int x(int t) {
if (t & 256)
return -26;
return 0;
}
We generate this:
tst.w r0, #256
mvn r0, #25
it eq
moveq r0, #0
while gcc generates this:
ands r0, r0, #256
it ne
mvnne r0, #25
bx lr
Scandalous really!
During ISel time, we can look for this particular pattern. One where we have a
"MOVCC" that uses the flag off of a CMPZ that itself is comparing an AND
instruction to 0. Something like this (greatly simplified):
%r0 = ISD::AND ...
ARMISD::CMPZ %r0, 0 @ sets [CPSR]
%r0 = ARMISD::MOVCC 0, -26 @ reads [CPSR]
All we have to do is convert the "ISD::AND" into an "ARM::ANDS" that sets [CPSR]
when it's zero. The zero value will all ready be in the %r0 register and we only
need to change it if the AND wasn't zero. Easy!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112664 91177308-0d34-0410-b5e6-96231b3b80d8
all the other LDM/STM instructions. This fixes asm printer crashes when
compiling with -O0. I've changed one of the NEON tests (vst3.ll) to run
with -O0 to check this in the future.
Prior to this change VLDM/VSTM used addressing mode #5, but not really.
The offset field was used to hold a count of the number of registers being
loaded or stored, and the AM5 opcode field was expanded to specify the IA
or DB mode, instead of the standard ADD/SUB specifier. Much of the backend
was not aware of these special cases. The crashes occured when rewriting
a frameindex caused the AM5 offset field to be changed so that it did not
have a valid submode. I don't know exactly what changed to expose this now.
Maybe we've never done much with -O0 and NEON. Regardless, there's no longer
any reason to keep a count of the VLDM/VSTM registers, so we can use
addressing mode #4 and clean things up in a lot of places.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112322 91177308-0d34-0410-b5e6-96231b3b80d8
with the VST4 instructions. Until after register allocation, we want to
represent sets of adjacent registers by a single super-register. These
VST4 pseudo instructions have a single QQ or QQQQ source register operand.
They get expanded to the real VST4 instructions with 4 separate D register
operands. Once this conversion is complete, we'll be able to remove the
NEONPreAllocPass and avoid some fragile and hacky code elsewhere.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112108 91177308-0d34-0410-b5e6-96231b3b80d8
VECTOR_SHUFFLEs to REG_SEQUENCE instructions. The standard ISD::BUILD_VECTOR
node corresponds closely to REG_SEQUENCE but I couldn't use it here because
its operands do not get legalized. That is pretty awful, but I guess it
makes sense for other targets. Instead, I have added an ARM-specific version
of BUILD_VECTOR that will have its operands properly legalized.
This fixes the rest of Radar 7872877.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105439 91177308-0d34-0410-b5e6-96231b3b80d8
A temporary flag -arm-tail-calls defaults to off,
so there is no functional change by default.
Intrepid users may try this; simple cases work
but there are bugs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105413 91177308-0d34-0410-b5e6-96231b3b80d8
const_casts, and it reinforces the design of the Target classes being
immutable.
SelectionDAGISel::IsLegalToFold is now a static member function, because
PIC16 uses it in an unconventional way. There is more room for API
cleanup here.
And PIC16's AsmPrinter no longer uses TargetLowering.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101635 91177308-0d34-0410-b5e6-96231b3b80d8
These instructions are only needed for codegen, so I've removed all the
explicit encoding bits for now; they should be set in the same way as the for
VLDMD and VSTMD whenever we add encodings for VFP. The use of addrmode5
requires that the instructions be custom-selected so that the number of
registers can be set in the AM5Opc value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99309 91177308-0d34-0410-b5e6-96231b3b80d8
of D registers. Add a separate VST1q instruction with a Q register
source operand for use by storeRegToStackSlot.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99265 91177308-0d34-0410-b5e6-96231b3b80d8
of D registers. Add a separate VLD1q instruction with a Q register
destination operand for use by loadRegFromStackSlot.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99261 91177308-0d34-0410-b5e6-96231b3b80d8
with changes to add a separate optional register update argument. Change all
the NEON instructions with address register writeback to use it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99095 91177308-0d34-0410-b5e6-96231b3b80d8
load/stores with address register writeback, and use "odd" suffix to distinguish
instructions to access odd numbered registers (instead of "a" and "b").
No functional changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99066 91177308-0d34-0410-b5e6-96231b3b80d8
optional register update argument, which is currently unused -- when we add
support for that, it can just be a separate operand.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98683 91177308-0d34-0410-b5e6-96231b3b80d8
DoInstructionSelection. Inline "SelectRoot" into it from DAGISelHeader.
Sink some other stuff out of DAGISelHeader into SDISel.
Eliminate the various 'Indent' stuff from various targets, which dates
to when isel was recursive.
17 files changed, 114 insertions(+), 430 deletions(-)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97555 91177308-0d34-0410-b5e6-96231b3b80d8
