This uses less memory and it reduces the complexity of sub-class
operations:
- hasSubClassEq() and friends become O(1) instead of O(N).
- getCommonSubClass() becomes O(N) instead of O(N^2).
In the future, TableGen will infer register classes. This makes it
cheap to add them.
llvm-svn: 140898
This PR basically reports a problem where a crash in generated code
happened due to %rbp being clobbered:
pushq %rbp
movq %rsp, %rbp
....
vmovmskps %ymm12, %ebp
....
movq %rbp, %rsp
popq %rbp
ret
Since Eric's r123367 commit, the default stack alignment for x86 32-bit
has changed to be 16-bytes. Since then, the MaxStackAlignmentHeuristicPass
hasn't been really used, but with AVX it becomes useful again, since per
ABI compliance we don't always align the stack to 256-bit, but only when
there are 256-bit incoming arguments.
ReserveFP was only used by this pass, but there's no RA target hook that
uses getReserveFP() to check for the presence of FP (since nothing was
triggering the pass to run, the uses of getReserveFP() were removed
through time without being noticed). Change this pass to use
setForceFramePointer, which is properly called by MachineFunction
hasFP method.
The testcase is very big and dependent on RA, not sure if it's worth
adding to test/CodeGen/X86.
llvm-svn: 139939
to MCRegisterInfo. Also initialize the mapping at construction time.
This patch eliminate TargetRegisterInfo from TargetAsmInfo. It's another step
towards fixing the layering violation.
llvm-svn: 135424
Some x86-32 calls pop values off the stack, and we need to readjust the
stack pointer after the call. This happens when ADJCALLSTACKUP is
eliminated.
It could happen that spill code was inserted between the CALL and
ADJCALLSTACKUP instructions, and we would compute wrong stack pointer
offsets for those frame index references.
Fix this by inserting the stack pointer adjustment immediately after the
call instead of where the ADJCALLSTACKUP instruction was erased.
I don't have a test case since we don't currently insert code in that
position. We will soon, though. I am testing a regalloc patch that
didn't work on Linux because of this.
llvm-svn: 134113
Drop the FpMov instructions, use plain COPY instead.
Drop the FpSET/GET instruction for accessing fixed stack positions.
Instead use normal COPY to/from ST registers around inline assembly, and
provide a single new FpPOP_RETVAL instruction that can access the return
value(s) from a call. This is still necessary since you cannot tell from
the CALL instruction alone if it returns anything on the FP stack. Teach
fast isel to use this.
This provides a much more robust way of handling fixed stack registers -
we can tolerate arbitrary FP stack instructions inserted around calls
and inline assembly. Live range splitting could sometimes break x87 code
by inserting spill code in unfortunate places.
As a bonus we handle floating point inline assembly correctly now.
llvm-svn: 134018
target machine from those that are only needed by codegen. The goal is to
sink the essential target description into MC layer so we can start building
MC based tools without needing to link in the entire codegen.
First step is to refactor TargetRegisterInfo. This patch added a base class
MCRegisterInfo which TargetRegisterInfo is derived from. Changed TableGen to
separate register description from the rest of the stuff.
llvm-svn: 133782
The register allocators automatically filter out reserved registers and
place the callee saved registers last in the allocation order, so custom
methods are no longer necessary just for that.
Some targets still use custom allocation orders:
ARM/Thumb: The high registers are removed from GPR in thumb mode. The
NEON allocation orders prefer to use non-VFP2 registers first.
X86: The GR8 classes omit AH-DH in x86-64 mode to avoid REX trouble.
SystemZ: Some of the allocation orders are omitting R12 aliases without
explanation. I don't understand this target well enough to fix that. It
looks like all the boilerplate could be removed by reserving the right
registers.
llvm-svn: 132781
was saying that the matching superregister class of GR32_NOREX in GR64_NOREX_NOSP
is GR64_NOREX, which drops the NOSP constraint. This fixes PR10032.
llvm-svn: 132225
The hook will be used by the register allocator when recomputing register
classes after removing constraints.
Thumb1 code doesn't allow anything larger than tGPR, and x86 needs to ensure
that the spill size doesn't change.
llvm-svn: 130228
flexible.
If it returns a register class that's different from the input, then that's the
register class used for cross-register class copies.
If it returns a register class that's the same as the input, then no cross-
register class copies are needed (normal copies would do).
If it returns null, then it's not at all possible to copy registers of the
specified register class.
llvm-svn: 127368
