"optimizeCompareInstr" converts compares (cmp/cmn) into plain sub/add
instructions when the flags are not used anymore. This conversion is valid for
most instructions, but not all. Some instructions that don't set the flags
(e.g. sub with immediate) can set the SP, whereas the flag setting version uses
the same encoding for the "zero" register.
Update the code to also check for the return register before performing the
optimization to make sure that a cmp doesn't suddenly turn into a sub that sets
the stack pointer.
I don't have a test case for this, because it isn't easy to trigger.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222255 91177308-0d34-0410-b5e6-96231b3b80d8
This change emits a COPY for a shift-immediate with a "zero" shift value.
This fixes PR21594 where we emitted a shift instruction with an incorrect
immediate operand.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222247 91177308-0d34-0410-b5e6-96231b3b80d8
The generic FastISel code would bail, because it can't emit a sign-extend for
AArch64. This copies the code over and uses AArch64 specific emit functions.
This is not ideal and 'computeAddress' should handles this, so it can fold the
address computation into the memory operation.
I plan to clean up 'computeAddress' anyways, so I will add that in a future
commit.
Related to rdar://problem/18962471.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221923 91177308-0d34-0410-b5e6-96231b3b80d8
Optimize selects of i1 in the presence of 'true' and 'false' operands to simple
logic operations.
This fixes rdar://problem/18960150.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221848 91177308-0d34-0410-b5e6-96231b3b80d8
This folds the compare emission into the select emission when possible, so we
can directly use the flags and don't have to emit a separate compare.
Related to rdar://problem/18960150.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221847 91177308-0d34-0410-b5e6-96231b3b80d8
With this patch MCDisassembler::getInstruction takes an ArrayRef<uint8_t>
instead of a MemoryObject.
Even on X86 there is a maximum size an instruction can have. Given
that, it seems way simpler and more efficient to just pass an ArrayRef
to the disassembler instead of a MemoryObject and have it do a virtual
call every time it wants some extra bytes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221751 91177308-0d34-0410-b5e6-96231b3b80d8
In the case we optimize an integer extend away and replace it directly with the
source register, we also have to clear all kill flags at all its uses.
This is necessary, because the orignal IR instruction might be trivially dead,
but we replaced it with a nop at MI level.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221628 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes a few cases of:
* Wrong variable name style.
* Lines longer than 80 columns.
* Repeated names in comments.
* clang-format of the above.
This make the next patch a lot easier to read.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221615 91177308-0d34-0410-b5e6-96231b3b80d8
Reversing a CB* instruction used to drop the flags on the condition. On the
included testcase, this lead to a read from an undefined vreg.
Using addOperand keeps the flags, here <undef>.
Differential Revision: http://reviews.llvm.org/D6159
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221507 91177308-0d34-0410-b5e6-96231b3b80d8
While fixing up the register classes in the machine combiner in a previous
commit I missed one.
This fixes the last one and adds a test case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221308 91177308-0d34-0410-b5e6-96231b3b80d8
Some literals in the AArch64 backend had 15 'f's rather than 16, causing
comparisons with a constant 0xffffffffffffffff to be miscompiled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221157 91177308-0d34-0410-b5e6-96231b3b80d8
This removes calls to isMaterializable in the following cases:
* It was redundant with a call to isDeclaration now that isDeclaration returns
the correct answer for materializable functions.
* It was followed by a call to Materialize. Just call Materialize and check EC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221050 91177308-0d34-0410-b5e6-96231b3b80d8
Our internal test reveals such case should not be transformed:
cmp x17, #3
b.lt .LBB10_15
...
subs x12, x12, #1
b.gt .LBB10_1
where x12 is a liveout, becomes:
cmp x17, #2
b.le .LBB10_15
...
subs x12, x12, #2
b.ge .LBB10_1
Unable to provide test case as it's difficult to reproduce on community branch.
http://reviews.llvm.org/D6048
Patch by Zhaoshi Zheng <zhaoshiz@codeaurora.org>!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220987 91177308-0d34-0410-b5e6-96231b3b80d8
Benchmarks have shown that it's harmless to the performance there, and having a
unified set of passes between the two cores where possible helps big.LITTLE
deployment.
Patch by Z. Zheng.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220744 91177308-0d34-0410-b5e6-96231b3b80d8
This is a minor change to use the immediate version when the operand is a null
value. This should get rid of an unnecessary 'mov' instruction in debug
builds and align the code more with the one generated by SelectionDAG.
This fixes rdar://problem/18785125.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220713 91177308-0d34-0410-b5e6-96231b3b80d8
Minor enhancement to use 'tbz' for i1 compare-and-branch to get rid of an 'and'
instruction.
This fixes rdar://problem/18784953.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220712 91177308-0d34-0410-b5e6-96231b3b80d8
The pattern matching for a 'ConstantInt' value was too restrictive. Checking for
a 'Constant' with a bull value is sufficient for using an 'cbz/cbnz' instruction.
This fixes rdar://problem/18784732.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220709 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes a bug where the input register was not defined for the 'tbz/tbnz'
instruction. This happened, because we folded the 'and' instruction from a
different basic block.
