This patch fixes the bug introduced in https://reviews.llvm.org/D35907; the bug is reported by http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20171002/491452.html.
Before D35907, when GetUnderlyingObjects fails to find an identifiable object, allMMOsOkay lambda in getUnderlyingObjectsForInstr returns false and Objects vector is cleared. This behavior is unintentionally changed by D35907.
This patch makes the behavior for such case same as the previous behavior.
Since D35907 introduced a wrapper function getUnderlyingObjectsForCodeGen around GetUnderlyingObjects, getUnderlyingObjectsForCodeGen is modified to return a boolean value to ask the caller to clear the Objects vector.
Differential Revision: https://reviews.llvm.org/D38735
llvm-svn: 315565
parameterized emit() calls
Summary: This is not functional change to adopt new emit() API added in r313691.
Reviewed By: anemet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38285
llvm-svn: 315476
It now knows the tricks of both functions.
Also, fix a bug that considered allocas of non-zero address space to be always non null
Differential Revision: https://reviews.llvm.org/D37628
llvm-svn: 312869
This is a preliminary step towards solving the remaining part of PR27145 - IR for isfinite():
https://bugs.llvm.org/show_bug.cgi?id=27145
In order to solve that one more generally, we need to add matching for and/or of fcmp ord/uno
with a constant operand.
But while looking at those patterns, I realized we were missing a canonicalization for nonzero
constants. Rather than limiting to just folds for constants, we're adding a general value
tracking method for this based on an existing DAG helper.
By transforming everything to 0.0, we can simplify the existing code in foldLogicOfFCmps()
and pick up missing vector folds.
Differential Revision: https://reviews.llvm.org/D37427
llvm-svn: 312591
The function does an equality check later to terminate the recursion, but that won't work if its starts out too high. Similar assert already exists in computeKnownBits.
llvm-svn: 311400
ValueTracking has to strike a balance when attempting to propagate information
backwards from assumes, because if the information is trivially propagated
backwards, it can appear to LLVM that the assumption is known to be true, and
therefore can be removed.
This is sound (because an assumption has no semantic effect except for causing
UB), but prevents the assume from allowing further optimizations.
The isEphemeralValueOf check exists to try and prevent this issue by not
removing the source of an assumption. This tries to make it a little bit more
general to handle the case of side-effectful instructions, such as in
%0 = call i1 @get_val()
%1 = xor i1 %0, true
call void @llvm.assume(i1 %1)
Patch by Ariel Ben-Yehuda, thanks!
Differential Revision: https://reviews.llvm.org/D36590
llvm-svn: 310859
causing compile time issues.
Moreover, the patch *deleted* the flag in addition to changing the
default, and links to a code review that doesn't even discuss the flag
and just has an update to a Clang test case.
I've followed up on the commit thread to ask for numbers on compile time
at this point, leaving the flag in place until things stabilize, and
pointing at specific code that seems to exhibit excessive compile time
with this patch.
Original commit message for r310583:
"""
[ValueTracking] Enabling ValueTracking patch by default (recommit). Part 2.
The original patch was an improvement to IR ValueTracking on
non-negative integers. It has been checked in to trunk (D18777,
r284022). But was disabled by default due to performance regressions.
Perf impact has improved. The patch would be enabled by default.
""""
llvm-svn: 310816
The original patch was an improvement to IR ValueTracking on non-negative
integers. It has been checked in to trunk (D18777, r284022). But was disabled by
default due to performance regressions.
Perf impact has improved. The patch would be enabled by default.
Reviewers: reames, hfinkel
Differential Revision: https://reviews.llvm.org/D34101
Patch by: Olga Chupina <olga.chupina@intel.com>
llvm-svn: 310583
The recently improved support for `icmp` in ValueTracking
(r307304) exposes the fact that `isImplied` condition doesn't
really bail out if we hit the recursion limit (and calls
`computeKnownBits` which increases the depth and asserts).
Differential Revision: https://reviews.llvm.org/D36512
llvm-svn: 310481
I want to reuse this code in SimplifyDemandedBits handling of Add/Sub. This will make that easier.
Wonder if we should use it in SelectionDAG's computeKnownBits too.
