When a function pointer is replaced with a jumptable pointer, special
case is needed to preserve the semantics of extern_weak functions.
Since a jumptable entry can not be extern_weak, we emulate that
behaviour by replacing all references to F (the extern_weak function)
with the following expression: F != nullptr ? JumpTablePtr : nullptr.
Extra special care is needed for global initializers, since most (or
probably all) backends can not lower an initializer that includes
this kind of constant expression. Initializers like that are replaced
with a global constructor (i.e. a runtime initializer).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286636 91177308-0d34-0410-b5e6-96231b3b80d8
The current implementation is emitting a global constant that happens
to evaluate to the same bytes + relocation as a jump instruction on
X86. This does not work for PIE executables and shared libraries
though, because we end up with a wrong relocation type. And it has no
chance of working on ARM/AArch64 which use different relocation types
for jump instructions (R_ARM_JUMP24) that is never generated for
data.
This change replaces the constant with module-level inline assembly
followed by a hidden declaration of the jump table. Works fine for
ARM/AArch64, but has some drawbacks.
* Extra symbols are added to the static symbol table, which inflate
the size of the unstripped binary a little. Stripped binaries are not
affected. This happens because jump table declarations must be
external (because their body is in the inline asm).
* Original functions that were anonymous are now named
<original name>.cfi, and it affects symbolization sometimes. This is
necessary because the only user of these functions is the (inline
asm) jump table, so they had to be added to @llvm.used, which does
not allow unnamed functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286611 91177308-0d34-0410-b5e6-96231b3b80d8
The r283656 did this in the remark arguments. We also need to do this
in the main function attribute as that is written to YAML as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286482 91177308-0d34-0410-b5e6-96231b3b80d8
Note that the existing metadata checking was re-added by hand because the
script doesn't currently know how to generate checks for lines outside of
functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286460 91177308-0d34-0410-b5e6-96231b3b80d8
Removing the limitation in visitInsertElementInst() causes several regressions
because we're not prepared to fold sequences of shuffles or inserts and extracts
separated by shuffles. Fixing that appears to be a difficult mission because we
are purposely trying to avoid creating shuffles with arbitrary shuffle masks
because some targets may choke on those.
https://llvm.org/bugs/show_bug.cgi?id=30923
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286423 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The change will test the change in r286159.
The idea behind the change: Make the dbg location different between loop header and preheader/exit. Originally, dbg location 21 exists in 3 BBs: preheader, header, critical edge (exit). Update the debug location of inside the loop header from !21 to !22 so that it will reflect the correct location.
Reviewers: probinson
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26428
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286403 91177308-0d34-0410-b5e6-96231b3b80d8
Scalar Evolution asserts when not all the operands of an Add Recurrence
Expression are loop invariants. Loop Strength Reduction should only
create affine Add Recurrences, so that both the start and the step of
the expression are loop invariants.
Differential Revision: https://reviews.llvm.org/D26185
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286347 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: For functions with profile data, we are confident that loop sink will be optimal in sinking code.
Reviewers: davidxl, hfinkel
Subscribers: mehdi_amini, mzolotukhin, llvm-commits
Differential Revision: https://reviews.llvm.org/D26155
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As the test change shows, we can increase the critical path by adding
a 'not' instruction, so make sure that we're actually removing an
instruction if we do this transform.
This transform could also cause us to miss folds of min/max pairs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286315 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
These are good candidates for jump threading. This enables later opts
(such as InstCombine) to combine instructions from the selects with
instructions out of the selects. SimplifyCFG will fold the select
again if unfolding wasn't worth it.
Patch by James Molloy and Pablo Barrio.
Reviewers: rengolin, haicheng, sebpop
Subscribers: jojo, jmolloy, llvm-commits
Differential Revision: https://reviews.llvm.org/D26391
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286236 91177308-0d34-0410-b5e6-96231b3b80d8
This patch avoids scalarization of CTLZ by instead expanding to use CTPOP (ref: "Hacker's Delight") when the necessary operations are available.
This also adds the necessary cost models for X86 SSE2 targets (the main beneficiary) to ensure vectorization only happens when its useful.
Differential Revision: https://reviews.llvm.org/D25910
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With this we get a new field in the YAML record if the value being
streamed out has a debug location. For examples, please see the changes
to the tests.
This is then used in opt-viewer to display a link for the callee
function in the inlining remarks.
Differential Revision: https://reviews.llvm.org/D26366
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286169 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In some specific scenarios with well understood operand bundle types
(like `"deopt"`) it may be possible to go ahead and convert recursion to
iteration, but TailRecursionElimination does not have that logic today
so avoid doing the right thing for now.
I need some input on whether `"funclet"` operand bundles should also
block tail recursion elimination. If not, I'll allow TRE across calls
with `"funclet"` operand bundles and add a test case.
