The DAGCombiner created a negative shiftamount, stored in an
unsigned variable. Later the optimizer eliminated the shift entirely as being
undefined.
Example: (srl (shl X, 56) 48). ShiftAmt is 4294967288.
Fix it by checking that the shiftamount is positive, and storing in a signed
variable.
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will allow simplifying LegalizeDAG to eliminate type legalization. (I
have a patch to do that, but it's not quite finished; I'll commit it
once it's finished and I've fixed any review comments for this patch.)
See the comment at the beginning of
lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp for more details on the
motivation for this patch.
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code in preparation for code generation. The main thing it does
is handle the case when eh.exception calls (and, in a future
patch, eh.selector calls) are far away from landing pads. Right
now in practice you only find eh.exception calls close to landing
pads: either in a landing pad (the common case) or in a landing
pad successor, due to loop passes shifting them about. However
future exception handling improvements will result in calls far
from landing pads:
(1) Inlining of rewinds. Consider the following case:
In function @f:
...
invoke @g to label %normal unwind label %unwinds
...
unwinds:
%ex = call i8* @llvm.eh.exception()
...
In function @g:
...
invoke @something to label %continue unwind label %handler
...
handler:
%ex = call i8* @llvm.eh.exception()
... perform cleanups ...
"rethrow exception"
Now inline @g into @f. Currently this is turned into:
In function @f:
...
invoke @something to label %continue unwind label %handler
...
handler:
%ex = call i8* @llvm.eh.exception()
... perform cleanups ...
invoke "rethrow exception" to label %normal unwind label %unwinds
unwinds:
%ex = call i8* @llvm.eh.exception()
...
However we would like to simplify invoke of "rethrow exception" into
a branch to the %unwinds label. Then %unwinds is no longer a landing
pad, and the eh.exception call there is then far away from any landing
pads.
(2) Using the unwind instruction for cleanups.
It would be nice to have codegen handle the following case:
invoke @something to label %continue unwind label %run_cleanups
...
handler:
... perform cleanups ...
unwind
This requires turning "unwind" into a library call, which
necessarily takes a pointer to the exception as an argument
(this patch also does this unwind lowering). But that means
you are using eh.exception again far from a landing pad.
(3) Bugpoint simplifications. When bugpoint is simplifying
exception handling code it often generates eh.exception calls
far from a landing pad, which then causes codegen to assert.
Bugpoint then latches on to this assertion and loses sight
of the original problem.
Note that it is currently rare for this pass to actually do
anything. And in fact it normally shouldn't do anything at
all given the code coming out of llvm-gcc! But it does fire
a few times in the testsuite. As far as I can see this is
almost always due to the LoopStrengthReduce codegen pass
introducing pointless loop preheader blocks which are landing
pads and only contain a branch to another block. This other
block contains an eh.exception call. So probably by tweaking
LoopStrengthReduce a bit this can be avoided.
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the 'constract function dbg thingy'. Rename some methods to make them consistent
with the rest of the methods. Move the 'Emit' methods to the end of the file.
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build an integer and cast that to a float. This fixes a crash
caused by trying to split an f32 into two f16's.
This changes the behavior in test/CodeGen/XCore/fneg.ll because that
testcase now triggers a DAGCombine which converts the fneg into an integer
operation. If someone is interested, it's probably possible to tweak
the test to generate an actual fneg.
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function, this could be many, many times. We don't want to re-add variables to
that DIE for each time. We just want to add them once. Check to make sure that
we haven't added them already.
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The following is checked:
* Operand counts: All explicit operands must be present.
* Register classes: All physical and virtual register operands must be
compatible with the register class required by the instruction descriptor.
* Register live intervals: Registers must be defined only once, and must be
defined before use.
The machine code verifier is enabled with the command-line option
'-verify-machineinstrs', or by defining the environment variable
LLVM_VERIFY_MACHINEINSTRS to the name of a file that will receive all the
verifier errors.
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logical/sane approach to organizing all of the stuff that goes into writing out
DWARF information. Honestly? even this is too complex for what it's supposed to
be doing.
Trivia: It *looks* like there would be functionality changes, however there aren't!
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Basically, there was a situation where it was getting an empty vector and doing
a .back() on that. Which isn't cool.
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block with its unique predecessor. Change the code to assert if that is not
the case, instead of trying to handle situations where the block has
multiple predecessors.
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of exception handling builtin sjlj targets in functions turns out not to
be necessary. Marking the intrinsic implementation in the .td file as
defining all registers is sufficient to get the context saved properly by
the containing function.
