Presently, CodeGenPrepare deletes all nearly empty (only phi and branch)
basic blocks. This pass can delete loop preheaders which frequently creates
critical edges. A preheader can be a convenient place to spill registers to
the stack. If the entrance to a loop body is a critical edge, then spills
may occur in the loop body rather than immediately before it. This patch
protects loop preheaders from deletion in CodeGenPrepare even if they are
nearly empty.
Since the patch alters the CFG, it affects a large number of test cases.
In most cases, the changes are merely cosmetic (basic blocks have different
names or instruction orders change slightly). I am somewhat concerned about
the test/CodeGen/Mips/brdelayslot.ll test case. If the loop preheader is not
deleted, then the MIPS backend does not take advantage of a branch delay
slot. Consequently, I would like some close review by a MIPS expert.
The patch also partially subsumes D16893 from George Burgess IV. George
correctly notes that CodeGenPrepare does not actually preserve the dominator
tree. I think the dominator tree was usually not valid when CodeGenPrepare
ran, but I am using LoopInfo to mark preheaders, so the dominator tree is
now always valid before CodeGenPrepare.
Author: Tom Jablin (tjablin)
Reviewers: hfinkel george.burgess.iv vkalintiris dsanders kbarton cycheng
http://reviews.llvm.org/D16984
llvm-svn: 265397
This patch adds support for compact jumps similiar to the previous compact
branch support for MIPSR6. Unlike compact branches, compact jumps do not
have a forbidden slot.
As MipsInstrInfo::getEquivalentCompactForm can determine the correct
expansion for jumps and branches for both microMIPS and MIPSR6, remove the
unnecessary distinction in the delay slot filler.
Reviewers: vkalintiris
Subscribers: llvm-commits, dsanders
llvm-svn: 265390
If the operation's type has been promoted during type legalization, we
need to account for the fact that the high bits of the comparison
operand are likely unspecified.
The LHS is usually zero-extended, but MIPS sign extends it, so we have
to be slightly careful.
Patch by Simon Dardis.
llvm-svn: 264296
Summary:
MIPSR6 introduces a class of branches called compact branches. Unlike the
traditional MIPS branches which have a delay slot, compact branches do not
have a delay slot. The instruction following the compact branch is only
executed if the branch is not taken and must not be a branch.
It works by generating compact branches for MIPS32R6 when the delay slot
filler cannot fill a delay slot. Then, inspecting the generated code for
forbidden slot hazards (a compact branch with an adjacent branch or other
CTI) and inserting nops to clear this hazard.
Patch by Simon Dardis.
Reviewers: vkalintiris, dsanders
Subscribers: MatzeB, dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D16353
llvm-svn: 263444
This reverts commit r262316.
It seems that my change breaks an out-of-tree chromium buildbot, so
I'm reverting this in order to investigate the situation further.
llvm-svn: 262387
Summary:
This patch modifies the existing comparison, branch, conditional-move
and select patterns, and adds new ones where needed. Also, the updated
SLT{u,i,iu} set of instructions generate a GPR width result.
The majority of the code changes in the Mips back-end fix the wrong
assumption that the result of SETCC nodes always produce an i32 value.
The changes in the common code path account for the fact that in 64-bit
MIPS targets, i1 is promoted to i32 instead of i64.
Reviewers: dsanders
Subscribers: dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D10970
llvm-svn: 262316
Summary:
Previously, it would always select DEXT and substitute any invalid matches
for DEXTU/DEXTM during MipsMCCodeEmitter::encodeInstruction(). This works
but causes problems when adding range checked immediates to IAS.
Now isel selects the correct variant up front.
Reviewers: vkalintiris
Subscribers: dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D16810
llvm-svn: 262229
MIPS ABI states that .sbss and .sdata sections must have SHF_MIPS_GPREL
flag. See Figure 4–7 on page 69 in the following document:
ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf.
Differential Revision: http://reviews.llvm.org/D15740
llvm-svn: 259641
Remove the old select.ll file and use select-int.ll, select-flt.ll,
select-dbl.ll for testing selects on integers, floats & doubles respectivelly.
llvm-svn: 259361
Author: milena.vujosevic.janicic
Reviewers: dsanders
FastIsel is not supported for microMIPS, thus it needs to be disabled.
Test micromips-zero-mat-uses.ll is deleted since the tested sequence of instructions is not generated for microMIPS without FastISel.
Differential Revision: http://reviews.llvm.org/D15892
llvm-svn: 259039
For historic reasons, the behavior of .align differs between targets.
