Prior to this change, stack realignment was achieved using the SRLI/SLLI
instructions in two steps. With this patch, stack realignment is
optimized using a single `BSTRINS` instruction.
Reviewed By: SixWeining, xen0n
Differential Revision: https://reviews.llvm.org/D158384
We set it conservatively so that it is turned on when optimization
is enabled, i.e. when the optimization level is not `O0`.
Reviewed By: xen0n
Differential Revision: https://reviews.llvm.org/D142876
With D134950, targets get notified when a virtual register is created and/or
cloned. Targets can do the needful with the delegate callback. AMDGPU propagates
the virtual register flags maintained in the target file itself. They are useful
to identify a certain type of machine operands while inserting spill stores and
reloads. Since RegAllocFast spills the physical register itself, there is no way
its virtual register can be mapped back to retrieve the flags. It can be solved
by passing the virtual register as an additional argument. This argument has no
use when the spill interfaces are called during the greedy allocator or even the
PrologEpilogInserter and can pass a null register in such cases.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D138656
When all registers have been allocated and CFR needs to be saved on the
stack, an emergency spill slot is required. Because CFR's spill and
reload require a general purpose register to transfer.
The attached test case was bugpoint-reduced down from
`MultiSource/Benchmarks/mafft/Lalignmm.c` in the test-suite.
Without this patch, llc will crash and report the following errors:
```
LLVM ERROR: Error while trying to spill R4 from class GPR: Cannot scavenge register without an emergency spill slot!
```
Reviewed By: SixWeining
Differential Revision: https://reviews.llvm.org/D138007
When the range of the unconditional branch is overflow, the indirect
branch way is used. The case when there is no scavenged register for
indirect branch needs to spill register to stack.
Reviewed By: SixWeining, wangleiat
Differential Revision: https://reviews.llvm.org/D137821
When using `llvm.returnaddress` intrinsic, special handling is required
for the spill of the `RA` register. Otherwise it will cause the verifier
fail in some cases (e.g. pr17377.c of the GCC C Torture Suite).
Specifically:
```
*** Bad machine code: Using an undefined physical register ***
- function: f
- basic block: %bb.0 entry (0xd94d18)
- instruction: ST_D killed $r1, $r22, -40 :: (store (s64) into %stack.2)
- operand 0: killed $r1
```
Reviewed By: SixWeining
Differential Revision: https://reviews.llvm.org/D137387
An emergency spill slot is created when the stack size cannot be
represented by an 11-bit signed number.
This patch also modifies how the `sp` is adjusted in the prologue.
`RegScavenger` will place the spill instruction before the prologue
if a VReg is created in the prologue. This will pollute the caller's
stack data. Therefore, until there is better way, we just use the
`addi.w/d` instruction for stack adjustment to ensure that VReg will
not be created. (RISCV has the same issue #58286)
Due to the addition of emergency spill slot, some test cases that use
exact stacksize need to be updated.
Differential Revision: https://reviews.llvm.org/D135757
This patch split the SP adjustment to reduce the instructions in
prologue and epilogue. In this way, the offset of the callee saved
register could fit in a single store.
Similar to D68011(RISCV).
Differential Revision: https://reviews.llvm.org/D136222
This patch ensures the `$fp` always points to the bottom of the vararg
spill region.
Includes support for expand `ISD::DYNAMIC_STACKALLOC`.
Differential Revision: https://reviews.llvm.org/D130250
This patch introduces basic tablegen infra such as
LoongArch{InstrFormats,InstrInfo,RegisterInfo,CallingConv,}.td.
For now, only add instruction definitions for LoongArch basic integer
operations.
Our initial target is a working MC layer rather than codegen,
so appropriate SelectionDAG patterns will come later.
Differential revision: https://reviews.llvm.org/D115861
