| Commit message (Collapse) | Author | Age | Files | Lines |
... | |
|
|
|
|
|
| |
Oddly, I had to change a value name from "tmp0" to "bc0" to get the autogened test to pass. I'm putting this down to an oddity of update_test_checks or FileCheck, but don't understand it.
llvm-svn: 362532
|
|
|
|
|
|
| |
result
llvm-svn: 362518
|
|
|
|
| |
llvm-svn: 362516
|
|
|
|
|
|
|
|
| |
(Recommit after fixing a keymash in the run line. Sorry for breakage.)
This is preparation for D62625 <https://reviews.llvm.org/D62625>
llvm-svn: 362426
|
|
|
|
|
|
| |
This reverts commit r362417. There's a syntax error in the RUN line.
llvm-svn: 362418
|
|
|
|
|
|
| |
This is preparation for D62625
llvm-svn: 362417
|
|
|
|
|
|
| |
These saturating math ops can be replaced with simple math.
llvm-svn: 362320
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
Fix for https://bugs.llvm.org/show_bug.cgi?id=31181 and partial fix
for LFTR poison handling issues in general.
When LFTR moves a condition from pre-inc to post-inc, it may now
depend on value that is poison due to nowrap flags. To avoid this,
we clear any nowrap flag that SCEV cannot prove for the post-inc
addrec.
Additionally, LFTR may switch to a different IV that is dynamically
dead and as such may be arbitrarily poison. This patch will correct
nowrap flags in some but not all cases where this happens. This is
related to the adoption of IR nowrap flags for the pre-inc addrec.
(See some of the switch_to_different_iv tests, where flags are not
dropped or insufficiently dropped.)
Finally, there are likely similar issues with the handling of GEP
inbounds, but we don't have a test case for this yet.
Differential Revision: https://reviews.llvm.org/D60935
llvm-svn: 362292
|
|
|
|
|
|
|
| |
Two more tests with a switch to a dynamically dead IV, with poison
occuring on the first or second iteration.
llvm-svn: 362291
|
|
|
|
|
|
|
|
| |
One case where overflow happens in the first loop iteration, and
two cases where we switch to a dynamically dead IV with post/pre
increment, respectively.
llvm-svn: 361189
|
|
|
|
|
|
| |
These are all of the ones involving the same data layout string. Remainder take a bit more consideration, but at least everything can be auto-updated now.
llvm-svn: 360961
|
|
|
|
|
|
| |
Newly written tests to cover the simple cases. We don't appear to have broad coverage of this transform anywhere.
llvm-svn: 360957
|
|
|
|
| |
llvm-svn: 360936
|
|
|
|
|
|
| |
This test hadn't been fully reduced, so do so.
llvm-svn: 360935
|
|
|
|
| |
llvm-svn: 360934
|
|
|
|
| |
llvm-svn: 360933
|
|
|
|
| |
llvm-svn: 360932
|
|
|
|
| |
llvm-svn: 360931
|
|
|
|
|
|
| |
Noticed while glancing through the code for other reasons. The extension is trivial enough, decided to just do it.
llvm-svn: 360694
|
|
|
|
| |
llvm-svn: 360690
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
Summary:
Currently we express umin as `~umax(~x, ~y)`. However, this becomes
a problem for operands in non-integral pointer spaces, because `~x`
is not something we can compute for `x` non-integral. However, since
comparisons are generally still allowed, we are actually able to
express `umin(x, y)` directly as long as we don't try to express is
as a umax. Support this by adding an explicit umin/smin representation
to SCEV. We do this by factoring the existing getUMax/getSMax functions
into a new function that does all four. The previous two functions were
largely identical.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D50167
llvm-svn: 360159
|
|
|
|
| |
llvm-svn: 358813
|
|
|
|
| |
llvm-svn: 358812
|
|
|
|
|
|
|
|
| |
The reversion apparently deleted the test/Transforms directory.
Will be re-reverting again.
llvm-svn: 358552
|
|
|
|
|
|
|
|
| |
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
A SCEV is not low-cost just because you can divide it by a power of 2. We need to also
check what we are dividing to make sure it too is not a high-code expansion. This helps
to not expand the exit value of certain loops, helping not to bloat the code.