Fortunately, there are alternatives, .p2align and .balign, which make the
interpretation of the parameter explicit, and which behave consistently across
targets.
This patch teaches MC to use .p2align instead of .align, so that people reading
code for multiple architectures don't have to remember which way each platform
does its .align directive.
Differential Revision: http://reviews.llvm.org/D16549
llvm-svn: 258750
Summary: The result register is the second operand as per the other mt* instructions.
Reviewers: vkalintiris
Subscribers: llvm-commits, dsanders
Differential Revision: http://reviews.llvm.org/D15993
llvm-svn: 257478
Summary:
It actually takes an offset into the current PC-region.
This fixes the 'expr' command in lldb.
Reviewers: vkalintiris, jaydeep, bhushan
Subscribers: dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D16054
llvm-svn: 257339
This is recommit of r256028 with minor fixes in unittests:
CodeGen/Mips/eh.ll
CodeGen/Mips/insn-zero-size-bb.ll
Original commit message:
When identifying blocks post-dominated by an unreachable-terminated block
in BranchProbabilityInfo, consider only the edge to the normal destination
block if the terminator is InvokeInst and let calcInvokeHeuristics() decide
edge weights for the InvokeInst.
llvm-svn: 256202
It's strange to duplicate the logic for emitting FP values into
emitGlobalConstantDataSequential, and it's even stranger that we end
up printing the verbose assembly comments differently between the two
paths. Just call into emitGlobalConstantFP rather than crudely
duplicating its logic.
llvm-svn: 254988
Summary:
no-odd-spreg-msa.ll: This test deliberately uses an odd-numbered register
in inline assembly and expects the compiler to insert a move to an
even-numbered register.
inlineasm-operand-code.ll and inlineasm_constraint.ll:
Checks for IAS's output will be added once a matcher bug is resolved. This bug
causes the canonical output emitted by IAS to be incorrect for uimm16 constants
with the MSB set. We will still need the non-IAS checks at this point since
these tests primarily test formatting of operands.
Reviewers: vkalintiris
Subscribers: dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D14705
llvm-svn: 254148
Summary:
This is because IAS will delete the comments. NFC at the moment but it will
prevent a failure once IAS is the default.
Reviewers: vkalintiris
Subscribers: llvm-commits, dsanders
Differential Revision: http://reviews.llvm.org/D14704
llvm-svn: 254147
Note, this was reviewed (and more details are in) http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html
These intrinsics currently have an explicit alignment argument which is
required to be a constant integer. It represents the alignment of the
source and dest, and so must be the minimum of those.
This change allows source and dest to each have their own alignments
by using the alignment attribute on their arguments. The alignment
argument itself is removed.
There are a few places in the code for which the code needs to be
checked by an expert as to whether using only src/dest alignment is
safe. For those places, they currently take the minimum of src/dest
alignments which matches the current behaviour.
For example, code which used to read:
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 500, i32 8, i1 false)
will now read:
call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %dest, i8* align 8 %src, i32 500, i1 false)
For out of tree owners, I was able to strip alignment from calls using sed by replacing:
(call.*llvm\.memset.*)i32\ [0-9]*\,\ i1 false\)
with:
$1i1 false)
and similarly for memmove and memcpy.
I then added back in alignment to test cases which needed it.
A similar commit will be made to clang which actually has many differences in alignment as now
IRBuilder can generate different source/dest alignments on calls.
In IRBuilder itself, a new argument was added. Instead of calling:
CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, /* isVolatile */ false)
you now call
CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, SrcAlign, /* isVolatile */ false)
There is a temporary class (IntegerAlignment) which takes the source alignment and rejects
implicit conversion from bool. This is to prevent isVolatile here from passing its default
parameter to the source alignment.
Note, changes in future can now be made to codegen. I didn't change anything here, but this
change should enable better memcpy code sequences.
Reviewed by Hal Finkel.
llvm-svn: 253511
If a section is rw, it is irrelevant if the dynamic linker will write to
it or not.
It looks like llvm implemented this because gcc was doing it. It looks
like gcc implemented this in the hope that it would put all the
relocated items close together and speed up the dynamic linker.
There are two problem with this:
* It doesn't work. Both bfd and gold will map .data.rel to .data and
concatenate the input sections in the order they are seen.
* If we want a feature like that, it can be implemented directly in the
linker since it knowns where the dynamic relocations are.
llvm-svn: 253436
Several places in AsmPrinter.cpp print comments describing MachineOperand
registers using MCRegisterInfo, which uses MCOperand-oriented names. This
doesn't work for targets that use virtual registers exclusively, as
WebAssembly does, since virtual registers are represented and printed
differently.
