If sext_inreg is supported, we will turn this into sext_inreg. That
will then remove it if there are enough sign bits. But if sext_inreg
isn't supported, we can still remove the shift pair based on sign
bits.
Split from D95890.
This rewrites big parts of the fast register allocator. The basic
strategy of doing block-local allocation hasn't changed but I tweaked
several details:
Track register state on register units instead of physical
registers. This simplifies and speeds up handling of register aliases.
Process basic blocks in reverse order: Definitions are known to end
register livetimes when walking backwards (contrary when walking
forward then uses may or may not be a kill so we need heuristics).
Check register mask operands (calls) instead of conservatively
assuming everything is clobbered. Enhance heuristics to detect
killing uses: In case of a small number of defs/uses check if they are
all in the same basic block and if so the last one is a killing use.
Enhance heuristic for copy-coalescing through hinting: We check the
first k defs of a register for COPYs rather than relying on there just
being a single definition. When testing this on the full llvm
test-suite including SPEC externals I measured:
average 5.1% reduction in code size for X86, 4.9% reduction in code on
aarch64. (ranging between 0% and 20% depending on the test) 0.5%
faster compiletime (some analysis suggests the pass is slightly slower
than before, but we more than make up for it because later passes are
faster with the reduced instruction count)
Also adds a few testcases that were broken without this patch, in
particular bug 47278.
Patch mostly by Matthias Braun
This seems to have caused incorrect register allocation in some cases,
breaking tests in the Zig standard library (PR47278).
As discussed on the bug, revert back to green for now.
> Record internal state based on register units. This is often more
> efficient as there are typically fewer register units to update
> compared to iterating over all the aliases of a register.
>
> Original patch by Matthias Braun, but I've been rebasing and fixing it
> for almost 2 years and fixed a few bugs causing intermediate failures
> to make this patch independent of the changes in
> https://reviews.llvm.org/D52010.
This reverts commit 66251f7e1d, and
follow-ups 931a68f26b
and 0671a4c508. It also adjust some
test expectations.
Record internal state based on register units. This is often more
efficient as there are typically fewer register units to update
compared to iterating over all the aliases of a register.
Original patch by Matthias Braun, but I've been rebasing and fixing it
for almost 2 years and fixed a few bugs causing intermediate failures
to make this patch independent of the changes in
https://reviews.llvm.org/D52010.
In order to properly implement these atomic we need one register more than other
binary atomics. It is used for storing result from comparing values in addition
to the one that is used for actual result of operation.
https://reviews.llvm.org/D71028
This behavior was added in r130928 for both FastISel and SD, and then
disabled in r131156 for FastISel.
This re-enables it for FastISel with the corresponding fix.
This is triggered only when FastISel can't lower the arguments and falls
back to SelectionDAG for it.
FastISel contains a map of "register fixups" where at the end of the
selection phase it replaces all uses of a register with another
register that FastISel sometimes pre-assigned. Code at the end of
SelectionDAGISel::runOnMachineFunction is doing the replacement at the
very end of the function, while other pieces that come in before that
look through the MachineFunction and assume everything is done. In this
case, the real issue is that the code emitting COPY instructions for the
liveins (physreg to vreg) (EmitLiveInCopies) is checking if the vreg
assigned to the physreg is used, and if it's not, it will skip the COPY.
If a register wasn't replaced with its assigned fixup yet, the copy will
be skipped and we'll end up with uses of undefined registers.
This fix moves the replacement of registers before the emission of
copies for the live-ins.
The initial motivation for this fix is to enable tail calls for
swiftself functions, which were blocked because we couldn't prove that
the swiftself argument (which is callee-save) comes from a function
argument (live-in), because there was an extra copy (vreg to vreg).
A few tests are affected by this:
* llvm/test/CodeGen/AArch64/swifterror.ll: we used to spill x21
(callee-save) but never reload it because it's attached to the return.
We now don't even spill it anymore.
* llvm/test/CodeGen/*/swiftself.ll: we tail-call now.
