subsequent changes are easier to review. About to fix some layering
issues, and wanted to separate out the necessary churn.
Also comment and sink the include of "Windows.h" in three .inc files to
match the usage in Memory.inc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198685 91177308-0d34-0410-b5e6-96231b3b80d8
This moves the check up into the parent class so that all targets can use it
without having to copy (and keep in sync) the same error message.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198579 91177308-0d34-0410-b5e6-96231b3b80d8
__builtin_returnaddress requires that the value passed into is be a constant.
However, at -O0 even a constant expression may not be converted to a constant.
Emit an error message intead of crashing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198531 91177308-0d34-0410-b5e6-96231b3b80d8
Before this patch any program that wanted to know the final symbol name of a
GlobalValue had to link with Target.
This patch implements a compromise solution where the mangler uses DataLayout.
This way, any tool that already links with Target (llc, clang) gets the exact
behavior as before and new IR files can be mangled without linking with Target.
With this patch the mangler is constructed with just a DataLayout and DataLayout
is extended to include the information the Mangler needs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198438 91177308-0d34-0410-b5e6-96231b3b80d8
This matches the data in clang which was added by Jakob Stoklund Olesen in
r179596.
Thanks for erikjv on irc for pointing me to the relevant documents:
http://sparc.com/standards/64.psabi.1.35.ps.Z
page 25: Every stack frame must be 16-byte aligned.
http://sparc.com/standards/psABI3rd.pdf
page 3-10: Although the architecture requires only word alignment, software convention and the operating system require every stack frame to be doubleword aligned.
I tried to add a test, but it looks like sparc doesn't implement dynamic stack
realignment. This will be tested in clang shortly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197646 91177308-0d34-0410-b5e6-96231b3b80d8
I think, in principle, intrinsics_gen may be added explicitly.
That said, it can be added incidentally, since each target already has dependencies to llvm-tblgen.
Almost all source files depend on both CommonTaleGen and intrinsics_gen.
Explicit add_dependencies() have been pruned under lib/Target.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195929 91177308-0d34-0410-b5e6-96231b3b80d8
add_public_tablegen_target adds *CommonTableGen to LLVM_COMMON_DEPENDS.
LLVM_COMMON_DEPENDS affects add_llvm_library (and other add_target stuff) within its scope.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195927 91177308-0d34-0410-b5e6-96231b3b80d8
This patch removes most of the trivial cases of weak vtables by pinning them to
a single object file. The memory leaks in this version have been fixed. Thanks
Alexey for pointing them out.
Differential Revision: http://llvm-reviews.chandlerc.com/D2068
Reviewed by Andy
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195064 91177308-0d34-0410-b5e6-96231b3b80d8
This change is incorrect. If you delete virtual destructor of both a base class
and a subclass, then the following code:
Base *foo = new Child();
delete foo;
will not cause the destructor for members of Child class. As a result, I observe
plently of memory leaks. Notable examples I investigated are:
ObjectBuffer and ObjectBufferStream, AttributeImpl and StringSAttributeImpl.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194997 91177308-0d34-0410-b5e6-96231b3b80d8
No new testcases. However, this patch makes all supported JIT testcases in
test/ExecutionEngine pass on Sparc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192176 91177308-0d34-0410-b5e6-96231b3b80d8
This is required because i64 is a legal type but addxcc/subxcc reads icc carry bit, which are 32 bit conditional codes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192054 91177308-0d34-0410-b5e6-96231b3b80d8
Previously, the DAGISel function WalkChainUsers was spotting that it
had entered already-selected territory by whether a node was a
MachineNode (amongst other things). Since it's fairly common practice
to insert MachineNodes during ISelLowering, this was not the correct
check.
Looking around, it seems that other nodes get their NodeId set to -1
upon selection, so this makes sure the same thing happens to all
MachineNodes and uses that characteristic to determine whether we
should stop looking for a loop during selection.
This should fix PR15840.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191165 91177308-0d34-0410-b5e6-96231b3b80d8
In sparc, setjmp stores only the registers %fp, %sp, %i7 and %o7. longjmp restores
the stack, and the callee-saved registers (all local/in registers: %i0-%i7, %l0-%l7)
using the stored %fp and register windows. However, this does not guarantee that the longjmp
will restore the registers, as they were when the setjmp was called. This is because these
registers may be clobbered after returning from setjmp, but before calling longjmp.