This fixes rdar://problem/18784013.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220704 91177308-0d34-0410-b5e6-96231b3b80d8
At higher optimization levels the LLVM IR may contain more complex patterns for
loads/stores from/to frame indices. The 'computeAddress' function wasn't able to
handle this and triggered an assertion.
This fix extends the possible addressing modes for frame indices.
This fixes rdar://problem/18783298.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220700 91177308-0d34-0410-b5e6-96231b3b80d8
sets as keys into a cache of interference matrice values in the Interference
constraint adder.
Creating interference matrices was one of the large remaining time-sinks in
PBQP. Caching them reduces the total compile time (when using PBQP) on the
nightly test suite by ~10%.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220688 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes a miscompilation in the AArch64 fast-isel which was
triggered when a branch is based on an icmp with condition eq or ne,
and type i1, i8 or i16. The cbz instruction compares the whole 32-bit
register, so values with the bottom 1, 8 or 16 bits clear would cause
the wrong branch to be taken.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220553 91177308-0d34-0410-b5e6-96231b3b80d8
This enables targets to adapt their pass pipeline to the register
allocator in use. For example, with the AArch64 backend, using PBQP
with the cortex-a57, the FPLoadBalancing pass is no longer necessary.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220321 91177308-0d34-0410-b5e6-96231b3b80d8
We should be talking about the number of source elements, not the number of destination elements, given we know at this point that the source and dest element numbers are not the same.
While we're at it, avoid writing to std::vector::end()...
Bug found with random testing and a lot of coffee.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220051 91177308-0d34-0410-b5e6-96231b3b80d8
When the constant divisor was larger than 32bits, then the optimized code
generated for the AArch64 backend would emit the wrong code, because the shift
was defined as a shift of a 32bit constant '(1<<Lg2(divisor))' and we would
loose the upper 32bits.
This fixes rdar://problem/18678801.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219934 91177308-0d34-0410-b5e6-96231b3b80d8
This is mostly a copy of the existing FastISel GEP code, but we have to
duplicate it for AArch64, because otherwise we would bail out even for simple
cases. This is because the standard fastEmit functions don't cover MUL at all
and ADD is lowered very inefficientily.
The original commit had a bug in the add emit logic, which has been fixed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219831 91177308-0d34-0410-b5e6-96231b3b80d8
This is a follow up to commit r219742. It removes the CCInMI variable
and accesses the CC in CSCINC directly. In the case of a conditional
branch accessing the CC with CCInMI was wrong.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219748 91177308-0d34-0410-b5e6-96231b3b80d8
Peephole optimization that generates a single conditional branch
for csinc-branch sequences like in the examples below. This is
possible when the csinc sets or clears a register based on a condition
code and the branch checks that register. Also the condition
code may not be modified between the csinc and the original branch.
Examples:
1. Convert csinc w9, wzr, wzr, <CC>;tbnz w9, #0, 0x44
to b.<invCC>
2. Convert csinc w9, wzr, wzr, <CC>; tbz w9, #0, 0x44
to b.<CC>
rdar://problem/18506500
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219742 91177308-0d34-0410-b5e6-96231b3b80d8
This is mostly a copy of the existing FastISel GEP code, but on AArch64 we bail
out even for simple cases, because the standard fastEmit functions don't cover
MUL and ADD is lowered inefficientily.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219726 91177308-0d34-0410-b5e6-96231b3b80d8
Sign-/zero-extend folding depended on the load and the integer extend to be
both selected by FastISel. This cannot always be garantueed and SelectionDAG
might interfer. This commit adds additonal checks to load and integer extend
lowering to catch this.
Related to rdar://problem/18495928.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219716 91177308-0d34-0410-b5e6-96231b3b80d8
e.g Currently we'll generate following instructions if the immediate is too wide:
MOV X0, WideImmediate
ADD X1, BaseReg, X0
LDR X2, [X1, 0]
Using [Base+XReg] addressing mode can save one ADD as following:
MOV X0, WideImmediate
LDR X2, [BaseReg, X0]
Differential Revision: http://reviews.llvm.org/D5477
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219665 91177308-0d34-0410-b5e6-96231b3b80d8
Some early revisions of the Cortex-A53 have an erratum (835769) whereby it is
possible for a 64-bit multiply-accumulate instruction in AArch64 state to
generate an incorrect result. The details are quite complex and hard to
determine statically, since branches in the code may exist in some
circumstances, but all cases end with a memory (load, store, or prefetch)
instruction followed immediately by the multiply-accumulate operation.
The safest work-around for this issue is to make the compiler avoid emitting
multiply-accumulate instructions immediately after memory instructions and the
simplest way to do this is to insert a NOP.
This patch implements such work-around in the backend, enabled via the option
-aarch64-fix-cortex-a53-835769.
The work-around code generation is not enabled by default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219603 91177308-0d34-0410-b5e6-96231b3b80d8
This patch removes the PBQPBuilder class and its subclasses and replaces them
with a composable constraints class: PBQPRAConstraint. This allows constraints
that are only required for optimisation (e.g. coalescing, soft pairing) to be
mixed and matched.
This patch also introduces support for target writers to supply custom
constraints for their targets by overriding a TargetSubtargetInfo method:
std::unique_ptr<PBQPRAConstraints> getCustomPBQPConstraints() const;
This patch should have no effect on allocations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219421 91177308-0d34-0410-b5e6-96231b3b80d8
