Commit Graph

178 Commits

Author SHA1 Message Date
Manuel Jacob
b5b178a1ed Correct vector type definition in LangRef.
According to VectorType::isValidElementType, any integer, floating point
or pointer type is a valid vector element type.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214302 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-30 12:30:06 +00:00
Dan Liew
e301e0b9a1 Fixed sphinx warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214076 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-28 13:33:51 +00:00
Hal Finkel
8ef7b17dfc Add @llvm.assume, lowering, and some basic properties
This is the first commit in a series that add an @llvm.assume intrinsic which
can be used to provide the optimizer with a condition it may assume to be true
(when the control flow would hit the intrinsic call). Some basic properties are added here:

 - llvm.invariant(true) is dead.
 - llvm.invariant(false) is unreachable (this directly corresponds to the
   documented behavior of MSVC's __assume(0)), so is llvm.invariant(undef).

The intrinsic is tagged as writing arbitrarily, in order to maintain control
dependencies. BasicAA has been updated, however, to return NoModRef for any
particular location-based query so that we don't unnecessarily block code
motion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213973 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-25 21:13:35 +00:00
Hal Finkel
6f5c609076 Simplify and improve scoped-noalias metadata semantics
In the process of fixing the noalias parameter -> metadata conversion process
that will take place during inlining (which will be committed soon, but not
turned on by default), I have come to realize that the semantics provided by
yesterday's commit are not really what we want. Here's why:

void foo(noalias a, noalias b, noalias c, bool x) {
  *q = x ? a : b;
  *c = *q;
}

Generically, we know that *c does not alias with *a and with *b (so there is an
'and' in what we know we're not), and we know that *q might be derived from *a
or from *b (so there is an 'or' in what we know that we are). So we do not want
the semantics currently, where any noalias scope matching any alias.scope
causes a NoAlias return. What we want to know is that the noalias scopes form a
superset of the alias.scope list (meaning that all the things we know we're not
is a superset of all of things the other instruction might be).

Making that change, however, introduces a composibility problem. If we inline
once, adding the noalias metadata, and then inline again adding more, and we
append new scopes onto the noalias and alias.scope lists each time. But, this
means that we could change what was a NoAlias result previously into a MayAlias
result because we appended an additional scope onto one of the alias.scope
lists. So, instead of giving scopes the ability to have parents (which I had
borrowed from the TBAA implementation, but seems increasingly unlikely to be
useful in practice), I've given them domains. The subset/superset condition now
applies within each domain independently, and we only need it to hold in one
domain. Each time we inline, we add the new scopes in a new scope domain, and
everything now composes nicely. In addition, this simplifies the
implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213948 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-25 15:50:02 +00:00
Hal Finkel
16fd27b2c3 Add scoped-noalias metadata
This commit adds scoped noalias metadata. The primary motivations for this
feature are:
  1. To preserve noalias function attribute information when inlining
  2. To provide the ability to model block-scope C99 restrict pointers

Neither of these two abilities are added here, only the necessary
infrastructure. In fact, there should be no change to existing functionality,
only the addition of new features. The logic that converts noalias function
parameters into this metadata during inlining will come in a follow-up commit.

What is added here is the ability to generally specify noalias memory-access
sets. Regarding the metadata, alias-analysis scopes are defined similar to TBAA
nodes:

!scope0 = metadata !{ metadata !"scope of foo()" }
!scope1 = metadata !{ metadata !"scope 1", metadata !scope0 }
!scope2 = metadata !{ metadata !"scope 2", metadata !scope0 }
!scope3 = metadata !{ metadata !"scope 2.1", metadata !scope2 }
!scope4 = metadata !{ metadata !"scope 2.2", metadata !scope2 }

Loads and stores can be tagged with an alias-analysis scope, and also, with a
noalias tag for a specific scope:

... = load %ptr1, !alias.scope !{ !scope1 }
... = load %ptr2, !alias.scope !{ !scope1, !scope2 }, !noalias !{ !scope1 }

When evaluating an aliasing query, if one of the instructions is associated
with an alias.scope id that is identical to the noalias scope associated with
the other instruction, or is a descendant (in the scope hierarchy) of the
noalias scope associated with the other instruction, then the two memory
accesses are assumed not to alias.

Note that is the first element of the scope metadata is a string, then it can
be combined accross functions and translation units. The string can be replaced
by a self-reference to create globally unqiue scope identifiers.

[Note: This overview is slightly stylized, since the metadata nodes really need
to just be numbers (!0 instead of !scope0), and the scope lists are also global
unnamed metadata.]