The change in no-iv-rewrite.ll is reverting back to what it was testing before rL194116,
and looks a lot like the other tests in replace-loop-exit-folds.ll.
Differential Revision: https://reviews.llvm.org/D58435
llvm-svn: 355393
|
|
|
|
|
|
|
|
|
|
|
| |
Add some tests for various loops of the form:
while(S >= 32) {
S -= 32;
something();
};
return S;
llvm-svn: 355389
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
In some cases, MaxBECount can be less precise than ExactBECount for AND
and OR (the AND case was PR26207). In the OR test case, both ExactBECounts are
undef, but MaxBECount are different, so we hit the assertion below. This
patch uses the same solution the AND case already uses.
Assertion failed:
((isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute>(MaxNotTaken))
&& "Exact is not allowed to be less precise than Max"), function ExitLimit
This patch also consolidates test cases for both AND and OR in a single
test case.
Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=13245
Reviewers: sanjoy, efriedma, mkazantsev
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D58853
llvm-svn: 355259
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
Logic in `getInsertPointForUses` doesn't account for a corner case when `Def`
only comes to a Phi user from unreachable blocks. In this case, the incoming
value may be arbitrary (and not even available in the input block) and break
the loop-related invariants that are asserted below.
In fact, if we encounter this situation, no IR modification is needed. This
Phi will be simplified away with nearest cleanup.
Differential Revision: https://reviews.llvm.org/D58045
Reviewed By: spatel
llvm-svn: 353816
|
|
|
|
| |
llvm-svn: 353693
|
|
|
|
| |
llvm-svn: 353688
|
|
|
|
|
|
|
|
|
|
| |
The patch has been reverted because it ended up prohibiting propagation
of a constant to exit value. For such values, we should skip all checks
related to hard uses because propagating a constant is always profitable.
Differential Revision: https://reviews.llvm.org/D53691
llvm-svn: 346397
|
|
|
|
| |
llvm-svn: 346199
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
This reverts commit 2f425e9c7946b9d74e64ebbfa33c1caa36914402.
It seems that the check that we still should do the transform if we
know the result is constant is missing in this code. So the logic that
has been deleted by this change is still sometimes accidentally useful.
I revert the change to see what can be done about it. The motivating
case is the following:
@Y = global [400 x i16] zeroinitializer, align 1
define i16 @foo() {
entry:
br label %for.body
for.body: ; preds = %entry, %for.body
%i = phi i16 [ 0, %entry ], [ %inc, %for.body ]
%arrayidx = getelementptr inbounds [400 x i16], [400 x i16]* @Y, i16 0, i16 %i
store i16 0, i16* %arrayidx, align 1
%inc = add nuw nsw i16 %i, 1
%cmp = icmp ult i16 %inc, 400
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.body
%inc.lcssa = phi i16 [ %inc, %for.body ]
ret i16 %inc.lcssa
}
We should be able to figure out that the result is constant, but the patch
breaks it.
Differential Revision: https://reviews.llvm.org/D51584
llvm-svn: 346198
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
When rewriting loop exit values, IndVars considers this transform not profitable if
the loop instruction has a loop user which it believes cannot be optimized away.
In current implementation only calls that immediately use the instruction are considered
as such.
This patch extends the definition of "hard" users to any side-effecting instructions
(which usually cannot be optimized away from the loop) and also allows handling
of not just immediate users, but use chains.
Differentlai Revision: https://reviews.llvm.org/D51584
Reviewed By: etherzhhb
llvm-svn: 345814
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
For some unclear reason rewriteLoopExitValues considers recalculation
after the loop profitable if it has some "soft uses" outside the loop (i.e. any
use other than call and return), even if we have proved that it has a user inside
the loop which we think will not be optimized away.
There is no existing unit test that would explain this. This patch provides an
example when rematerialisation of exit value is not profitable but it passes
this check due to presence of a "soft use" outside the loop.
It makes no sense to recalculate value on exit if we are going to compute it
due to some irremovable within the loop. This patch disallows applying this
transform in the described situation.