* llvm/test/CodeGen/AMDGPU/mubuf-legalize-operands.ll: I believe this
test was not really testing the right thing, but it worked because the
same registers were re-used.
* llvm/test/CodeGen/ARM/cmpxchg-O0.ll: regalloc changes
* llvm/test/CodeGen/ARM/swifterror.ll: get rid of a copy
* llvm/test/CodeGen/Mips/*: get rid of spills and copies
* llvm/test/CodeGen/SystemZ/swift-return.ll: smaller stack
* llvm/test/CodeGen/X86/atomic-unordered.ll: smaller stack
* llvm/test/CodeGen/X86/swifterror.ll: same as AArch64
* llvm/test/DebugInfo/X86/dbg-declare-arg.ll: stack size changed
Differential Revision: https://reviews.llvm.org/D62361
llvm-svn: 362963
Trace through multiple COPYs when looking for a physreg source. Add
hinting for vregs that will be copied into physregs (we only hinted
for vregs getting copied to a physreg previously). Give hinted a
register a bonus when deciding which value to spill. This is part of
my rewrite regallocfast series. In fact this one doesn't even have an
effect unless you also flip the allocation to happen from back to
front of a basic block. Nonetheless it helps to split this up to ease
review of D52010
Patch by Matthias Braun
llvm-svn: 360887
This was creating a copy of the register the pseudo itself was
def'ing, leaving a copy of an undefined register. I'm not sure how
the verifier is not catching this, but this avoids asserting in a
future change to RegAllocFast
llvm-svn: 356716
The 2nd loop calculates spill costs but reports free registers as cost
0 anyway, so there is little benefit from having a separate early
loop.
Surprisingly this is not NFC, as many register are marked regDisabled
so the first loop often picks up later registers unnecessarily instead
of the first one available in the allocation order...
Patch by Matthias Braun
llvm-svn: 356499
Set `LiveReg::PhysReg` to zero when freeing a register instead of
removing it from the entry from `LiveRegMap`. This way no iterators get
invalidated and we can avoid passing around and updating iterators all
over the place.
This does not change any allocator decisions. It is not completely NFC
because the arbitrary iteration order through `LiveRegMap` in
`spillAll()` changes so we may get a different order in those spill
sequences (the amount of spills does not change).
This is in preparation of https://reviews.llvm.org/D52010.
llvm-svn: 346298
Similar to PR/25526, fast-regalloc introduces spills at the end of basic
blocks. When this occurs in between an ll and sc, the stores can cause the
atomic sequence to fail.
This patch fixes the issue by introducing more pseudos to represent atomic
operations and moving their lowering to after the expansion of postRA
pseudos.
This version addresses issues with the initial implementation and covers
all atomic operations.
This resolves PR/32020.
Thanks to James Cowgill for reporting the issue!
Patch By: Simon Dardis
Differential Revision: https://reviews.llvm.org/D31287
llvm-svn: 336328
Summary:
N32 and N64 follow the standard ELF conventions (.L) whereas O32 uses its own
($).
This fixes the majority of object differences between -fintegrated-as and
-fno-integrated-as.
Reviewers: sdardis
Subscribers: dsanders, sdardis, llvm-commits
Differential Revision: https://reviews.llvm.org/D22412
llvm-svn: 275967
PR27458 highlights that the MIPS backend does not have well formed
MIR for atomic operations (among other errors).
This patch adds expands and corrects the LL/SC descriptions and uses
for MIPS(64).
Reviewers: dsanders, vkalintiris
Differential Review: http://reviews.llvm.org/D19719
llvm-svn: 272655
Currently Mips::emitAtomicBinaryPartword() does not properly respect the
width of pointers. For MIPS64 this causes the memory address that the ll/sc
sequence uses to be truncated. At runtime this causes a segmentation fault.
This can be fixed by applying similar changes as r266204, so that a full 64bit
pointer is loaded.
