Match a pattern where a wide type scalar value is loaded by several narrow loads and combined by shifts and ors. Fold it into a single load or a load and a bswap if the targets supports it.
Assuming little endian target:
i8 *a = ...
i32 val = a[0] | (a[1] << 8) | (a[2] << 16) | (a[3] << 24)
=>
i32 val = *((i32)a)
i8 *a = ...
i32 val = (a[0] << 24) | (a[1] << 16) | (a[2] << 8) | a[3]
=>
i32 val = BSWAP(*((i32)a))
This optimization was discussed on llvm-dev some time ago in "Load combine pass" thread. We came to the conclusion that we want to do this transformation late in the pipeline because in presence of atomic loads load widening is irreversible transformation and it might hinder other optimizations.
Eventually we'd like to support folding patterns like this where the offset has a variable and a constant part:
i32 val = a[i] | (a[i + 1] << 8) | (a[i + 2] << 16) | (a[i + 3] << 24)
Matching the pattern above is easier at SelectionDAG level since address reassociation has already happened and the fact that the loads are adjacent is clear. Understanding that these loads are adjacent at IR level would have involved looking through geps/zexts/adds while looking at the addresses.
The general scheme is to match OR expressions by recursively calculating the origin of individual bits which constitute the resulting OR value. If all the OR bits come from memory verify that they are adjacent and match with little or big endian encoding of a wider value. If so and the load of the wider type (and bswap if needed) is allowed by the target generate a load and a bswap if needed.
Reviewed By: hfinkel, RKSimon, filcab
Differential Revision: https://reviews.llvm.org/D26149
llvm-svn: 289538
N32 relocations are only correct for individual relocations at the moment.
Support for relocation composition will follow in a later patch.
Patch By: Daniel Sanders
Reviwers: vkalintiris, atanasyan
Differential Revision: https://reviews.llvm.org/D27467
llvm-svn: 289532
In certain cases it is possible that transient instructions such as
%reg = IMPLICIT_DEF as a single instruction in a basic block to reach
the MipsHazardSchedule pass. This patch teaches MipsHazardSchedule to
properly look through such cases.
Reviewers: vkalintiris, zoran.jovanovic
Differential Revision: https://reviews.llvm.org/D27209
llvm-svn: 289529
Only the lower bits of the input element are used. And only the lower element can be undef since the upper bits are zeroed.
Have InstCombineCalls call SimplifyDemandedVectorElts for these intrinsics to reuse this support.
llvm-svn: 289523
Summary:
Since we don't break BBs for function calls. We might get some insane counts
(wrap of unsigned) in the presence of noreturn calls.
This patch sets these counts to zero instead of the wrapped number.
Reviewers: davidxl
Subscribers: xur, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D27602
llvm-svn: 289521
Summary:
This pass will be used to relax instructions which use out of bounds
memory accesses to equivalent operations that can work with the
addresses.
The pass currently implements relaxation for the STDWPtrQRr instruction.
Without this pass, an assertion error would be hit in the pseudo expansion pass.
In the future, we will need to add more instructions to this pass. We can do
that on a case-by-case basic.
Reviewers: arsenm, kparzysz
Subscribers: wdng, llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D27650
llvm-svn: 289517
The general idea here is to get enough of the existing restrictions out of the way that the already existing folding logic in foldMemoryOperand can kick in for STATEPOINTs and fold references to immutable stack slots. The key changes are:
Support for folding multiple operands at once which reference the same load
Support for folding multiple loads into a single instruction
Walk all the operands of the instruction for varidic instructions (this is a bug fix!)
Once this lands, I'll post another patch which refactors the TII interface here. There's nothing actually x86 specific about the x86 code used here.
Differential Revision: https://reviews.llvm.org/D24103
llvm-svn: 289510
The stack slot reuse code had a really amusing bug. We ended up only reusing a stack slot exact once (initial use + reuse) within a basic block. If we had a third statepoint to process, we ended up allocating a new set of stack slots. If we crossed a basic block boundary, the set got cleared. As a result, code which is invoke heavy doesn't see the problem, but multiple calls within a basic block does. Net result: as we optimize invokes into calls, lowering gets worse.
The root error here is that the bitmap uses by the custom allocator wasn't kept in sync. The result was that we ended up resizing the bitmap on the next statepoint (to handle the cross block case), reset the bit once, but then never reset it again.
Differential Revision: https://reviews.llvm.org/D25243
llvm-svn: 289509
Turns out if you were on windows and your default target wasn't windows the system-windows feature wasn't getting enabled.
This fixes that and updates the coff-dwarf test to rely on the new "target-windows" feature. That test was the reason why system-windows was changed to not always be enabled on Windows hosts.
llvm-svn: 289503
These extra specializations were added in the depths of history (r67984 from
2009) and are clearly problematic now. The pointers actually are aligned to the
default (8 bytes), since otherwise UBsan would be complaining loudly.
I *think* it originally made sense because there was no "alignof" to infer the
correct value so the generic case went with what malloc returned (8-byte
aliged objects), and on 32-bit machines this specialization was correct. It
became wrong when we started compiling for 64-bit, and caused a UBSan failure
when we tried to put a ValueHandle into a DenseMap.
Should fix the Green Dragon UBSan bot.
llvm-svn: 289496
Implemented timeouts for Windows using TimerQueueTimers.
Timers are used to supervise the time of execution of the
callback function that is being fuzzed.