Differential Revision: https://reviews.llvm.org/D51581
Reviewed By: etherzhhb
llvm-svn: 345708
|
|
|
|
|
|
|
|
|
|
|
|
| |
There is a transform that may replace `lshr (x+1), 1` with `lshr x, 1` in case
if it can prove that the result will be the same. However the initial instruction
might have an `exact` flag set, and it now should be dropped unless we prove
that it may hold. Incorrectly set `exact` attribute may then produce poison.
Differential Revision: https://reviews.llvm.org/D53061
Reviewed By: sanjoy
llvm-svn: 344223
|
|
|
|
|
|
|
|
|
|
|
| |
A piece of logic in rewriteLoopExitValues has a weird check on number of
users which allowed an unprofitable transform in case if an instruction has
more than 6 users.
Differential Revision: https://reviews.llvm.org/D51404
Reviewed By: etherzhhb
llvm-svn: 342444
|
|
|
|
| |
llvm-svn: 342131
|
|
|
|
| |
llvm-svn: 341904
|
|
|
|
|
|
|
|
|
|
|
| |
Currently, `sinkUnusedInvariants` does not set Changed flag even if it makes
changes in the IR. There is no clear evidence that it can cause a crash, but it
looks highly suspicious and likely invalid.
Differential Revision: https://reviews.llvm.org/D51777
Reviewed By: skatkov
llvm-svn: 341777
|
|
|
|
|
|
|
|
| |
Laod operand.
Differential Revision: https://reviews.llvm.org/D49151
llvm-svn: 341726
|
|
|
|
|
|
|
|
|
|
|
| |
IndVars does not set `Changed` flag when it eliminates dead instructions. As result,
it may make IR modifications and report that it has done nothing. It leads to inconsistent
preserved analyzes results.
Differential Revision: https://reviews.llvm.org/D51770
Reviewed By: skatkov
llvm-svn: 341633
|
|
|
|
| |
llvm-svn: 341456
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
This patch removes the function `expandSCEVIfNeeded` which behaves not as
it was intended. This function tries to make a lookup for exact existing expansion
and only goes to normal expansion via `expandCodeFor` if this lookup hasn't found
anything. As a result of this, if some instruction above the loop has a `SCEVConstant`
SCEV, this logic will return this instruction when asked for this `SCEVConstant` rather
than return a constant value. This is both non-profitable and in some cases leads to
breach of LCSSA form (as in PR38674).
Whether or not it is possible to break LCSSA with this algorithm and with some
non-constant SCEVs is still in question, this is still being investigated. I wasn't
able to construct such a test so far, so maybe this situation is impossible. If it is,
it will go as a separate fix.
Rather than do it, it is always correct to just invoke `expandCodeFor` unconditionally:
it behaves smarter about insertion points, and as side effect of this it will choose a
constant value for SCEVConstants. For other SCEVs it may end up finding a better insertion
point. So it should not be worse in any case.
NOTE: So far the only known case for which this transform may break LCSSA is mapping
of SCEVConstant to an instruction. However there is a suspicion that the entire algorithm
can compromise LCSSA form for other cases as well (yet not proved).
Differential Revision: https://reviews.llvm.org/D51286
Reviewed By: etherzhhb
llvm-svn: 341345
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
This patch issues an error message if Darwin ABI is attempted with the PPC
backend. It also cleans up existing test cases, either converting the test to
use an alternative triple or removing the test if the coverage is no longer
needed.
Updated Tests
-------------
The majority of test cases were updated to use a different triple that does not
include the Darwin ABI. Many tests were also updated to use FileCheck, in place
of grep.
Deleted Tests
-------------
llvm/test/tools/dsymutil/PowerPC/sibling.test was originally added to test
specific functionality of dsymutil using an object file created with an old
version of llvm-gcc for a Powerbook G4. After a discussion with @JDevlieghere he
suggested removing the test.
llvm/test/CodeGen/PowerPC/combine_loads_from_build_pair.ll was converted from a
PPC test to a SystemZ test, as the behavior is also reproducible there.
All other tests that were deleted were specific to the darwin/ppc ABI and no
longer necessary.