Differential Revision: https://reviews.llvm.org/D36433
llvm-svn: 310378
Summary:
This commit allows matchSelectPattern to recognize clamp of float
arguments in the presence of FMF the same way as already done for
integers.
This case is a little different though. With integers, given the
min/max pattern is recognized, DAGBuilder starts selecting MIN/MAX
"automatically". That is not the case for float, because for them only
full FMINNAN/FMINNUM/FMAXNAN/FMAXNUM ISD nodes exist and they do care
about NaNs. On the other hand, some backends (e.g. X86) have only
FMIN/FMAX nodes that do not care about NaNS and the former NAN/NUM
nodes are illegal thus selection is not happening. So I decided to do
such kind of transformation in IR (InstCombiner) instead of
complicating the logic in the backend.
Reviewers: spatel, jmolloy, majnemer, efriedma, craig.topper
Reviewed By: efriedma
Subscribers: hiraditya, javed.absar, n.bozhenov, llvm-commits
Patch by Andrei Elovikov <andrei.elovikov@intel.com>
Differential Revision: https://reviews.llvm.org/D33186
llvm-svn: 310054
This patch is update after the first patch (https://reviews.llvm.org/rL309651) based on the post-commit comments.
Stack coloring pass need to maintain AliasAnalysis information when merging stack slots of different types.
Actually, there is a FIXME comment in StackColoring.cpp
// FIXME: In order to enable the use of TBAA when using AA in CodeGen,
// we'll also need to update the TBAA nodes in MMOs with values
// derived from the merged allocas.
But, TBAA has been already enabled in CodeGen without fixing this pass.
The incorrect TBAA metadata results in recent failures in bootstrap test on ppc64le (PR33928) by allowing unsafe instruction scheduling.
Although we observed the problem on ppc64le, this is a platform neutral issue.
This patch makes the stack coloring pass maintains AliasAnalysis information when merging multiple stack slots.
This patch fixes PR33928.
llvm-svn: 309849
Stack coloring pass need to maintain AliasAnalysis information when merging stack slots of different types.
Actually, there is a FIXME comment in StackColoring.cpp
// FIXME: In order to enable the use of TBAA when using AA in CodeGen,
// we'll also need to update the TBAA nodes in MMOs with values
// derived from the merged allocas.
But, TBAA has been already enabled in CodeGen without fixing this pass.
The incorrect TBAA metadata results in recent failures in bootstrap test on ppc64le (PR33928) by allowing unsafe instruction scheduling.
Although we observed the problem on ppc64le, this is a platform neutral issue.
This patch makes the stack coloring pass maintains AliasAnalysis information when merging multiple stack slots.
llvm-svn: 309651
Prior to this commit both of the added test cases were passing. However, in the
latter case (test7) we were doing a lot more work to arrive at the same answer
(i.e., we were using isImpliedCondMatchingOperands() to determine the
implication.).
llvm-svn: 307400
This patch adds support for handling some forms of ands and ors in
ValueTracking's isImpliedCondition API.
PR33611
https://reviews.llvm.org/D34901
llvm-svn: 307304
Going through the Constant methods requires redetermining that the Constant is a ConstantInt and then calling isZero/isOne/isMinusOne.
llvm-svn: 307292
The original patch was an improvement to IR ValueTracking on non-negative
integers. It has been checked in to trunk (D18777, r284022). But was disabled by
default due to performance regressions.
Perf impact has improved. The patch would be enabled by default.
Reviewers: reames
Differential Revision: https://reviews.llvm.org/D34101
Patch by: Olga Chupina <olga.chupina@intel.com>
llvm-svn: 306528
Summary:
This commit allows matchSelectPattern to recognize clamp of float
arguments in the presence of FMF the same way as already done for
integers.
This case is a little different though. With integers, given the
min/max pattern is recognized, DAGBuilder starts selecting MIN/MAX
"automatically". That is not the case for float, because for them only
full FMINNAN/FMINNUM/FMAXNAN/FMAXNUM ISD nodes exist and they do care
about NaNs. On the other hand, some backends (e.g. X86) have only
FMIN/FMAX nodes that do not care about NaNS and the former NAN/NUM
nodes are illegal thus selection is not happening. So I decided to do
such kind of transformation in IR (InstCombiner) instead of
complicating the logic in the backend.