This patch preserves what seems to be the spirit of r229978, avoiding the
use of TM.getSubtargetImpl(), while still using MachineOperand-oriented
printing for MachineOperands.
Differential Revision: http://reviews.llvm.org/D14709
llvm-svn: 253338
The way prelink used to work was
* The compiler decides if a given section only has relocations that
are know to point to the same DSO. If so, it names it
.data.rel.ro.local<something>.
* The static linker puts all of these together.
* The prelinker program assigns addresses to each library and resolves
the local relocations.
There are many problems with this:
* It is incompatible with address space randomization.
* The information passed by the compiler is redundant. The linker
knows if a given relocation is in the same DSO or not. If could sort
by that if so desired.
* There are newer ways of speeding up DSO (gnu hash for example).
* Even if we want to implement this again in the compiler, the previous
implementation is pretty broken. It talks about relocations that are
"resolved by the static linker". If they are resolved, there are none
left for the prelinker. What one needs to track is if an expression
will require only dynamic relocations that point to the same DSO.
At this point it looks like the prelinker is an historical curiosity.
For example, fedora has retired it because it failed to build for two
releases
(http://pkgs.fedoraproject.org/cgit/prelink.git/commit/?id=eb43100a8331d91c801ee3dcdb0a0bb9babfdc1f)
This patch removes support for it. That is, it stops printing the
".local" sections.
llvm-svn: 253280
Summary:
Without these patterns we would generate a complete LL/SC sequence.
This would be problematic for memory regions marked as WRITE-only or
READ-only, as the instructions LL/SC would read/write to the protected
memory regions correspondingly.
Reviewers: dsanders
Subscribers: llvm-commits, dsanders
Differential Revision: http://reviews.llvm.org/D14397
llvm-svn: 252293
Summary:
This commit resolves wrong opcodes for ll and sc instructions for r6 architecutres, which were generated in method MipsTargetLowering::emitAtomicBinary.
Author: Jelena.Losic
Reviewers: dsanders
Subscribers: dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D13593
llvm-svn: 251629
Summary:
The microMIPS register class GPRMM16 does not contain the $zero register.
However, MipsSEDAGToDAGISel::replaceUsesWithZeroReg() would replace uses
of the $dst register:
[d]addiu, $dst, $zero, 0
with the $zero register, without checking for membership in the register
class of the target machine operand.
Reviewers: dsanders
Subscribers: llvm-commits, dsanders
Differential Revision: http://reviews.llvm.org/D13984
llvm-svn: 251622
Instead of XFAIL-ing the tests with the wrong usage of the "interrupt"
attribute, we should check that we emit the correct error messages to
the user.
llvm-svn: 251295
Summary:
This patch adds support for using the "interrupt" attribute on Mips
for interrupt handling functions. At this time only mips32r2+ with the
o32 ABI with the static relocation model is supported. Unsupported
configurations will be rejected
Patch by Simon Dardis (+ clang-format & some trivial changes to follow the
LLVM coding standards by me).
Reviewers: mpf, dsanders
Subscribers: dsanders, vkalintiris, llvm-commits
Differential Revision: http://reviews.llvm.org/D10768
llvm-svn: 251286
Summary:
Previously, we were inserting an InlineAsm statement for each line of the
inline assembly. This works for GAS but it triggers prologue/epilogue
emission when IAS is in use. This caused:
.set noreorder
.cpload $25
to be emitted as:
.set push
.set reorder
.set noreorder
.set pop
.set push
.set reorder
.cpload $25
.set pop
which led to assembler errors and caused the test to fail.
The whitespace-after-comma changes included in this patch are necessary to
match the output when IAS is in use.
Reviewers: vkalintiris
Subscribers: rkotler, llvm-commits, dsanders
Differential Revision: http://reviews.llvm.org/D13653
llvm-svn: 250895
Summary:
The forwards compatibility strategy employed by MIPS is to consider registers
to be infinitely sign-extended. Then on ISA's with a wider register, the result
of existing instructions are sign-extended to register width and zero-extended
counterparts are added. copy_u.w on MSA32 and copy_u.w on MSA64 violate this
strategy and we have therefore corrected the MSA specs to fix this.
We still keep track of sign/zero-extension during legalization but we now
match copy_s.[wd] where required.
No change required to clang since __builtin_msa_copy_u_[wd] will map to
copy_s.[wd] where appropriate for the target.
Reviewers: vkalintiris
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13472
llvm-svn: 250887