Phabricator Review: https://reviews.llvm.org/D50988
llvm-svn: 340795
|
|
|
|
|
|
|
|
|
|
|
| |
This is a follow-up for the patch rL335020. When we replace compares against
trunc with compares against wide IV, we can also replace signed predicates with
unsigned where it is legal.
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D48763
llvm-svn: 338115
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
as well as sext(C + x + ...) -> (D + sext(C-D + x + ...))<nuw><nsw>
similar to the equivalent transformation for zext's
if the top level addition in (D + (C-D + x * n)) could be proven to
not wrap, where the choice of D also maximizes the number of trailing
zeroes of (C-D + x * n), ensuring homogeneous behaviour of the
transformation and better canonicalization of such AddRec's
(indeed, there are 2^(2w) different expressions in `B1 + ext(B2 + Y)` form for
the same Y, but only 2^(2w - k) different expressions in the resulting `B3 +
ext((B4 * 2^k) + Y)` form, where w is the bit width of the integral type)
This patch generalizes sext(C1 + C2*X) --> sext(C1) + sext(C2*X) and
sext{C1,+,C2} --> sext(C1) + sext{0,+,C2} transformations added in
r209568 relaxing the requirements the following way:
1. C2 doesn't have to be a power of 2, it's enough if it's divisible by 2
a sufficient number of times;
2. C1 doesn't have to be less than C2, instead of extracting the entire
C1 we can split it into 2 terms: (00...0XXX + YY...Y000), keep the
second one that may cause wrapping within the extension operator, and
move the first one that doesn't affect wrapping out of the extension
operator, enabling further simplifications;
3. C1 and C2 don't have to be positive, splitting C1 like shown above
produces a sum that is guaranteed to not wrap, signed or unsigned;
4. in AddExpr case there could be more than 2 terms, and in case of
AddExpr the 2nd and following terms and in case of AddRecExpr the
Step component don't have to be in the C2*X form or constant
(respectively), they just need to have enough trailing zeros,
which in turn could be guaranteed by means other than arithmetics,
e.g. by a pointer alignment;
5. the extension operator doesn't have to be a sext, the same
transformation works and profitable for zext's as well.
Apparently, optimizations like SLPVectorizer currently fail to
vectorize even rather trivial cases like the following:
double bar(double *a, unsigned n) {
double x = 0.0;
double y = 0.0;
for (unsigned i = 0; i < n; i += 2) {
x += a[i];
y += a[i + 1];
}
return x * y;
}
If compiled with `clang -std=c11 -Wpedantic -Wall -O3 main.c -S -o - -emit-llvm`
(!{!"clang version 7.0.0 (trunk 337339) (llvm/trunk 337344)"})
it produces scalar code with the loop not unrolled with the unsigned `n` and
`i` (like shown above), but vectorized and unrolled loop with signed `n` and
`i`. With the changes made in this commit the unsigned version will be
vectorized (though not unrolled for unclear reasons).
How it all works:
Let say we have an AddExpr that looks like (C + x + y + ...), where C
is a constant and x, y, ... are arbitrary SCEVs. Let's compute the
minimum number of trailing zeroes guaranteed of that sum w/o the
constant term: (x + y + ...). If, for example, those terms look like
follows:
i
XXXX...X000
YYYY...YY00
...
ZZZZ...0000
then the rightmost non-guaranteed-zero bit (a potential one at i-th
position above) can change the bits of the sum to the left (and at
i-th position itself), but it can not possibly change the bits to the
right. So we can compute the number of trailing zeroes by taking a
minimum between the numbers of trailing zeroes of the terms.
Now let's say that our original sum with the constant is effectively
just C + X, where X = x + y + .... Let's also say that we've got 2
guaranteed trailing zeros for X:
j
CCCC...CCCC
XXXX...XX00 // this is X = (x + y + ...)
Any bit of C to the left of j may in the end cause the C + X sum to
wrap, but the rightmost 2 bits of C (at positions j and j - 1) do not
affect wrapping in any way. If the upper bits cause a wrap, it will be
a wrap regardless of the values of the 2 least significant bits of C.
If the upper bits do not cause a wrap, it won't be a wrap regardless
of the values of the 2 bits on the right (again).