Reviewers: spatel, jmolloy, majnemer, efriedma, craig.topper
Reviewed By: efriedma
Subscribers: hiraditya, javed.absar, n.bozhenov, llvm-commits
Patch by Andrei Elovikov <andrei.elovikov@intel.com>
Differential Revision: https://reviews.llvm.org/D33186
llvm-svn: 306525
There's an early out that's trying to detect when we don't know any bits that make up the legal range of a shift. The code subtracts one from BitWidth which creates a mask in the lower bits for power of 2 bit widths. This is then ANDed with the known bits to see if any of those bits are known. If the bit width isn't a power of 2 this creates a non-sensical mask.
This patch corrects this by rounding up to a power of 2 before doing the subtract and mask.
Differential Revision: https://reviews.llvm.org/D34165
llvm-svn: 305400
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
llvm-svn: 304787
This will be used by another commit to remove some code from InstSimplify that is redundant for scalars, but was needed for vectors due to this issue.
llvm-svn: 304774
This patch does an inline expansion of memcmp.
It changes the memcmp library call into an inline expansion when the size is
known at compile time and is under a target specified threshold.
This expansion is implemented in CodeGenPrepare and expands into straight line
code. The target specifies a maximum load size and the expansion works by using
this size to load the two sources, compare, and exit early if a difference is
found. It also has a special case when the memcmp result is used in a compare
to zero equality.
Differential Revision: https://reviews.llvm.org/D28637
llvm-svn: 304313
Refactor the strlen optimization code to work for both strlen and wcslen.
This especially helps with programs in the wild where people pass
L"string"s to const std::wstring& function parameters and the wstring
constructor gets inlined.
This also fixes a lingerind API problem/bug in getConstantStringInfo()
where zeroinitializers would always give you an empty string (without a
length) back regardless of the actual length of the initializer which
did not work well in the TrimAtNul==false causing the PR mentioned
below.
Note that the fixed getConstantStringInfo() needed fixes to SelectionDAG
memcpy lowering and may lead to some cases for out-of-bounds
zeroinitializer accesses not getting optimized anymore. So some code
with UB may produce out of bound memory reads now instead of just
producing zeros.
The refactoring "accidentally" fixes http://llvm.org/PR32124
Differential Revision: https://reviews.llvm.org/D32839
llvm-svn: 303461
Summary:
Merge overflow computation for signed add,
appearing both in InstCombine and ValueTracking.
As part of the merge,
cleanup the interface for overflow checks in InstCombine.
Patch by Yoav Ben-Shalom.
Reviewers: craig.topper, majnemer
Reviewed By: craig.topper
Subscribers: takuto.ikuta, llvm-commits
Differential Revision: https://reviews.llvm.org/D32946
llvm-svn: 303029
This patch adds min/max population count, leading/trailing zero/one bit counting methods.
The min methods return answers based on bits that are known without considering unknown bits. The max methods give answers taking into account the largest count that unknown bits could give.
Differential Revision: https://reviews.llvm.org/D32931
llvm-svn: 302925
This patch uses KnownOnes of the input of ctlz/cttz to bound the value that can be returned from these intrinsics. This makes these intrinsics more similar to the handling for ctpop which already uses known bits to produce a similar bound.
Differential Revision: https://reviews.llvm.org/D32521
llvm-svn: 302444
This introduces a new interface for computeKnownBits that returns the KnownBits object instead of requiring it to be pre-constructed and passed in by reference.
This is a much more convenient interface as it doesn't require the caller to figure out the BitWidth to pre-construct the object. It's so convenient that I believe we can use this interface to remove the special ComputeSignBit flavor of computeKnownBits.
As a step towards that idea, this patch replaces all of the internal usages of ComputeSignBit with this new interface. As you can see from the patch there were a couple places where we called ComputeSignBit which really called computeKnownBits, and then called computeKnownBits again directly. I've reduced those places to only making one call to computeKnownBits. I bet there are probably external users that do it too.