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Dan was trying to catch the case where a basic block ends with a conditional
branch to the fall-through block. In this case, all the instructions have
been moved out of FromBBI, leaving it empty. It cannot end with a
conditional branch. As the existing comment indicates, it will always fall
through to the next block. If the block already had the next block (NBB)
listed as a successor, the preceding loop has a check for that and does not
remove it. Thus, we need to check and add the successor only when it is
not already listed.
With Dan's change, the empty block often ends up with the fall-through
successor listed twice. This exposed the problem in pr4195, where
CodePlacementOpt did not handle the same predecessor listed more than once.
It is also at least partially responsible for pr4202 and probably a similar
issue with Thumb branches being out of range.
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booleans. This gives a better indication of what the "addReg()" is
doing. Remembering what all of those booleans mean isn't easy, especially if you
aren't spending all of your time in that code.
I took Jakob's suggestion and made it illegal to pass in "true" for the
flag. This should hopefully prevent any unintended misuse of this (by reverting
to the old way of using addReg()).
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belonged. The variable declaration stuff wasn't happy with it where it
was. Sorry that the testcase is so big. Bugpoint wasn't able to reduce it
successfully.
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a supporting preliminary patch for GCC-compatible SjLJ exception handling. Note that these intrinsics are not designed to be invoked directly by the user, but
rather used by the front-end as target hooks for exception handling.
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- moved shrink wrapping code from PrologEpilogInserter.cpp to
new file ShrinkWrapping.cpp.
- moved PEI pass definition into new shared header PEI.h.
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after finding the (unique) layout predecessor. Sometimes a block may be listed
more than once, and processing it more than once in this loop can lead to
inconsistent values for FtTBB/FtFBB, since the AnalyzeBranch method does not
clear these values. There's no point in continuing the loop regardless.
The testcase for this is reduced from the 2003-05-02-DependentPHI SingleSource
test.
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type, rather than assume that it does. If the operand is not vector, it
shouldn't be run through ScalarizeVectorOp. This fixes one of the
testcases in PR3886.
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- reduces _static_ callee saved register spills
and restores similar to Chow's original algorithm.
- iterative implementation with simple heuristic
limits to mitigate compile time impact.
- handles placing spills/restores for multi-entry,
multi-exit regions in the Machine CFG without
splitting edges.
- passes test-suite in LLCBETA mode.
Added contains() method to ADT/SparseBitVector.
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The DwarfWriter expects DbgScopes and DIEs to behave themselves according to
DwarfWriter's rules. However, inlined functions violate these rules. There are
two different types of DIEs associated with an inlined function: an abstract
instance, which has information about the original source code for the function
being inlined; and concrete instances, which are created for each place the
function was inlined and point back to the abstract instance.
This patch tries to stay true to this schema. It bypasses how regular DbgScopes
and DIEs are created and used when necessary. It provides special handling for
DIEs of abstract and concrete instances.
This doesn't take care of all of the problems with debug info for inlined
functions, but it's a step in the right direction. For one thing, llvm-gcc
generates wrong IR (it's missing some llvm.dbg intrinsics at the point where the
function's inlined) for this example:
#include <stdio.h>
static __inline__ __attribute__((always_inline)) int bar(int x) { return 4; }
void foo() {
long long b = 1;
int Y = bar(4);
printf("%d\n", Y);
}
while clang generates correct IR.
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None. However, we were always recording the region end. There's no longer a good
reason for this code to be separated out between the different opt levels, as it
was doing pretty much the same thing anyway.
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inlined function or the end of a function. Before, this was never executing the
"inlined" version of the Record method.
This will become important once the inlined Dwarf writer patch lands.
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concrete instance of an inlined function, we can get the actual address of the
abstract instance inside of the compile unit.
This isn't currently used, but will be by a future check-in.
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scavenger gets confused about register liveness if it doesn't see them.
I'm not thrilled with this solution, but it only comes up when there are dead
copies in the code, which is something that hopefully doesn't happen much.
Here is what happens in pr4100: As shown in the following excerpt from the
debug output of llc, the source of a move gets reloaded from the stack,
inserting a new load instruction before the move. Since that source operand
is a kill, the physical register is free to be reused for the destination
of the move. The move ends up being a no-op, copying R3 to R3, so it is
deleted. But, it leaves behind the load to reload %reg1028 into R3, and
that load is not updated to show that it's destination operand (R3) is dead.
The scavenger gets confused by that load because it thinks that R3 is live.