This patch prevents the registers %i0-%i5, %l0-l7 to live across the setjmp call using the register mask.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190033 91177308-0d34-0410-b5e6-96231b3b80d8
This field specifies registers that are preserved across function calls,
but that should not be included in the generates SaveList array.
This can be used ot generate regmasks for architectures that save
registers through other means, like SPARC's register windows.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189084 91177308-0d34-0410-b5e6-96231b3b80d8
Without explicit dependencies, both per-file action and in-CommonTableGen action could run in parallel.
It races to emit *.inc files simultaneously.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187780 91177308-0d34-0410-b5e6-96231b3b80d8
Frame index handling is now target-agnostic, so delete the target hooks
for creation & asm printing of target-specific addressing in DBG_VALUEs
and any related functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184067 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes PR16146: gdb.base__call-ar-st.exp fails after
pre-RA-sched=source fixes.
Patch by Xiaoyi Guo!
This also fixes an unsupported dbg.value test case. Codegen was
previously incorrect but the test was passing by luck.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182885 91177308-0d34-0410-b5e6-96231b3b80d8
Change SelectionDAG::getXXXNode() interfaces as well as call sites of
these functions to pass in SDLoc instead of DebugLoc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182703 91177308-0d34-0410-b5e6-96231b3b80d8
Also clean up the arguments to all the MOVCC instructions so the
operands always are (true-val, false-val, cond-code).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182221 91177308-0d34-0410-b5e6-96231b3b80d8
It was just a less powerful and more confusing version of
MCCFIInstruction. A side effect is that, since MCCFIInstruction uses
dwarf register numbers, calls to getDwarfRegNum are pushed out, which
should allow further simplifications.
I left the MachineModuleInfo::addFrameMove interface unchanged since
this patch was already fairly big.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181680 91177308-0d34-0410-b5e6-96231b3b80d8
With a little help from the frontend, it looks like the standard va_*
intrinsics can do the job.
Also clean up an old bitcast hack in LowerVAARG that dealt with
unaligned double loads. Load SDNodes can specify an alignment now.
Still missing: Calling varargs functions with float arguments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179961 91177308-0d34-0410-b5e6-96231b3b80d8
This is the default model for non-PIC 64-bit code. It supports
text+data+bss linked anywhere in the low 16 TB of the address space.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179473 91177308-0d34-0410-b5e6-96231b3b80d8
64-bit code models need multiple relocations that can't be inferred from
the opcode like they can in 32-bit code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179472 91177308-0d34-0410-b5e6-96231b3b80d8
SDNodes and MachineOperands get target flags representing the %hi() and
%lo() assembly annotations that eventually become relocations.
Also define flags to be used by the 64-bit code models.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179468 91177308-0d34-0410-b5e6-96231b3b80d8
Currently, only abs32 and pic32 are implemented. Add a test case for
abs32 with 64-bit code. 64-bit PIC code is currently broken.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179463 91177308-0d34-0410-b5e6-96231b3b80d8
The save area is twice as big and there is no struct return slot. The
stack pointer is always 16-byte aligned (after adding the bias).
Also eliminate the stack adjustment instructions around calls when the
function has a reserved stack frame.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179083 91177308-0d34-0410-b5e6-96231b3b80d8
Integer return values are sign or zero extended by the callee, and
structs up to 32 bytes in size can be returned in registers.
The CC_Sparc64 CallingConv definition is shared between
LowerFormalArguments_64 and LowerReturn_64. Function arguments and
return values are passed in the same registers.
The inreg flag is also used for return values. This is required to handle
C functions returning structs containing floats and ints:
struct ifp {
int i;
float f;
};
struct ifp f(void);
LLVM IR:
define inreg { i32, float } @f() {
...
ret { i32, float } %retval
}
The ABI requires that %retval.i is returned in the high bits of %i0
while %retval.f goes in %f1.