A future patch will update the external users and remove the ComputeSignBit interface. I'll also working on moving more locations to the KnownBits returning interface for computeKnownBits.
Differential Revision: https://reviews.llvm.org/D32848
llvm-svn: 302437
This adds routines for reseting KnownBits to unknown, making the value all zeros or all ones. It also adds methods for querying if the value is zero, all ones or unknown.
Differential Revision: https://reviews.llvm.org/D32637
llvm-svn: 302262
I don't believe its possible to have non-zero values here since DataLayout became required. The APInt constructor inside of the KnownBits object will assert if this ever happens.
llvm-svn: 302089
This patch adds zext, sext, and trunc methods to KnownBits and uses them where possible.
Differential Revision: https://reviews.llvm.org/D32784
llvm-svn: 302088
Summary:
programUndefinedIfPoison makes more sense, given what the function
does; and I'm about to add a function with a name similar to
isKnownNotFullPoison (so do the rename to avoid confusion).
Reviewers: broune, majnemer, bjarke.roune
Reviewed By: broune
Subscribers: mcrosier, llvm-commits, mzolotukhin
Differential Revision: https://reviews.llvm.org/D30444
llvm-svn: 301776
Summary: This patch adds isNegative, isNonNegative for querying whether the sign bit is known. It also adds makeNegative and makeNonNegative for controlling the sign bit.
Reviewers: RKSimon, spatel, davide
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32651
llvm-svn: 301747
This patch introduces a new KnownBits struct that wraps the two APInt used by computeKnownBits. This allows us to treat them as more of a unit.
Initially I've just altered the signatures of computeKnownBits and InstCombine's simplifyDemandedBits to pass a KnownBits reference instead of two separate APInt references. I'll do similar to the SelectionDAG version of computeKnownBits/simplifyDemandedBits as a separate patch.
I've added a constructor that allows initializing both APInts to the same bit width with a starting value of 0. This reduces the repeated pattern of initializing both APInts. Once place default constructed the APInts so I added a default constructor for those cases.
Going forward I would like to add more methods that will work on the pairs. For example trunc, zext, and sext occur on both APInts together in several places. We should probably add a clear method that can be used to clear both pieces. Maybe a method to check for conflicting information. A method to return (Zero|One) so we don't write it out everywhere. Maybe a method for (Zero|One).isAllOnesValue() to determine if all bits are known. I'm sure there are many other methods we can come up with.
Differential Revision: https://reviews.llvm.org/D32376
llvm-svn: 301432
This patch uses various APInt methods to reduce temporary APInt creation.
This should be all of the unrelated cleanups that got buried in D32376(creating a KnownBits struct) as well as some pointed out by Simon during the review of that. Plus a few improvements to use counting instead of masking.
I've left out any places where we do something like (KnownZero & KnownOne) != 0 as I plan to add a helper method to KnownBits to ask that question and didn't want to thrash that code an additional time.
Differential Revision: https://reviews.llvm.org/D32495
llvm-svn: 301338
This is a pre-commit for a patch I'm working on to turn KnownZero/One into a struct. Once I do that the type here will be less obvious.
llvm-svn: 301324
This is a pre-commit for a patch that I'm working on to merge KnownZero/KnownOne into a KnownBits struct which would have had to touch this line.
llvm-svn: 301323
getSignBit is a static function that creates an APInt with only the sign bit set. getSignMask seems like a better name to convey its functionality. In fact several places use it and then store in an APInt named SignMask.
Differential Revision: https://reviews.llvm.org/D32108
llvm-svn: 300856
This is preparation for a clang change to improve the [[nodiscard]] warning to not be ignored on methods that return a class marked [[nodiscard]] that are defined in the class itself. See D32207.
We should consider adding wrapper methods to APInt that return the overflow flag directly and discard the APInt result. This would eliminate the void casts and the need to create a bool before the call to pass to the out param.
llvm-svn: 300758
This patch uses lshrInPlace to replace code where the object that lshr is called on is being overwritten with the result.
This adds an lshrInPlace(const APInt &) version as well.
