict
concept checking requires the definition of MachineMove to be
available.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57617 91177308-0d34-0410-b5e6-96231b3b80d8
to find opportunities for store-to-load forwarding or load CSE,
in the same way that visitStore scans back to do DSE. Also, define
a new helper function for testing whether the addresses of two
memory accesses are known to have the same value, and use it in
both visitStore and visitLoad.
These two changes allow instcombine to eliminate loads in code
produced by front-ends that frequently emit obviously redundant
addressing for memory references.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57608 91177308-0d34-0410-b5e6-96231b3b80d8
the predicates by extending simple predicates to create
more complex predicates instead of duplicating the logic
for the simple predicates.
This doesn't reduce much redundancy in DAGISelEmitter.cpp's
generated source yet; that will require improvements to
DAGISelEmitter.cpp's instruction sorting, to make it more
effectively group nodes with similar predicates together.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57565 91177308-0d34-0410-b5e6-96231b3b80d8
integer type. Invalid things like 'float 42' are now rejected by the
semantic analysis in the productions not the parser. This fixes PR2733.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57560 91177308-0d34-0410-b5e6-96231b3b80d8
are due to argument passing in calls. This is significant because
it hits all immediate arguments to calls on x86-32.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57556 91177308-0d34-0410-b5e6-96231b3b80d8
1. Compute action in X86SelectSelect based on MVT instead of type.
2. Use TLI.getValueType(..) instead of MVT::getVT(..) because the former
handles pointers and the later doesn't.
3. Don't pass TLI into isTypeLegal, since it already has access to it as
an ivar.
#2 gives fast isel some minor new functionality: handling load/stores of
pointers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57552 91177308-0d34-0410-b5e6-96231b3b80d8
which makes it easy to share the compare/imm folding logic with 'setcc'.
This shaves a bunch of instructions off the common select case, which
happens a lot in llvm-gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57549 91177308-0d34-0410-b5e6-96231b3b80d8
