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
llvm-svn: 263725
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
llvm-svn: 261662
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.
llvm-svn: 261579
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.
llvm-svn: 261453
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
llvm-svn: 260987
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.
llvm-svn: 259306
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.
llvm-svn: 259220
Previously we only supported putting the FI into memory operand offset
fields if there was nothing there already. Now combine them.
Differential Revision: http://reviews.llvm.org/D15941
llvm-svn: 257084
Summary:
Implement eliminateCallFramePsuedo to handle ADJCALLSTACKUP/DOWN
pseudo-instructions. Add a test calling a vararg function which causes non-0
adjustments. This revealed an issue with RegisterCoalescer wherein it
eliminates a COPY from SP32 to a vreg but failes to update the live ranges
of EXPR_STACK, causing a machineinstr verifier failure (so this test
is commented out).
Also add a dynamic alloca test, which causes a callseq_end dag node with
a 0 (instead of undef) second argument to be generated. We currently fail to
select that, so adjust the ADJCALLSTACKUP tablegen code to handle it.
Differential Revision: http://reviews.llvm.org/D15587
llvm-svn: 255844
Summary:
Use the SP32 physical register as the base for FrameIndex
lowering. Update it and the __stack_pointer global var in the prolog and
epilog. Extend the mapping of virtual registers to wasm locals to
include the physical registers.
Rather than modify the target-independent PrologEpilogInserter (which
asserts that there are no virtual registers left) include a
slightly-modified copy for Wasm that does not have this assertion and
only clears the virtual registers if scavenging was needed (which of
course it isn't for wasm).
Differential Revision: http://reviews.llvm.org/D15344
llvm-svn: 255392
Derek Schuff