The motivating example is this
for (j = n; j > 1; j = i) {
i = j / 2;
}
The signed division is safely to be changed to an unsigned division (j is known
to be larger than 1 from the loop guard) and later turned into a single shift
without considering the sign bit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263406 91177308-0d34-0410-b5e6-96231b3b80d8
This reapplies r263258, which was reverted in r263321 because
of issues on Clang side.
From: Mehdi Amini <mehdi.amini@apple.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263393 91177308-0d34-0410-b5e6-96231b3b80d8
For cases where we are truncating an integer vector arithmetic result, it may be better to pre-truncate the input operands - no code to support this yet (scalar is done with SimplifyDemandedBits but adding vector support could be a lot of work) but these tests represent the current codegen status.
Example bugs: PR14666, PR22703
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263384 91177308-0d34-0410-b5e6-96231b3b80d8
The SSE41 v8i16 shift lowering using (v)pblendvb is great for non-constant shift amounts, but if it is constant then we can efficiently reduce the VSELECT to shuffles with the pre-SSE41 lowering.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263383 91177308-0d34-0410-b5e6-96231b3b80d8
Fundamentally, the length of a variable or function name is bound by the
maximum size of a record: 0xffff. However, the name doesn't live in a
vacuum; other data is associated with the name, lowering the bound
further.
We would naively attempt to emit the name, causing us to assert because
the record would no-longer fit in 16-bits. Instead, truncate the name
but preserve as much as we can.
While I have tested this locally, I've decided to not commit it due to
the test's size.
N.B. While this behavior is undesirable, it is better than MSVC's
behavior. They seem to truncate to ~4000 characters.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263378 91177308-0d34-0410-b5e6-96231b3b80d8
It had a weird artificial limitation on the write side: the comdat name
couldn't be bigger than 2**16. However, the reader had no such
limitation. Make the reader and the writer agree.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263377 91177308-0d34-0410-b5e6-96231b3b80d8
Check to see if all operands are constant before calling simplify on them
so that we don't perform wasted simplifications.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263374 91177308-0d34-0410-b5e6-96231b3b80d8
This follows up on the related AVX instruction transforms, but this
one is too strange to do anything more with. Intel's behavioral
description of this instruction in its Software Developer's Manual
is tragi-comic.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263340 91177308-0d34-0410-b5e6-96231b3b80d8
This patch corresponds to review:
http://reviews.llvm.org/D17712
We were not clearing the TOC vector in PPCAsmPrinter when initializing it. This
caused duplicate definition asserts when the pass is reused on the module
(i.e. with -compile-twice or in JIT contexts).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263338 91177308-0d34-0410-b5e6-96231b3b80d8
This lets us for example start running the unit test suite early. For
'check-llvm' on my machine, this drops the tim e from 44s to 32s!!!!!
It's pretty ugly. I barely know how to write Python, so feel free to
just tell me how I should write it instead. =D Thanks to Filipe and
others for help.
Differential Revision: http://reviews.llvm.org/D18089
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cmpxchg[8|16]b uses RBX as one of its argument.
In other words, using this instruction clobbers RBX as it is defined to hold one
the input. When the backend uses dynamically allocated stack, RBX is used as a
reserved register for the base pointer.
Reserved registers have special semantic that only the target understands and
enforces, because of that, the register allocator don’t use them, but also,
don’t try to make sure they are used properly (remember it does not know how
they are supposed to be used).
Therefore, when RBX is used as a reserved register but defined by something that
is not compatible with that use, the register allocator will not fix the
surrounding code to make sure it gets saved and restored properly around the
broken code. This is the responsibility of the target to do the right thing with
its reserved register.
To fix that, when the base pointer needs to be preserved, we use a different
pseudo instruction for cmpxchg that save rbx.
That pseudo takes two more arguments than the regular instruction:
- One is the value to be copied into RBX to set the proper value for the
comparison.
- The other is the virtual register holding the save of the value of RBX as the
base pointer. This saving is done as part of isel (i.e., we emit a copy from
rbx).
cmpxchg_save_rbx <regular cmpxchg args>, input_for_rbx_reg, save_of_rbx_as_bp
This gets expanded into:
rbx = copy input_for_rbx_reg
cmpxchg <regular cmpxchg args>
rbx = save_of_rbx_as_bp
Note: The actual modeling of the pseudo is a bit more complicated to make sure
the interferes that appears after the pseudo gets expanded are properly modeled
before that expansion.
This fixes PR26883.
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commit ae14bf6488e8441f0f6d74f00455555f6f3943ac
Author: Mehdi Amini <mehdi.amini@apple.com>
Date: Fri Mar 11 17:15:50 2016 +0000
Remove PreserveNames template parameter from IRBuilder
Summary:
Following r263086, we are now relying on a flag on the Context to
discard Value names in release builds.
Reviewers: chandlerc
Subscribers: mzolotukhin, llvm-commits
Differential Revision: http://reviews.llvm.org/D18023
From: Mehdi Amini <mehdi.amini@apple.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263258
91177308-0d34-0410-b5e6-96231b3b80d8
until we can figure out what to do about clang and Release build testing.
This reverts commit 263258.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263321 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: As we now have unit-tests for UnrollAnalyzer, we can convert some existing tests to this format. It should make the tests more robust.
Reviewers: chandlerc, sanjoy
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D17904
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263318 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Caller can provides the list of .so files where some files are
unreadable (e.g linux-vdso.so.1). It's more convenient to handler this in
sancov with warning then making all callers to check files.
Reviewers: aizatsky
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D18103
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263307 91177308-0d34-0410-b5e6-96231b3b80d8
Improve vector extension of vectors on hardware without dedicated VSEXT/VZEXT instructions.
We already convert these to SIGN_EXTEND_VECTOR_INREG/ZERO_EXTEND_VECTOR_INREG but can further improve this by using the legalizer instead of prematurely splitting into legal vectors in the combine as this only properly helps for lowering to VSEXT/VZEXT.
Removes a lot of unnecessary any_extend + mask pattern - (Fix for PR25718).
Differential Revision: http://reviews.llvm.org/D17932
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263303 91177308-0d34-0410-b5e6-96231b3b80d8
Instead, extend f16 (like we do when lowering a standalone SETCC),
and let f128 be legalized to the RT calls.
Fixes PR26803.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263301 91177308-0d34-0410-b5e6-96231b3b80d8