Existing noalias metadata in a callee is "cloned" for use by the inlined code.
This is necessary because the aliasing scopes are unique to each call site
(because of possible control dependencies on the aliasing properties). For
example, consider a function: foo(noalias a, noalias b) { *a = *b; } that gets
inlined into bar() { ... if (...) foo(a1, b1); ... if (...) foo(a2, b2); } --
now just because we know that a1 does not alias with b1 at the first call site,
and a2 does not alias with b2 at the second call site, we cannot let inlining
these functons have the metadata imply that a1 does not alias with b2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213864 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-24 14:25:39 +00:00
Mark Heffernan
e8d7ebcd5a In unroll pragma syntax and loop hint metadata, change "enable" forms to a new form using the string "full".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213772 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-23 17:31:37 +00:00
Hal Finkel
b3b2aac5be Make use of the align parameter attribute for all pointer arguments
We previously supported the align attribute on all (pointer) parameters, but we
only used it for byval parameters. However, it is completely consistent at the
IR level to treat 'align n' on all pointer parameters as an alignment
assumption on the pointer, and now we wll. Specifically, this causes
computeKnownBits to use the align attribute on all pointer parameters, not just
byval parameters. I've also added an explicit parameter attribute test for this
to test/Bitcode/attributes.ll.

And I've updated the LangRef to document the align parameter attribute (as it
turns out, it was not documented at all previously, although the byval
documentation mentioned that it could be used).

There are (at least) two benefits to doing this:
 - It allows enhancing alignment based on the pointer alignment after inlining callees.
 - It allows simplification of pointer arithmetic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213670 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-22 16:58:55 +00:00
Dan Liew
d883110014 Fix Sphinx warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213660 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-22 14:59:38 +00:00
Mark Heffernan
bc7f1aba2d Rename metadata llvm.loop.vectorize.unroll to llvm.loop.vectorize.interleave.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213588 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-21 23:11:03 +00:00
Mark Heffernan
8ec1546db4 Add loop unrolling metadata descriptions to docs/LangRef.rst.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213397 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-18 19:24:51 +00:00
Hal Finkel
11af4b49b2 Add a dereferenceable attribute
This attribute indicates that the parameter or return pointer is
dereferenceable. Practically speaking, loads from such a pointer within the
associated byte range are safe to speculatively execute. Such pointer
parameters are common in source languages (C++ references, for example).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213385 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-18 15:51:28 +00:00
Tim Northover
3e61ccdded CodeGen: extend f16 conversions to permit types > float.
This makes the two intrinsics @llvm.convert.from.f16 and
@llvm.convert.to.f16 accept types other than simple "float". This is
only strictly needed for the truncate operation, since otherwise
double rounding occurs and there's no way to represent the strict IEEE
conversion. However, for symmetry we allow larger types in the extend
too.

During legalization, we can expand an "fp16_to_double" operation into
two extends for convenience, but abort when the truncate isn't legal. A new
libcall is probably needed here.

Even after this commit, various target tweaks are needed to actually use the
extended intrinsics. I've put these into separate commits for clarity, so there
are no actual tests of f64 conversion here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213248 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-17 10:51:23 +00:00
Hal Finkel
e0fd412fb2 Fix a typo in the inalloca description
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213200 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-16 21:22:46 +00:00
Reid Kleckner
cbebdef6eb Document the maximum LLVM IR alignment, which is 1 << 29 or 0.5 GiB
Add verifier checks.  We already check these in the assembly parser, but
a frontend producing IR in memory wouldn't hit those checks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213027 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-15 01:16:09 +00:00
Matt Arsenault
985d66c081 Fix types in documentation.
The examples were using f32, but the IR type is called float

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212675 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-10 03:22:16 +00:00
Sanjay Patel
d4921230be fixed typos
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212355 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-04 19:40:43 +00:00
Alp Toker
a0d04ac9f1 Fix 'platform-specific' hyphenations
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212056 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-30 18:57:16 +00:00
David Majnemer
c8a1169c93 IR: Add COMDATs to the IR
This new IR facility allows us to represent the object-file semantic of
a COMDAT group.

COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.

This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.

Differential Revision: http://reviews.llvm.org/D4178

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211920 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-27 18:19:56 +00:00
Eli Bendersky
bb167336b3 Rename loop unrolling and loop vectorizer metadata to have a common prefix.
[LLVM part]

These patches rename the loop unrolling and loop vectorizer metadata
such that they have a common 'llvm.loop.' prefix.  Metadata name
changes:

llvm.vectorizer.* => llvm.loop.vectorizer.*
llvm.loopunroll.* => llvm.loop.unroll.*

This was a suggestion from an earlier review
(http://reviews.llvm.org/D4090) which added the loop unrolling
metadata. 

Patch by Mark Heffernan.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211710 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-25 15:41:00 +00:00
Oliver Stannard
e5241cc488 Emit the ARM build attributes ABI_PCS_wchar_t and ABI_enum_size.
Emit the ARM build attributes ABI_PCS_wchar_t and ABI_enum_size based on
module flags metadata.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211349 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-20 10:08:11 +00:00
Jingyue Wu
e4d0a5ec18 [ValueTracking] Extend range metadata to call/invoke
Summary:
With this patch, range metadata can be added to call/invoke including
IntrinsicInst. Previously, it could only be added to load.