Reviewers: dsanders
Differential Review: http://reviews.llvm.org/D19651
llvm-svn: 267900
This change follows up defaults for GCC and Clang, so LLVM does not differ
from them. While number of the test files are touched with this change, they
all keep the old (expected) behaviour with the explicit option:
"-relocation-model=pic"
The tests that have not been touched are insensitive to relocation model.
Differential Revision: http://reviews.llvm.org/D17995
llvm-svn: 265949
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:
For N32/N64, private labels begin with '.L' but for O32 they begin with '$'.
MCAsmInfo now has an initializer function which can be used to provide information from the TargetMachine to control the assembly syntax.
Reviewers: vkalintiris
Reviewed By: vkalintiris
Subscribers: jfb, sandeep, llvm-commits, rafael
Differential Revision: http://reviews.llvm.org/D9821
llvm-svn: 237789
Similar to gep (r230786) and load (r230794) changes.
Similar migration script can be used to update test cases, which
successfully migrated all of LLVM and Polly, but about 4 test cases
needed manually changes in Clang.
(this script will read the contents of stdin and massage it into stdout
- wrap it in the 'apply.sh' script shown in previous commits + xargs to
apply it over a large set of test cases)
import fileinput
import sys
import re
rep = re.compile(r"(getelementptr(?:\s+inbounds)?\s*\()((<\d*\s+x\s+)?([^@]*?)(|\s*addrspace\(\d+\))\s*\*(?(3)>)\s*)(?=$|%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|zeroinitializer|<|\[\[[a-zA-Z]|\{\{)", re.MULTILINE | re.DOTALL)
def conv(match):
line = match.group(1)
line += match.group(4)
line += ", "
line += match.group(2)
return line
line = sys.stdin.read()
off = 0
for match in re.finditer(rep, line):
sys.stdout.write(line[off:match.start()])
sys.stdout.write(conv(match))
off = match.end()
sys.stdout.write(line[off:])
llvm-svn: 232184
Essentially the same as the GEP change in r230786.
A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)
import fileinput
import sys
import re
pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")
for line in sys.stdin:
sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))
Reviewers: rafael, dexonsmith, grosser
Differential Revision: http://reviews.llvm.org/D7649
llvm-svn: 230794
Fix bugs related to atomic microMIPS SC/LL instructions: While expanding atomic
operations the mips32r2 encoding was emitted instead of microMIPS.
Differential Revision: http://reviews.llvm.org/D6659
llvm-svn: 224524
Summary:
... and after all that refactoring, it's possible to distinguish softfloat
floating point values from integers so this patch no longer breaks softfloat to
do it.
Remove direct handling of i32's in the N32/N64 ABI by promoting them to
i64. This more closely reflects the ABI documentation and also fixes
problems with stack arguments on big-endian targets.
We now rely on signext/zeroext annotations (already generated by clang) and
the Assert[SZ]ext nodes to avoid the introduction of unnecessary sign/zero
extends.
It was not possible to convert three tests to use signext/zeroext. These tests
are bswap.ll, ctlz-v.ll, ctlz-v.ll. It's not possible to put signext on a
vector type so we just accept the sign extends here for now. These tests don't
pass the vectors the same way clang does (clang puts multiple elements in the
same argument, these map 1 element to 1 argument) so we don't need to worry too
much about it.
With this patch, all known N32/N64 bugs should be fixed and we now pass the
first 10,000 tests generated by ABITest.py.
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D6117
llvm-svn: 221534
We should update the usages to all of the results;
otherwise, we might get assertion failure or SEGV during
the type legalization of ATOMIC_CMP_SWAP_WITH_SUCCESS
with two or more illegal types.
For example, in the following sequence, both i8 and i1
might be illegal in some target, e.g. armv5, mipsel, mips64el,
%0 = cmpxchg i8* %ptr, i8 %desire, i8 %new monotonic monotonic
%1 = extractvalue { i8, i1 } %0, 1
Since both i8 and i1 should be legalized, the corresponding
ATOMIC_CMP_SWAP_WITH_SUCCESS dag will be checked/replaced/updated
twice.