Differential Revision: https://reviews.llvm.org/D27237
llvm-svn: 289495
This change enables building builtins for multiple different targets
using LLVM runtimes directory.
To specify the builtin targets to be built, use the LLVM_BUILTIN_TARGETS
variable, where the value is the list of targets. To pass a per target
variable to the builtin build, you can set BUILTINS_<target>_<variable>
where <variable> will be passed to the builtin build for <target>.
Differential Revision: https://reviews.llvm.org/D26652
llvm-svn: 289491
This reverts commit r260386.
These tests all pass for me locally. I have no idea if they will pass on all configurations, so I'll watch the bots closely.
llvm-svn: 289490
incorrect output when LLVM is built with `LLVM_BUILD_LLVM_DYLIB`.
`llvm-config` previously produced output like this
```
$ llvm-config --libfiles
/usr/lib/liblibLLVM-4.0svn.so.so
$ llvm-config --libnames
liblibLLVM-4.0svn.so.so
```
The library prefix and shared library extension were added to
the library name twice which was wrong.
I wanted to write a test cases for this but it looks like **all**
`llvm-config` tests were disabled by r260386 so I'll leave this for
now.
Subscribers: llvm-commits, tstellarAMD
Reviewers: beanz, DiamondLovesYou, axw
Differential Revision: https://reviews.llvm.org/D27393
llvm-svn: 289488
This reverts r289215 (git SHA1 cb7b86a1). It breaks the ubsan build
because a DenseMap that keys off of `AssertingVH<T>` will hit UB when it
tries to cast the empty and tombstone keys to `T *` (due to insufficient
alignment).
This is the relevant stack trace (thanks to Mike Aizatsky):
#0 0x25cf100 in llvm::AssertingVH<llvm::PHINode>::getValPtr() const llvm/include/llvm/IR/ValueHandle.h:212:39
#1 0x25cea20 in llvm::AssertingVH<llvm::PHINode>::operator=(llvm::AssertingVH<llvm::PHINode> const&) llvm/include/llvm/IR/ValueHandle.h:234:19
#2 0x25d0092 in llvm::DenseMapBase<llvm::DenseMap<llvm::AssertingVH<llvm::PHINode>, llvm::detail::DenseSetEmpty, llvm::DenseMapInfo<llvm::AssertingVH<llvm::PHINode> >, llvm::detail::DenseSetPair<llvm::AssertingVH<llvm::PHINode> > >, llvm::AssertingVH<llvm::PHINode>, llvm::detail::DenseSetEmpty, llvm::DenseMapInfo<llvm::AssertingVH<llvm::PHINode> >, llvm::detail::DenseSetPair<llvm::AssertingVH<llvm::PHINode> > >::clear() llvm/include/llvm/ADT/DenseMap.h:113:23
llvm-svn: 289482
Power8 has MTVSRWZ but no LXSIBZX/LXSIHZX, so move 1 or 2 bytes to VSR through MTVSRWZ is much faster than store the extended value into stack and load it with LXSIWZX.
This patch fixes pr31144.
Differential Revision: https://reviews.llvm.org/D27287
llvm-svn: 289473
Summary:
I looked at libgcc's implementation (which is based on the paper,
Software for Doubled-Precision Floating-Point Computations", by Seppo Linnainmaa,
ACM TOMS vol 7 no 3, September 1981, pages 272-283.) and made it generic to
arbitrary IEEE floats.
Differential Revision: https://reviews.llvm.org/D26817
llvm-svn: 289472
This patch ensures the correct minimum bit width during type-shrinking.
Previously when type-shrinking, we always sign-extended values back to their
original width. However, if we are going to sign-extend, and the sign bit is
unknown, we have to increase the minimum bit width by one bit so the
sign-extend will fill the upper bits correctly. If the sign bit is known to be
zero, we can perform a zero-extend instead. This should fix PR31243.
Reference: https://llvm.org/bugs/show_bug.cgi?id=31243
Differential Revision: https://reviews.llvm.org/D27466
llvm-svn: 289470
DWARF specifies that "line 0" really means "no appropriate source
location" in the line table. By default, use this for branch targets
and some other cases that have no specified source location, to
prevent inheriting unfortunate line numbers from physically preceding
instructions (which might be from completely unrelated source).
Updated patch allows enabling or suppressing this behavior for all
unspecified source locations.
Differential Revision: http://reviews.llvm.org/D24180
llvm-svn: 289468
Summary:
I'm planning on changing the way we load metadata to enable laziness.
I'm getting lost in this gigantic files, and gigantic class that is the bitcode
reader. This is a first toward splitting it in a few coarse components that
are more easily understandable.
Reviewers: pcc, tejohnson
Subscribers: mgorny, llvm-commits, dexonsmith
Differential Revision: https://reviews.llvm.org/D27646
llvm-svn: 289461
Summary:
Compiling with GCC 5 or later can fail with a bogus error "constructor
required before non-static data member for
llvm::ValueEnumerator::MDRange::First has been parsed".
This was originally fixed upstream in GCC PR 70528, but later this fix
was reverted, and released versions of GCC still show the bogus error.
To work around this, replace MDRange's declaration of a default
constructor with a definition.
Reviewers: dexonsmith, rsmith, rivanvx
Subscribers: llvm-commits, dim, dexonsmith
Differential Revision: https://reviews.llvm.org/D18730
llvm-svn: 289454
Artur Pilipenko