Register stackification currently checks VNInfo for changes. Make that
more accurate by testing each intervening instruction for any other defs
to the same virtual register.
Patch by Jacob Gravelle
Differential Revision: https://reviews.llvm.org/D24942
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282886 91177308-0d34-0410-b5e6-96231b3b80d8
The WebAssemly spec removing the return value from store instructions, so
remove the associated optimization from LLVM.
This patch leaves the store instruction operands in place for now, so stores
now always write to "$drop"; these will be removed in a seperate patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279100 91177308-0d34-0410-b5e6-96231b3b80d8
Instead of this:
i32.const $push10=, __stack_pointer
i32.load $push11=, 0($pop10)
Emit this:
i32.const $push10=, 0
i32.load $push11=, __stack_pointer($pop10)
It's not currently clear which is better, though there's a chance the second
form may be better at overall compression. We can revisit this when we have
more data; for now it makes sense to make PEI consistent with isel.
Differential Revision: http://reviews.llvm.org/D20411
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270635 91177308-0d34-0410-b5e6-96231b3b80d8
We currently don't represent get_local and set_local explicitly; they
are just implied by virtual register use and def. This avoids a lot of
clutter, but it does complicate stackifying: get_locals read their
operands at their position in the stack evaluation order, rather than
at their parent instruction. This patch adds code to walk the stack to
determine the precise ordering, when needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269854 91177308-0d34-0410-b5e6-96231b3b80d8
Move the register stackification and coloring passes to run very late, after
PEI, tail duplication, and most other passes. This means that all code emitted
and expanded by those passes is now exposed to these passes. This also
eliminates the need for prologue/epilogue code to be manually stackified,
which significantly simplifies the code.
This does require running LiveIntervals a second time. It's useful to think
of these late passes not as late optimization passes, but as a domain-specific
compression algorithm based on knowledge of liveness information. It's used to
compress the code after all conventional optimizations are complete, which is
why it uses LiveIntervals at a phase when actual optimization passes don't
typically need it.
Differential Revision: http://reviews.llvm.org/D20075
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269012 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
MRI::eliminateFrameIndex can emit several instructions to do address
calculations; these can usually be stackified. Because instructions with
FI operands can have subsequent operands which may be expression trees,
find the top of the leftmost tree and insert the code before it, to keep
the LIFO property.
Also use stackified registers when writing back the SP value to memory
in the epilog; it's unnecessary because SP will not be used after the
epilog, and it results in better code.
Differential Revision: http://reviews.llvm.org/D18234
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263725 91177308-0d34-0410-b5e6-96231b3b80d8
Implements a mostly-conventional redzone for the userspace
stack. Because we have unsigned load/store offsets we continue to use a
local SP subtracted from the incoming SP but do not write it back to
memory.
Differential Revision: http://reviews.llvm.org/D17525
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261662 91177308-0d34-0410-b5e6-96231b3b80d8
Previously the stack pointer was only written back to memory in the
prolog. But this is wrong for dynamic allocas, for which
target-independent codegen handles SP updates after the prolog (and
possibly even in another BB). Instead update the SP global in
ADJCALLSTACKDOWN which is generated after the SP update sequence.
This will have further refinements when we add red zone support.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261579 91177308-0d34-0410-b5e6-96231b3b80d8
The stack pointer is bumped when there is a frame pointer or when there
are static-size objects, but was only getting written back when there
were static-size objects.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261453 91177308-0d34-0410-b5e6-96231b3b80d8
CopyToReg nodes don't support FrameIndex operands. Other targets select
the FI to some LEA-like instruction, but since we don't have that, we
need to insert some kind of instruction that can take an FI operand and
produces a value usable by CopyToReg (i.e. in a vreg). So insert a dummy
copy_local between Op and its FI operand. This results in a redundant
copy which we should optimize away later (maybe in the post-FI-lowering
peephole pass).
Differential Revision: http://reviews.llvm.org/D17213
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260987 91177308-0d34-0410-b5e6-96231b3b80d8
Previously the code assumed all uses of FI on loads and stores were as
addresses. This checks whether the use is the address or a value and
handles the latter case as it does for non-memory instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259306 91177308-0d34-0410-b5e6-96231b3b80d8
Add support for frame pointer use in prolog/epilog.
Supports dynamic allocas but not yet over-aligned locals.
Target-independend CG generates SP updates, but we still need to write
back the SP value to memory when necessary.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259220 91177308-0d34-0410-b5e6-96231b3b80d8
Dan Gohman
Derek Schuff