If we don't update the usage to *ALL* of the results in the
first round, the DAG for extractvalue might be processed earlier.
The GetPromotedInteger() will result in assertion failure,
because its operand (i.e. the success bit of cmpxchg) is not
promoted beforehand.
llvm-svn: 213569
Summary:
The linked-load, store-conditional operations have been re-encoded such
that have a 9-bit offset instead of the 16-bit offset they have prior to
MIPS32r6/MIPS64r6.
While implementing this, I noticed that the atomic load/store pseudos always
emit a sign extension using sll and sra. I have improved this to use seb/seh
when they are available (MIPS32r2/MIPS64r2 and above).
Depends on D4118
Reviewers: jkolek, zoran.jovanovic, vmedic
Reviewed By: vmedic
Differential Revision: http://reviews.llvm.org/D4119
llvm-svn: 211018
Summary:
There is very little difference between the big and little endian cases in
test/CodeGen/Mips/atomic.ll. Merge them together using multiple
FileCheck prefixes.
Depends on D4117
Reviewers: jkolek, zoran.jovanovic, vmedic
Reviewed By: vmedic
Differential Revision: http://reviews.llvm.org/D4118
llvm-svn: 211013
This commit adds a weak variant of the cmpxchg operation, as described
in C++11. A cmpxchg instruction with this modifier is permitted to
fail to store, even if the comparison indicated it should.
As a result, cmpxchg instructions must return a flag indicating
success in addition to their original iN value loaded. Thus, for
uniformity *all* cmpxchg instructions now return "{ iN, i1 }". The
second flag is 1 when the store succeeded.
At the DAG level, a new ATOMIC_CMP_SWAP_WITH_SUCCESS node has been
added as the natural representation for the new cmpxchg instructions.
It is a strong cmpxchg.
By default this gets Expanded to the existing ATOMIC_CMP_SWAP during
Legalization, so existing backends should see no change in behaviour.
If they wish to deal with the enhanced node instead, they can call
setOperationAction on it. Beware: as a node with 2 results, it cannot
be selected from TableGen.
Currently, no use is made of the extra information provided in this
patch. Test updates are almost entirely adapting the input IR to the
new scheme.
Summary for out of tree users:
------------------------------
+ Legacy Bitcode files are upgraded during read.
+ Legacy assembly IR files will be invalid.
+ Front-ends must adapt to different type for "cmpxchg".
+ Backends should be unaffected by default.
llvm-svn: 210903
The syntax for "cmpxchg" should now look something like:
cmpxchg i32* %addr, i32 42, i32 3 acquire monotonic
where the second ordering argument gives the required semantics in the case
that no exchange takes place. It should be no stronger than the first ordering
constraint and cannot be either "release" or "acq_rel" (since no store will
have taken place).
rdar://problem/15996804
llvm-svn: 203559
This update was done with the following bash script:
find test/CodeGen -name "*.ll" | \
while read NAME; do
echo "$NAME"
if ! grep -q "^; *RUN: *llc.*debug" $NAME; then
TEMP=`mktemp -t temp`
cp $NAME $TEMP
sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \
while read FUNC; do
sed -i '' "s/;\(.*\)\([A-Za-z0-9_-]*\):\( *\)$FUNC: *\$/;\1\2-LABEL:\3$FUNC:/g" $TEMP
done
sed -i '' "s/;\(.*\)-LABEL-LABEL:/;\1-LABEL:/" $TEMP
sed -i '' "s/;\(.*\)-NEXT-LABEL:/;\1-NEXT:/" $TEMP
sed -i '' "s/;\(.*\)-NOT-LABEL:/;\1-NOT:/" $TEMP
sed -i '' "s/;\(.*\)-DAG-LABEL:/;\1-DAG:/" $TEMP
mv $TEMP $NAME
fi
done
llvm-svn: 186280
Craig Topper