When determining if two different loads are from the same base address,
this patch allows one load to use a t2LDRi8 address mode and another to
use a t2LDRi12 address mode. The current implementation is very
conservative and this allows the case of differing Thumb2 byte loads to
be considered. Allowing these differing modes instead of forcing the exact
same opcode is useful for situations where one opcodes loads from a base
address+1 and a second opcode loads for a base address-1.
Patch by Daniel Stewart.
llvm-svn: 188385
- For whatever reason, we have a lot of test files with bogus unicode
characters. This patch allows those scripts to still be parsed on Python3 by
changing the parsing logic to work on binary files, and only require the
actual script commands to be convertible to ascii.
llvm-svn: 188376
It's useful to be able to write down floating-point numbers without having to
worry about what they'll be rounded to (as C99 discovered), this extends that
ability to the MC assembly parsers.
llvm-svn: 188370
extremely subtle miscompilations (such as a load getting replaced with
the value stored *below* the load within a basic block) related to
promoting an alloca to an SSA value, there is the dim possibility that
you hit this. Please let me know if you won this unfortunate lottery.
The first half of mem2reg's core logic (as it is used both in the
standalone mem2reg pass and in SROA) builds up a mapping from
'Instruction *' to the index of that instruction within its basic block.
This allows quickly establishing which store dominate a particular load
even for large basic blocks. We cache this information throughout the
run of mem2reg over a function in order to amortize the cost of
computing it.
This is not in and of itself a strange pattern in LLVM. However, it
introduces a very important constraint: absolutely no instruction can be
deleted from the program without updating the mapping. Otherwise a newly
allocated instruction might get the same pointer address, and then end
up with a wrong index. Yes, LLVM routinely suffers from a *single
threaded* variant of the ABA problem. Most places in LLVM don't find
avoiding this an imposition because they don't both delete and create
new instructions iteratively, but mem2reg *loves* to do this... All the
time. Fortunately, the mem2reg code was really careful about updating
this cache to handle this eventuallity... except when it comes to the
debug declare intrinsic. Oops. The fix is to invalidate that pointer in
the cache when we delete it, the same as we do when deleting alloca
instructions and other instructions.
I've also caused the same bug in new code while working on a fix to
PR16867, so this seems to be a really unfortunate pattern. Hopefully in
subsequent patches the deletion of dead instructions can be consolidated
sufficiently to make it less likely that we'll see future occurences of
this bug.
Sorry for not having a test case, but I have literally no idea how to
reliably trigger this kind of thing. It may be single-threaded, but it
remains an ABA problem. It would require a really amazing number of
stars to align.
llvm-svn: 188367
Use the pointer size if datalayout is available.
Use i64 if it's not, which is consistent with what other
places do when the pointer size is unknown.
The test doesn't really test this in a useful way
since it will be transformed to that later anyway,
but this now tests it for non-zero arrays and when
datalayout isn't available. The cases in
visitGetElementPtrInst should save an extra re-visit to
the newly created GEP since it won't need to cleanup after
itself.
llvm-svn: 188339
When computing the use set of a store, we need to add the store to the write
set prior to iterating over later instructions. Otherwise, if there is a later
aliasing load of that store, that load will not be tagged as a use, and bad
things will happen.
trackUsesOfI still adds later dependent stores of an instruction to that
instruction's write set, but it never sees the original instruction, and so
when tracking uses of a store, the store must be added to the write set by the
caller.
Fixes PR16834.
llvm-svn: 188329
However, opt -O2 doesn't run mem2reg directly so nobody noticed until r188146
when SROA started sending more things directly down the PromoteMemToReg path.
In order to revert r187191, I also revert dependent revisions r187296, r187322
and r188146. Fixes PR16867. Does not add the testcases from that PR, but both
of them should get added for both mem2reg and sroa when this revert gets
unreverted.
llvm-svn: 188327
Clients of the option parsing library should handle it explicitly
using a KIND_REMAINING_ARGS option.
Clang and lld have been updated in r188316 and r188318, respectively.
Also fix -Wsign-compare warning in the option parsing test.
llvm-svn: 188323
A common idiom is to use zero and all-ones as sentinal values and to
check for both in a single conditional ("x != 0 && x != (unsigned)-1").
That generates code, for i32, like:
testl %edi, %edi
setne %al
cmpl $-1, %edi
setne %cl
andb %al, %cl
With this transform, we generate the simpler:
incl %edi
cmpl $1, %edi
seta %al
Similar improvements for other integer sizes and on other platforms. In
general, combining the two setcc instructions into one is better.
rdar://14689217
llvm-svn: 188315
This adds KIND_REMAINING_ARGS, a class of options that consume
all remaining arguments on the command line.
This will be used to support /link in clang-cl, which is used
to forward all remaining arguments to the linker.
It also allows us to remove the hard-coded handling of "--",
allowing clients (clang and lld) to implement that functionality
themselves with this new option class.
Differential Revision: http://llvm-reviews.chandlerc.com/D1387
llvm-svn: 188314
* msa SubtargetFeature
* registers
* ld.[bhwd], and st.[bhwd] instructions
Does not correctly prohibit use of both 32-bit FPU registers and MSA together.
Patch by Daniel Sanders
llvm-svn: 188313
LowerCallTo returns a pair with the return value of the call as the first
element and the chain associated with the return value as the second element. If
we lower a call that has a void return value, LowerCallTo returns an SDValue
with a NULL SDNode and the chain for the call. Thus makeLibCall by just
returning the first value makes it impossible for you to set up the chain so
that the call is not eliminated as dead code.
I also updated all references to makeLibCall to reflect the new return type.
llvm-svn: 188300
