and output the dwarf line number tables. This takes the current loc info after
an instruction is assembled and saves the needed info into an object that has
vector and for each section. These objects will be used for the final patch to
build and emit the encoded dwarf line number tables. Again for now this is only
in the Mach-O streamer but at some point will move to a more generic place.
llvm-svn: 112668
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!
llvm-svn: 112664
Reserved registers are unpredictable, and are treated as always live by machine
DCE.
Allocatable registers are never reserved, and can be used for virtual registers.
Unreserved, unallocatable registers can not be used for virtual registers, but
otherwise behave like a normal allocatable register. Most targets only have
the flag register in this set.
llvm-svn: 112649
I have not been able to find a way to test each in isolation, for a few reasons:
1) The ability to look-through non-i1 BinaryOperator's requires the ability to look through non-constant
ICmps in order for it to ever trigger.
2) The ability to do LVI-powered PHI value determination only matters in cases that ProcessBranchOnPHI
can't handle. Since it already handles all the cases without other instructions in the def-use chain
between the PHI and the branch, it requires the ability to look through ICmps and/or BinaryOperators
as well.
llvm-svn: 112611
1. Allocate them in the entry block of the function to enable function-wide
re-use. The instructions to create them should be re-materializable, so
there shouldn't be additional cost compared to creating them local
to the basic blocks where they are used.
2. Collect all of the frame index references for the function and sort them
by the local offset referenced. Iterate over the sorted list to
allocate the virtual base registers. This enables creation of base
registers optimized for positive-offset access of frame references.
(Note: This may be appropriate to later be a target hook to do the
sorting in a target appropriate manner. For now it's done here for
simplicity.)
llvm-svn: 112609
any more. I plan to reimplement alloca promotion using SSAUpdater later.
It looks like Bill's URoR logic really always needs domtree, so the pass
now always asks for domtree info.
llvm-svn: 112597
two are weak, we make them thunks to a new strong function) so don't iterate
through the function list as we're modifying it.
Also add back the outermost loop which got removed during the cleanups.
llvm-svn: 112595
This actually exposed an infinite recursion bug in ComputeValueKnownInPredecessors which theoretically already existed (in JumpThreading's
handling of and/or of i1's), but never manifested before. This patch adds a tracking set to prevent this case.
llvm-svn: 112589
getMagicNumber was treating the _binary_ data it read in as a
null terminated string. This resulted in the std::string
calculating the length, and causing an assert in other code that
assumed that the length it passed was the same as the length of
the string it would get back.
llvm-svn: 112586