Starting RegAlloc of: %reg1025<def,dead> = MOVr %reg1028<kill>, 14, %reg0, %reg0
Regs have values:
Reloading %reg1028 into R3
Last use of R3[%reg1028], removing it from live set
Assigning R3 to %reg1025
Register R3 [%reg1025] is never used, removing it from live set
Alternative solutions might be either marking the load as dead, or zapping
the load along with the no-op copy. I couldn't see an easy way to do
either of those, though.
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checking for bcopy... no
checking for getc_unlocked... Assertion failed: (0 && "Unknown SCEV kind!"), function operator(), file /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmCore.roots/llvmCore~obj/src/lib/Analysis/ScalarEvolution.cpp, line 511.
/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmgcc42.roots/llvmgcc42~obj/src/libdecnumber/decUtility.c:360: internal compiler error: Abort trap
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://developer.apple.com/bugreporter> for instructions.
make[4]: *** [decUtility.o] Error 1
make[4]: *** Waiting for unfinished jobs....
Assertion failed: (0 && "Unknown SCEV kind!"), function operator(), file /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmCore.roots/llvmCore~obj/src/lib/Analysis/ScalarEvolution.cpp, line 511.
/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmgcc42.roots/llvmgcc42~obj/src/libdecnumber/decNumber.c:5591: internal compiler error: Abort trap
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://developer.apple.com/bugreporter> for instructions.
make[4]: *** [decNumber.o] Error 1
make[3]: *** [all-stage2-libdecnumber] Error 2
make[3]: *** Waiting for unfinished jobs....
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allow it to have multiple CFG edges to that block. This is needed
to allow MachineBasicBlock::isOnlyReachableByFallthrough to work
correctly. This fixes PR4126.
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shows up in -print-machineinstrs. This doesn't appear to affect anything, but it was
weird for some DBG_LABELs to have DebugLocs but not all of them.
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VirtRegMap keeps track of allocations so it knows what's not used. As a horrible hack, the stack coloring can color spill slots with *free* registers. That is, it replace reload and spills with copies from and to the free register. It unfold instructions that load and store the spill slot and replace them with register using variants.
Not yet enabled. This is part 1. More coming.
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This is *not* turned on by default. Testing indicates this is just as likely to pessimize code. The main issue seems to be allocation preference doesn't work effectively. That will change once I've taught register allocator "swapping".
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memory operands otherwise the writebacks get lost when the inline asm
doesn't otherwise have side effects. This fixes rdar://6839427, though
clang really shouldn't generate these anymore.
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anything larger than 64-bits, avoiding a crash. This should
really be fixed to use APInts, though type legalization happens
to help us out and we get good code on the attached testcase at
least.
This fixes rdar://6836460
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Massive check in. This changes the "-fast" flag to "-O#" in llc. If you want to
use the old behavior, the flag is -O0. This change allows for finer-grained
control over which optimizations are run at different -O levels.
Most of this work was pretty mechanical. The majority of the fixes came from
verifying that a "fast" variable wasn't used anymore. The JIT still uses a
"Fast" flag. I'll change the JIT with a follow-up patch.
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If the physical register does not belong to the virtual register's regclass,
don't coalesce. The physical register could be an invalid operand for an
instruction using the vreg.
The regclass matching is done after determining the actual subregisters being copied.
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Also make the method non-asserting. It will return NULL when given an invalid subreg index.
The method is needed by an upcoming patch.
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use the old behavior, the flag is -O0. This change allows for finer-grained
control over which optimizations are run at different -O levels.
Most of this work was pretty mechanical. The majority of the fixes came from
verifying that a "fast" variable wasn't used anymore. The JIT still uses a
"Fast" flag. I'm not 100% sure if it's necessary to change it there...
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This should have no effect on generated code, but makes the intermediate state
of the coalescer more sane.
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PR2957
ISD::VECTOR_SHUFFLE now stores an array of integers representing the shuffle
mask internal to the node, rather than taking a BUILD_VECTOR of ConstantSDNodes
as the shuffle mask. A value of -1 represents UNDEF.
In addition to eliminating the creation of illegal BUILD_VECTORS just to
represent shuffle masks, we are better about canonicalizing the shuffle mask,
resulting in substantially better code for some classes of shuffles.
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the trunc is directly replaced with the smaller load, so don't
try to create a new sext node. This fixes PR4050.
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This particular one is undefined behavior (although this
isn't related to the crash), so it will no longer do it
at compile time, which seems better.
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ISD::VECTOR_SHUFFLE now stores an array of integers representing the shuffle
mask internal to the node, rather than taking a BUILD_VECTOR of ConstantSDNodes
as the shuffle mask. A value of -1 represents UNDEF.