Without the inreg return value attribute, %retval.i would go in %i0 and
%retval.f would go in %f3 which is a more efficient way of returning
%multiple values, but it is not ABI compliant for returning C structs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178966 91177308-0d34-0410-b5e6-96231b3b80d8
64-bit SPARC v9 processes use biased stack and frame pointers, so the
current function's stack frame is located at %sp+BIAS .. %fp+BIAS where
BIAS = 2047.
This makes more local variables directly accessible via [%fp+simm13]
addressing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178965 91177308-0d34-0410-b5e6-96231b3b80d8
All arguments are formally assigned to stack positions and then promoted
to floating point and integer registers. Since there are more floating
point registers than integer registers, this can cause situations where
floating point arguments are assigned to registers after integer
arguments that where assigned to the stack.
Use the inreg flag to indicate 32-bit fragments of structs containing
both float and int members.
The three-way shadowing between stack, integer, and floating point
registers requires custom argument lowering. The good news is that
return values are passed in the exact same way, and we can share the
code.
Still missing:
- Update LowerReturn to handle structs returned in registers.
- LowerCall.
- Variadic functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178958 91177308-0d34-0410-b5e6-96231b3b80d8
This requires v9 cmov instructions using the %xcc flags instead of the
%icc flags.
Still missing:
- Select floats on %xcc flags.
- Select i64 on %fcc flags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178737 91177308-0d34-0410-b5e6-96231b3b80d8
The same compare instruction is used for 32-bit and 64-bit compares. It
sets two different sets of flags: icc and xcc.
This patch adds a conditional branch instruction using the xcc flags for
64-bit compares.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178621 91177308-0d34-0410-b5e6-96231b3b80d8
SPARC v9 extends all ALU instructions to 64 bits, so we simply need to
add patterns to use them for both i32 and i64 values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178527 91177308-0d34-0410-b5e6-96231b3b80d8
The last resort pattern produces 6 instructions, and there are still
opportunities for materializing some immediates in fewer instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178526 91177308-0d34-0410-b5e6-96231b3b80d8
SPARC v9 defines new 64-bit shift instructions. The 32-bit shift right
instructions are still usable as zero and sign extensions.
This adds new F3_Sr and F3_Si instruction formats that probably should
be used for the 32-bit shifts as well. They don't really encode an
simm13 field.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178525 91177308-0d34-0410-b5e6-96231b3b80d8
The 'sparc' architecture produces 32-bit code while 'sparcv9' produces
64-bit code.
It is also possible to run 32-bit code using SPARC v9 instructions with:
llc -march=sparc -mattr=+v9
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178524 91177308-0d34-0410-b5e6-96231b3b80d8
This is far from complete, but it is enough to make it possible to write
test cases using i64 arguments.
Missing features:
- Floating point arguments.
- Receiving arguments on the stack.
- Calls.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178523 91177308-0d34-0410-b5e6-96231b3b80d8
We are going to use the same registers for 32-bit and 64-bit values, but
in two different register classes. The I64Regs register class has a
larger spill size and alignment.
The addition of an i64 register class confuses TableGen's type
inference, so it is necessary to clarify the type of some immediates and
the G0 register.
In 64-bit mode, pointers are i64 and should use the I64Regs register
class. Implement getPointerRegClass() to dynamically provide the pointer
register class depending on the subtarget. Use ptr_rc and iPTR for
memory operands.
Finally, add the i64 type to the IntRegs register class. This register
class is not used to hold i64 values, I64Regs is for that. The type is
required to appease TableGen's type checking in output patterns like this:
def : Pat<(add i64:$a, i64:$b), (ADDrr $a, $b)>;
SPARC v9 uses the same ADDrr instruction for i32 and i64 additions, and
TableGen doesn't know to check the type of register sub-classes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178522 91177308-0d34-0410-b5e6-96231b3b80d8
Also update the documentation since Sparc is the nicest backend, and
used as an example in WritingAnLLVMBackend.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177835 91177308-0d34-0410-b5e6-96231b3b80d8
The SelectionDAG graph has MVT type labels, not register classes, so
this makes it clearer what is happening.
This notation is also robust against adding more types to the IntRegs
register class.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177829 91177308-0d34-0410-b5e6-96231b3b80d8
Add the current PEI register scavenger as a parameter to the
processFunctionBeforeFrameFinalized callback.