Reviewers: rnk, majnemer, nlewycky, ahatanak
Subscribers: mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D26270
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286147 91177308-0d34-0410-b5e6-96231b3b80d8
Argument evaluation order is one of the edge cases where Clang differs
from GCC, yielding different IR depending on which compiler LLVM was
built with. Make the order deterministic and tune the test to actually
verify the order instead of trying to hide it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286126 91177308-0d34-0410-b5e6-96231b3b80d8
This was reverted at r285866 because there was a crash handling a scalar
select of vectors. I added a check for that pattern and a test case based
on the example provided in the post-commit thread for r285732.
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This reverts commit r285732.
This change introduced a new assertion failure in the following
testcase at -O2:
typedef short __v8hi __attribute__((__vector_size__(16)));
__v8hi foo(__v8hi &V1, __v8hi &V2, unsigned mask) {
__v8hi Result = V1;
if (mask & 0x80)
Result[0] = V2[0];
return Result;
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285866 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
It was detected that the reassociate pass could enter an inifite
loop when analysing dead code. Simply skipping to analyse basic
blocks that are dead avoids such problems (and as a side effect
we avoid spending time on optimising dead code).
The solution is using the same Reverse Post Order ordering of the
basic blocks when doing the optimisations, as when building the
precalculated rank map. A nice side-effect of this solution is
that we now know that we only try to do optimisations for blocks
with ranked instructions.
Fixes https://llvm.org/bugs/show_bug.cgi?id=30818
Reviewers: llvm-commits, davide, eli.friedman, mehdi_amini
Subscribers: dberlin
Differential Revision: https://reviews.llvm.org/D26154
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285793 91177308-0d34-0410-b5e6-96231b3b80d8
I think the former 'test50' had a typo making it functionally equivalent
to the former 'test49'; changed the predicate to provide more coverage.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285706 91177308-0d34-0410-b5e6-96231b3b80d8
This patch introduces the combine:
(C1 shift (A add C2)) -> ((C1 shift C2) shift A)
iff A and C2 are both positive
If both A and C2 are know to be positive then we can safely split into 2 shifts, permitting the folding of the Inner shift.
Fix for the spec benchmark case mentioned by @nadav on PR15141 (assuming we can prove that the inputs as positive).
Differential Revision: https://reviews.llvm.org/D26000
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possible pointer-wrap-around concerns, in some cases.
Before this patch, collectConstStridedAccesses (part of interleaved-accesses
analysis) called getPtrStride with [Assume=false, ShouldCheckWrap=true] when
examining all candidate pointers. This is too conservative. Instead, this
patch makes collectConstStridedAccesses use an optimistic approach, calling
getPtrStride with [Assume=true, ShouldCheckWrap=false], and then, once the
candidate interleave groups have been formed, revisits the pointer-wrapping
analysis but only where it matters: namely, in groups that have gaps, and where
the gaps are not at the very end of the group (in which case the loop is
peeled). This second time getPtrStride is called with [Assume=false,
ShouldCheckWrap=true], but this could further be improved to using Assume=true,
once we also add the logic to track that we are not going to meet the scev
runtime checks threshold.
Differential Revision: https://reviews.llvm.org/D25276
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Try harder to detect obfuscated min/max patterns: the initial pattern was added with D9352 / rL236202.
There was a bug fix for PR27137 at rL264996, but I think we can do better by folding the corresponding
smax pattern and commuted variants.
The codegen tests demonstrate the effect of ValueTracking on the backend via SelectionDAGBuilder. We
can't expose these differences minimally in IR because we don't have smin/smax intrinsics for IR.
Differential Revision: https://reviews.llvm.org/D26091
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Summary:
This "pass" eagerly creates div and rem instructions even when only one
is needed -- it relies on a later pass (machine DCE?) to clean them up.
This is problematic not just from a cleanliness perspective (this pass
is running during CodeGenPrepare, so should leave the IR in a better
state), but it also creates a problem for instruction selection. If we
always have a div+rem, isel will always select a divrem instruction (if
possible), even when a single div or rem would do.
Specifically, in NVPTX, we want to compute rem from the output of div,
if available. But if a div is not available, we want to leave the rem
alone. This transformation is overeager if div is always available.
Because this code runs as part of CodeGenPrepare, it's nontrivial to
write a test for this change. But this will effectively be tested by
a later patch which adds the aforementioned change to NVPTX isel.
Reviewers: tra
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26088
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285460 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In BypassSlowDivision's short-dividend path, we would create e.g.
udiv exact i32 %a, %b
"exact" here means that we are asserting that %a is a multiple of %b.
But we have no reason to believe this must be true -- this is just a
bug, as far as I can tell.
Reviewers: tra
Subscribers: jholewinski, llvm-commits
Differential Revision: https://reviews.llvm.org/D26097
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285459 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes PR 30784. Discussed with Justin, who pointed out that
in the new PassManager infrastructure we can have more fine-grained
control on which analyses we want to preserve, but this is the
best we can do with the current infrastructure.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285380 91177308-0d34-0410-b5e6-96231b3b80d8