So let's split C to 2 constants like follows:
0000...00CC = D
CCCC...CC00 = (C - D)
and represent the whole sum as D + (C - D + X). The second term of
this new sum looks like this:
CCCC...CC00
XXXX...XX00
----------- // let's add them up
YYYY...YY00
The sum above (let's call it Y)) may or may not wrap, we don't know,
so we need to keep it under a sext/zext. Adding D to that sum though
will never wrap, signed or unsigned, if performed on the original bit
width or the extended one, because all that that final add does is
setting the 2 least significant bits of Y to the bits of D:
YYYY...YY00 = Y
0000...00CC = D
----------- <nuw><nsw>
YYYY...YYCC
Which means we can safely move that D out of the sext or zext and
claim that the top-level sum neither sign wraps nor unsigned wraps.
Let's run an example, let's say we're working in i8's and the original
expression (zext's or sext's operand) is 21 + 12x + 8y. So it goes
like this:
0001 0101 // 21
XXXX XX00 // 12x
YYYY Y000 // 8y
0001 0101 // 21
ZZZZ ZZ00 // 12x + 8y
0000 0001 // D
0001 0100 // 21 - D = 20
ZZZZ ZZ00 // 12x + 8y
0000 0001 // D
WWWW WW00 // 21 - D + 12x + 8y = 20 + 12x + 8y
therefore zext(21 + 12x + 8y) = (1 + zext(20 + 12x + 8y))<nuw><nsw>
This approach could be improved if we move away from using trailing
zeroes and use KnownBits instead. For instance, with KnownBits we could
have the following picture:
i
10 1110...0011 // this is C
XX X1XX...XX00 // this is X = (x + y + ...)
Notice that some of the bits of X are known ones, also notice that
known bits of X are interspersed with unknown bits and not grouped on
the rigth or left.
We can see at the position i that C(i) and X(i) are both known ones,
therefore the (i + 1)th carry bit is guaranteed to be 1 regardless of
the bits of C to the right of i. For instance, the C(i - 1) bit only
affects the bits of the sum at positions i - 1 and i, and does not
influence if the sum is going to wrap or not. Therefore we could split
the constant C the following way:
i
00 0010...0011 = D
10 1100...0000 = (C - D)
Let's compute the KnownBits of (C - D) + X:
XX1 1 = carry bit, blanks stand for known zeroes
10 1100...0000 = (C - D)
XX X1XX...XX00 = X
--- -----------
XX X0XX...XX00
Will this add wrap or not essentially depends on bits of X. Adding D
to this sum, however, is guaranteed to not to wrap:
0 X
00 0010...0011 = D
sX X0XX...XX00 = (C - D) + X
--- -----------
sX XXXX XX11
As could be seen above, adding D preserves the sign bit of (C - D) +
X, if any, and has a guaranteed 0 carry out, as expected.
The more bits of (C - D) we constrain, the better the transformations
introduced here canonicalize expressions as it leaves less freedom to
what values the constant part of ((C - D) + x + y + ...) can take.
Reviewed By: mzolotukhin, efriedma
Differential Revision: https://reviews.llvm.org/D48853
llvm-svn: 337943
|
|
|
|
|
|
|
| |
If a trunc has a user in a block which is not reachable from entry,
we can safely perform trunc elimination as if this user didn't exist.
llvm-svn: 335816
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
This patch adds logic to deal with the following constructions:
%iv = phi i64 ...
%trunc = trunc i64 %iv to i32
%cmp = icmp <pred> i32 %trunc, %invariant
Replacing it with
%iv = phi i64 ...
%cmp = icmp <pred> i64 %iv, sext/zext(%invariant)
In case if it is legal. Specifically, if `%iv` has signed comparison users, it is
required that `sext(trunc(%iv)) == %iv`, and if it has unsigned comparison
uses then we require `zext(trunc(%iv)) == %iv`. The current implementation
bails if `%trunc` has other uses than `icmp`, but in theory we can handle more
cases here (e.g. if the user of trunc is bitcast).
Differential Revision: https://reviews.llvm.org/D47928
Reviewed By: reames
llvm-svn: 335020
|