In addition to eliminating the creation of illegal BUILD_VECTORS just to
represent shuffle masks, we are better about canonicalizing the shuffle mask,
resulting in substantially better code for some classes of shuffles.
A clean up of x86 shuffle code, and some canonicalizing in DAGCombiner is next.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69952 91177308-0d34-0410-b5e6-96231b3b80d8
use ISD::EXTRACT_ELEMENT. SelectionDAG has a special fast-path for
the cast of an EXTRACT_ELEMENT with a BUILD_PAIR operand, for the
common case.
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This fixes a very subtle bug. vr defined by an implicit_def is allowed overlap with any register since it doesn't actually modify anything. However, if it's used as a two-address use, its live range can be extended and it can be spilled. The spiller must take care not to emit a reload for the vn number that's defined by the implicit_def. This is both a correctness and performance issue.
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This makes the extra copyRegToReg calls in ScheduleDAGSDNodesEmit.cpp
unnecessary. Derived from a patch by Jakob Stoklund Olesen.
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in the MachineFunction class, renaming it to addLiveIn for consistency with
the same method in MachineBasicBlock. Thanks for Anton for suggesting this.
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%reg1498<def> = MOV32rm %reg1024, 1, %reg0, 12, %reg0, Mem:LD(4,4) [sunkaddr39 + 0]
%reg1506<def> = MOV32rm %reg1024, 1, %reg0, 8, %reg0, Mem:LD(4,4) [sunkaddr42 + 0]
%reg1486<def> = MOV32rr %reg1506
%reg1486<def> = XOR32rr %reg1486, %reg1498, %EFLAGS<imp-def,dead>
%reg1510<def> = MOV32rm %reg1024, 1, %reg0, 4, %reg0, Mem:LD(4,4) [sunkaddr45 + 0]
=>
%reg1498<def> = MOV32rm %reg2036, 1, %reg0, 12, %reg0, Mem:LD(4,4) [sunkaddr39 + 0]
%reg1506<def> = MOV32rm %reg2037, 1, %reg0, 8, %reg0, Mem:LD(4,4) [sunkaddr42 + 0]
%reg1486<def> = MOV32rr %reg1506
%reg1486<def> = XOR32rr %reg1486, %reg1498, %EFLAGS<imp-def,dead>
%reg1510<def> = MOV32rm %reg2038, 1, %reg0, 4, %reg0, Mem:LD(4,4) [sunkaddr45 + 0]
From linearscan's point of view, each of reg2036, 2037, and 2038 are separate registers, each is "killed" after a single use. The reloaded register is available and it's often clobbered right away. e.g. In thise case reg1498 is allocated EAX while reg2036 is allocated RAX. This means we end up with multiple reloads from the same stack slot in the same basic block.
Now linearscan recognize there are other reloads from same SS in the same BB. So it'll "downgrade" RAX (and its aliases) after reg2036 is allocated until the next reload (reg2037) is done. This greatly increase the likihood reloads from SS are reused.
This speeds up sha1 from OpenSSL by 5.8%. It is also an across the board win for SPEC2000 and 2006.
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bigger than the vector element type, turn checking
of the operand type back on again, appropriately
adjusted.
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type as the vector element type: allow them to be of
a wider integer type than the element type all the way
through the system, and not just as far as LegalizeDAG.
This should be safe because it used to be this way
(the old type legalizer would produce such nodes), so
backends should be able to handle it. In fact only
targets which have legal vector types with an illegal
promoted element type will ever see this (eg: <4 x i16>
on ppc). This fixes a regression with the new type
legalizer (vec_splat.ll). Also, treat SCALAR_TO_VECTOR
the same as BUILD_VECTOR. After all, it is just a
special case of BUILD_VECTOR.
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register is available and when it's profitable.
e.g.
xorq %r12<kill>, %r13
addq %rax, -184(%rbp)
addq %r13, -184(%rbp)
==>
xorq %r12<kill>, %r13
movq -184(%rbp), %r12
addq %rax, %r12
addq %r13, %r12
movq %r12, -184(%rbp)
Two more instructions, but fewer memory accesses. It can also open up
opportunities for more optimizations.
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add dependencies on nodes with exactly one successor which is a
COPY_TO_REGCLASS node. In the case that the copy is coalesced
away, the dependence should be on the user of the copy, rather
than the copy itself.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69309 91177308-0d34-0410-b5e6-96231b3b80d8
to support replacing a node with another that has a superset of
the result types. Use this instead of calling
ReplaceAllUsesOfValueWith for each value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69209 91177308-0d34-0410-b5e6-96231b3b80d8