in the right direction. It eliminated some hacks and will unblock codegen
work. But it's far from being done. It doesn't reject illegal expressions,
e.g. (FOO - :lower16:BAR). It also doesn't work in Thumb2 mode at all.
llvm-svn: 123369
"this" pointer for any subclass of User, you could static_cast it to
User* and then reinterpret_cast that to Use* to get the end of the
operand list. This isn't a safe assumption in general, because the
static_cast might adjust the "this" pointer. Fixed by having these
OperandTraits classes take an extra template parameter, which is the
subclass of User. This is groundwork for PR889.
llvm-svn: 123235
phi nodes. It is called from MergeBlockIntoPredecessor which is
called from GVN, which claims to preserve these.
I'm skeptical that this is the actual problem behind PR8954, but
this is a stab in the right direction.
llvm-svn: 123222
Fix the TargetRegisterInfo::NoRegister places where someone preferred
typing 'TargetRegisterInfo::NoRegister' instead of typing '0'.
Note that TableGen is already emitting xx::NoRegister in xxGenRegisterNames.inc.
llvm-svn: 123140
The numbering plan is now:
0 NoRegister.
[1;2^30) Physical registers.
[2^30;2^31) Stack slots.
[2^31;2^32) Virtual registers. (With -1u and -2u used by DenseMapInfo.)
Each segment is filled from the left, so any mistaken interpretation should
quickly cause crashes.
FirstVirtualRegister has been removed. TargetRegisterInfo provides predicates
conversion functions that should be used instead of interpreting register
numbers manually.
It is now legal to pass NoRegister to isPhysicalRegister() and
isVirtualRegister(). The result is false in both cases.
It is quite rare to represent stack slots in this way, so isPhysicalRegister()
and isVirtualRegister() require that isStackSlot() be checked first if it can
possibly return true. This allows a very fast implementation of the common
predicates.
llvm-svn: 123137
void f(int* begin, int* end) { std::fill(begin, end, 0); }
which turns into a != exit expression where one pointer is
strided and (thanks to step #1) known to not overflow, and
the other is loop invariant.
The observation here is that, though the IV is strided by
4 in this case, that the IV *has* to become equal to the
end value. It cannot "miss" the end value by stepping over
it, because if it did, the strided IV expression would
eventually wrap around.
Handle this by turning A != B into "A-B != 0" where the A-B
part is known to be NUW.
llvm-svn: 123131
when no virtual registers have been allocated.
It was only used to resize IndexedMaps, so provide an IndexedMap::resize()
method such that
Map.grow(MRI.getLastVirtReg());
can be replaced with the simpler
Map.resize(MRI.getNumVirtRegs());
This works correctly when no virtuals are allocated, and it bypasses the to/from
index conversions.
llvm-svn: 123130
physical register numbers.
This makes the hack used in LiveInterval official, and lets LiveInterval be
oblivious of stack slots.
The isPhysicalRegister() and isVirtualRegister() predicates don't know about
this, so when a variable may contain a stack slot, isStackSlot() should always
be tested first.
llvm-svn: 123128
of using a Location class with the same information.
When making a copy of a MachineOperand that was already stored in a
MachineInstr, it is necessary to clear the parent pointer on the copy. Otherwise
the register use-def lists become inconsistent.
Add MachineOperand::clearParent() to do that. An alternative would be a custom
MachineOperand copy constructor that cleared ParentMI. I didn't want to do that
because of the performance impact.
llvm-svn: 123109
Print virtual registers numbered from 0 instead of the arbitrary
FirstVirtualRegister. The first virtual register is printed as %vreg0.
TRI::NoRegister is printed as %noreg.
llvm-svn: 123107
Provide MRI::getNumVirtRegs() and TRI::index2VirtReg() functions to allow
iteration over virtual registers without depending on the representation of
virtual register numbers.
llvm-svn: 123098
Add a unnamed_addr bit to global variables and functions. This will be used
to indicate that the address is not significant and therefore the constant
or function can be merged with others.
If an optimization pass can show that an address is not used, it can set this.
Examples of things that can have this set by the FE are globals created to
hold string literals and C++ constructors.
Adding unnamed_addr to a non-const global should have no effect unless
an optimization can transform that global into a constant.
Aliases are not allowed to have unnamed_addr since I couldn't figure
out any use for it.
llvm-svn: 123063
1. Take a flags argument instead of a bool. This makes
it more clear to the reader what it is used for.
2. Add a flag that says that "remapping a value not in the
map is ok".
3. Reimplement MapValue to share a bunch of code and be a lot
more efficient. For lookup failures, don't drop null values
into the map.
4. Using the new flag a bunch of code can vaporize in LinkModules
and LoopUnswitch, kill it.
No functionality change.
llvm-svn: 123058
Instead encode llvm IR level property "HasSideEffects" in an operand (shared
with IsAlignStack). Added MachineInstrs::hasUnmodeledSideEffects() to check
the operand when the instruction is an INLINEASM.
This allows memory instructions to be moved around INLINEASM instructions.
llvm-svn: 123044
Also fix an off-by-one in SelectionDAGBuilder that was preventing shuffle
vectors from being translated to EXTRACT_SUBVECTOR.
Patch by Tim Northover.
The test changes are needed to keep those spill-q tests from testing aligned
spills and restores. If the only aligned stack objects are spill slots, we
no longer realign the stack frame. Prior to this patch, an EXTRACT_SUBVECTOR
was legalized by loading from the stack, which created an aligned frame index.
Now, however, there is nothing except the spill slot in the stack frame, so
I added an aligned alloca.
llvm-svn: 122995
We were never generating any of these nodes with variable indices, and there
was one legalizer function asserting on a non-constant index. If we ever have
a need to support variable indices, we can add this back again.
llvm-svn: 122993
This pass precomputes CFG block frequency information that can be used by the
register allocator to find optimal spill code placement.
Given an interference pattern, placeSpills() will compute which basic blocks
should have the current variable enter or exit in a register, and which blocks
prefer the stack.
The algorithm is ready to consume block frequencies from profiling data, but for
now it gets by with the static estimates used for spill weights.
This is a work in progress and still not hooked up to RegAllocGreedy.
llvm-svn: 122938
My i386 llvm-gcc nightly tester found a regression for
SingleSource/Benchmarks/McGill/chomp that a bisect blamed on 122743.
That seems strange but apparently the combination of earlycse and instcombine
did something bad. Chris says he intended to remove the instcombine pass, so
let's go ahead and try that. We'll see if there are any performance losses.
llvm-svn: 122907
It forms memset and memcpy's, and will someday form popcount and
other stuff. All of this is bad when compiling the implementation
of memset, memcpy, popcount, etc.
llvm-svn: 122854