Differential Revision: https://reviews.llvm.org/D32155
llvm-svn: 300566
If we already called computeKnownBits for the RHS being a constant power of 2, we've already computed everything we can and should just stop. I think previously we would still recurse if we had determined the result was negative or had not determined the sign bit at all.
llvm-svn: 300432
The APInt was created from an 'unsigned' and we just wanted to know how many bits the value needed to represent it. We can just use Log2_32 from MathExtras.h to get the info.
llvm-svn: 300309
We call it unconditionally on the operands of the select. Then decide if its a min/max and call it on the min/max operands or on the select operands again. Either of those second calls will overwrite the results of the initial call so we can just delete the first call.
llvm-svn: 300256
Previously it tried to call SimplifyInstruction which doesn't know anything about alloca so defers to constant folding which also doesn't do anything with alloca. This results in wasted cycles making calls that won't do anything. Given the frequency with which this function is called this time adds up.
llvm-svn: 300118
SimplifyDemandedUseBits for Add/Sub already recursed down LHS and RHS for simplifying bits. If that didn't provide any simplifications we fall back to calling computeKnownBits which will recurse again. Instead just take the known bits for LHS and RHS we already have and call into a new function in ValueTracking that can calculate the known bits given the LHS/RHS bits.
llvm-svn: 298711
The code assigned to KnownZero, but later code unconditionally assigned over it. I'm pretty sure the later code can handle the same cases and more equally well.
llvm-svn: 298190
If it is possible for the RHS of a shift operation to be greater than or equal
to the bit-width, then the result might be undef, and we can't report any known
bits.
In some cases, this was allowing a transformation in instcombine which widened
an undef value from i1 to i32, increasing the range of values that a function
could return.
Differential revision: https://reviews.llvm.org/D30781
llvm-svn: 297724
A block with an UnreachableInst does not transfer execution to a successor.
The problem was exposed by GVN-hoist. This patch fixes bug 32153.
Patch by Aditya Kumar.
Differential Revision: https://reviews.llvm.org/D30667
llvm-svn: 297254
Summary:
Previously we used to return a bogus result, 0, for IR like `ashr %val,
-1`.
I've also added an assert checking that `ComputeNumSignBits` at least
returns 1. That assert found an already checked in test case where we
were returning a bad result for `ashr %val, -1`.
Fixes PR32045.
Reviewers: spatel, majnemer
Reviewed By: spatel, majnemer
Subscribers: efriedma, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D30311
llvm-svn: 296273
Summary:
Motivation: fix PR31181 without regression (the actual fix is still in
progress). However, the actual content of PR31181 is not relevant
here.
This change makes poison propagation more aggressive in the following
cases:
1. poision * Val == poison, for any Val. In particular, this changes
existing intentional and documented behavior in these two cases:
a. Val is 0
b. Val is 2^k * N
2. poison << Val == poison, for any Val
3. getelementptr is poison if any input is poison
I think all of these are justified (and are axiomatically true in the
new poison / undef model):
1a: we need poison * 0 to be poison to allow transforms like these:
A * (B + C) ==> A * B + A * C
If poison * 0 were 0 then the above transform could not be allowed
since e.g. we could have A = poison, B = 1, C = -1, making the LHS
poison * (1 + -1) = poison * 0 = 0
and the RHS
poison * 1 + poison * -1 = poison + poison = poison
1b: we need e.g. poison * 4 to be poison since we want to allow
A * 4 ==> A + A + A + A
If poison * 4 were a value with all of their bits poison except the
last four; then we'd not be able to do this transform since then if A
were poison the LHS would only be "partially" poison while the RHS
would be "full" poison.
2: Same reasoning as (1b), we'd like have the following kinds
transforms be legal:
A << 1 ==> A + A
Reviewers: majnemer, efriedma
Subscribers: mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D30185
llvm-svn: 295809
A program may contain llvm.assume info that disagrees with other analysis.
This may be caused by UB in the program, so we must not crash because of that.
As noted in the code comments:
https://llvm.org/bugs/show_bug.cgi?id=31809
...we can do better, but this at least avoids the assert/crash in the bug report.
Differential Revision: https://reviews.llvm.org/D29395
llvm-svn: 293773
Sanjay Patel