This change is necessary in order to allow the PowerPC target code to
set the register scavenger frame index after the save-area offset
adjustments performed by processFunctionBeforeFrameFinalized. Only
after these adjustments have been made is it possible to estimate
the size of the stack frame.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177108 91177308-0d34-0410-b5e6-96231b3b80d8
to TargetFrameLowering, where it belongs. Incidentally, this allows us
to delete some duplicated (and slightly different!) code in TRI.
There are potentially other layering problems that can be cleaned up
as a result, or in a similar manner.
The refactoring was OK'd by Anton Korobeynikov on llvmdev.
Note: this touches the target interfaces, so out-of-tree targets may
be affected.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175788 91177308-0d34-0410-b5e6-96231b3b80d8
conditions are met:
1. They share the same operand and are in the same BB.
2. Both outputs are used.
3. The target has a native instruction that maps to ISD::FSINCOS node or
the target provides a sincos library call.
Implemented the generic optimization in sdisel and enabled it for
Mac OSX. Also added an additional optimization for x86_64 Mac OSX by
using an alternative entry point __sincos_stret which returns the two
results in xmm0 / xmm1.
rdar://13087969
PR13204
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173755 91177308-0d34-0410-b5e6-96231b3b80d8
a TargetMachine to construct (and thus isn't always available), to an
analysis group that supports layered implementations much like
AliasAnalysis does. This is a pretty massive change, with a few parts
that I was unable to easily separate (sorry), so I'll walk through it.
The first step of this conversion was to make TargetTransformInfo an
analysis group, and to sink the nonce implementations in
ScalarTargetTransformInfo and VectorTargetTranformInfo into
a NoTargetTransformInfo pass. This allows other passes to add a hard
requirement on TTI, and assume they will always get at least on
implementation.
The TargetTransformInfo analysis group leverages the delegation chaining
trick that AliasAnalysis uses, where the base class for the analysis
group delegates to the previous analysis *pass*, allowing all but tho
NoFoo analysis passes to only implement the parts of the interfaces they
support. It also introduces a new trick where each pass in the group
retains a pointer to the top-most pass that has been initialized. This
allows passes to implement one API in terms of another API and benefit
when some other pass above them in the stack has more precise results
for the second API.
The second step of this conversion is to create a pass that implements
the TargetTransformInfo analysis using the target-independent
abstractions in the code generator. This replaces the
ScalarTargetTransformImpl and VectorTargetTransformImpl classes in
lib/Target with a single pass in lib/CodeGen called
BasicTargetTransformInfo. This class actually provides most of the TTI
functionality, basing it upon the TargetLowering abstraction and other
information in the target independent code generator.
The third step of the conversion adds support to all TargetMachines to
register custom analysis passes. This allows building those passes with
access to TargetLowering or other target-specific classes, and it also
allows each target to customize the set of analysis passes desired in
the pass manager. The baseline LLVMTargetMachine implements this
interface to add the BasicTTI pass to the pass manager, and all of the
tools that want to support target-aware TTI passes call this routine on
whatever target machine they end up with to add the appropriate passes.
The fourth step of the conversion created target-specific TTI analysis
passes for the X86 and ARM backends. These passes contain the custom
logic that was previously in their extensions of the
ScalarTargetTransformInfo and VectorTargetTransformInfo interfaces.
I separated them into their own file, as now all of the interface bits
are private and they just expose a function to create the pass itself.
Then I extended these target machines to set up a custom set of analysis
passes, first adding BasicTTI as a fallback, and then adding their
customized TTI implementations.
The fourth step required logic that was shared between the target
independent layer and the specific targets to move to a different
interface, as they no longer derive from each other. As a consequence,
a helper functions were added to TargetLowering representing the common
logic needed both in the target implementation and the codegen
implementation of the TTI pass. While technically this is the only
change that could have been committed separately, it would have been
a nightmare to extract.
The final step of the conversion was just to delete all the old
boilerplate. This got rid of the ScalarTargetTransformInfo and
VectorTargetTransformInfo classes, all of the support in all of the
targets for producing instances of them, and all of the support in the
tools for manually constructing a pass based around them.
Now that TTI is a relatively normal analysis group, two things become
straightforward. First, we can sink it into lib/Analysis which is a more
natural layer for it to live. Second, clients of this interface can
depend on it *always* being available which will simplify their code and
behavior. These (and other) simplifications will follow in subsequent
commits, this one is clearly big enough.
Finally, I'm very aware that much of the comments and documentation
needs to be updated. As soon as I had this working, and plausibly well
commented, I wanted to get it committed and in front of the build bots.
I'll be doing a few passes over documentation later if it sticks.
Commits to update DragonEgg and Clang will be made presently.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171681 91177308-0d34-0410-b5e6-96231b3b80d8
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.
There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.
The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.
I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).
I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
missed in the first pass because the script didn't yet handle include
guards.
Note that the script is now able to handle all of these headers without
manual edits. =]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169224 91177308-0d34-0410-b5e6-96231b3b80d8
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
The TargetTransform changes are breaking LTO bootstraps of clang. I am
working with Nadav to figure out the problem, but I am reverting it for now
to get our buildbots working.
This reverts svn commits: 165665 165669 165670 165786 165787 165997
and I have also reverted clang svn 165741
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166168 91177308-0d34-0410-b5e6-96231b3b80d8
This is a preliminary step toward having TargetPassConfig be able to
start and stop the compilation at specified passes for unit testing
and debugging. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159567 91177308-0d34-0410-b5e6-96231b3b80d8
up to r158925 were handled as processor specific. Making them
generic and putting tests for these modifiers in the CodeGen/Generic
directory caused a number of targets to fail.
This commit addresses that problem by having the targets call
the generic routine for generic modifiers that they don't currently
have explicit code for.
For now only generic print operands 'c' and 'n' are supported.vi
Affected files:
test/CodeGen/Generic/asm-large-immediate.ll
lib/Target/PowerPC/PPCAsmPrinter.cpp
lib/Target/NVPTX/NVPTXAsmPrinter.cpp
lib/Target/ARM/ARMAsmPrinter.cpp
lib/Target/XCore/XCoreAsmPrinter.cpp
lib/Target/X86/X86AsmPrinter.cpp
lib/Target/Hexagon/HexagonAsmPrinter.cpp
lib/Target/CellSPU/SPUAsmPrinter.cpp
lib/Target/Sparc/SparcAsmPrinter.cpp
lib/Target/MBlaze/MBlazeAsmPrinter.cpp
lib/Target/Mips/MipsAsmPrinter.cpp
MSP430 isn't represented because it did not even run with
the long existing 'c' modifier and it was not apparent what
needs to be done to get it inline asm ready.
Contributer: Jack Carter
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159203 91177308-0d34-0410-b5e6-96231b3b80d8
LLVM is now -Wunused-private-field clean except for
- lib/MC/MCDisassembler/Disassembler.h. Not sure why it keeps all those unaccessible fields.
- gtest.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158096 91177308-0d34-0410-b5e6-96231b3b80d8
to pass around a struct instead of a large set of individual values. This
cleans up the interface and allows more information to be added to the struct
for future targets without requiring changes to each and every target.
NV_CONTRIB
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157479 91177308-0d34-0410-b5e6-96231b3b80d8
The TargetPassManager's default constructor wants to initialize the PassManager
to 'null'. But it's illegal to bind a null reference to a null l-value. Make the
ivar a pointer instead.
PR12468
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155902 91177308-0d34-0410-b5e6-96231b3b80d8
This allows us to keep passing reduced masks to SimplifyDemandedBits, but
know about all the bits if SimplifyDemandedBits fails. This allows instcombine
to simplify cases like the one in the included testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154011 91177308-0d34-0410-b5e6-96231b3b80d8
the processor keeps a return addresses stack (RAS) which stores the address
and the instruction execution state of the instruction after a function-call
type branch instruction.
Calling a "noreturn" function with normal call instructions (e.g. bl) can
corrupt RAS and causes 100% return misprediction so LLVM should use a
unconditional branch instead. i.e.
mov lr, pc
b _foo
The "mov lr, pc" is issued in order to get proper backtrace.
rdar://8979299
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151623 91177308-0d34-0410-b5e6-96231b3b80d8