Rename computeKnownBitsLoad to computeKnownBitsFromRangeMetadata because
range metadata is not only used by load.

Update the language reference to reflect this change.

Test Plan:
Add several tests in range-2.ll to confirm the verifier is happy with
having range metadata on call/invoke.

Add two tests in AddOverFlow.ll to confirm annotating range metadata to
call/invoke can benefit InstCombine.

Reviewers: meheff, nlewycky, reames, hfinkel, eliben

Reviewed By: eliben

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4187

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211281 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-19 16:50:16 +00:00
Tim Northover
6eaf840a3d Docs: remove extra {} around result types.
It makes the types look like they're single-element structures. And
when we have instructions that *do* result in a struct, that can get
confusing rather quickly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210905 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-13 14:24:23 +00:00
Tim Northover
ab47c159b0 Docs: fix grammar error in description
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210904 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-13 14:24:16 +00:00
Tim Northover
8f2a85e099 IR: add "cmpxchg weak" variant to support permitted failure.
This commit adds a weak variant of the cmpxchg operation, as described
in C++11. A cmpxchg instruction with this modifier is permitted to
fail to store, even if the comparison indicated it should.

As a result, cmpxchg instructions must return a flag indicating
success in addition to their original iN value loaded. Thus, for
uniformity *all* cmpxchg instructions now return "{ iN, i1 }". The
second flag is 1 when the store succeeded.

At the DAG level, a new ATOMIC_CMP_SWAP_WITH_SUCCESS node has been
added as the natural representation for the new cmpxchg instructions.
It is a strong cmpxchg.

By default this gets Expanded to the existing ATOMIC_CMP_SWAP during
Legalization, so existing backends should see no change in behaviour.
If they wish to deal with the enhanced node instead, they can call
setOperationAction on it. Beware: as a node with 2 results, it cannot
be selected from TableGen.

Currently, no use is made of the extra information provided in this
patch. Test updates are almost entirely adapting the input IR to the
new scheme.

Summary for out of tree users:
------------------------------

+ Legacy Bitcode files are upgraded during read.
+ Legacy assembly IR files will be invalid.
+ Front-ends must adapt to different type for "cmpxchg".
+ Backends should be unaffected by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210903 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-13 14:24:07 +00:00
Bob Wilson
4cea00282f LangRef: clarify that global declarations can have section and alignment info.
I'm not sure what it means to set a section for a declaration in another
translation unit, but there are some tests in the tree that do it so it seems
to be legal now regardless.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210819 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-12 20:40:33 +00:00
Bob Wilson
7c3436d941 Add missing "InitializerConstant" to global variable syntax in LangRef.
The syntax for Global Variables in LangRef is missing the initializer.
This syntax section was added in r199218 along with changes to the
dllexport/dllimport handling, and I guess it was just an oversight to omit the
initializer values. I’ve marked the initializer as optional because this syntax
is used for both declarations and definitions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210808 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-12 18:42:55 +00:00
Rafael Espindola
ed7d283ce5 Update langref for unnamed_addr being allowed in aliases.
Thanks to Duncan P. N. Exon Smith and Owen Anderson for noticing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210490 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-09 21:21:33 +00:00
Pekka Jaaskelainen
53b344dcca Slight language tweak from Jonathan Humphreys.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210327 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-06 11:21:44 +00:00
Rafael Espindola
6fd1b8ee48 Allow aliases to be unnamed_addr.
Alias with unnamed_addr were in a strange state. It is stored in GlobalValue,
the language reference talks about "unnamed_addr aliases" but the verifier
was rejecting them.

It seems natural to allow unnamed_addr in aliases:

* It is a property of how it is accessed, not of the data itself.
* It is perfectly possible to write code that depends on the address
of an alias.

This patch then makes unname_addr legal for aliases. One side effect is that
the syntax changes for a corner case: In globals, unnamed_addr is now printed
before the address space.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210302 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-06 01:20:28 +00:00
Tom Roeder
5d0f7af3dc Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute.
It includes a pass that rewrites all indirect calls to jumptable functions to pass through these tables.

This also adds backend support for generating the jump-instruction tables on ARM and X86.
Note that since the jumptable attribute creates a second function pointer for a
function, any function marked with jumptable must also be marked with unnamed_addr.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210280 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-05 19:29:43 +00:00
Rafael Espindola
2d21b25393 Allow alias to point to an arbitrary ConstantExpr.
This  patch changes GlobalAlias to point to an arbitrary ConstantExpr and it is
up to MC (or the system assembler) to decide if that expression is valid or not.

This reduces our ability to diagnose invalid uses and how early we can spot
them, but it also lets us do things like

@test5 = alias inttoptr(i32 sub (i32 ptrtoint (i32* @test2 to i32),
                                 i32 ptrtoint (i32* @bar to i32)) to i32*)

An important implication of this patch is that the notion of aliased global
doesn't exist any more. The alias has to encode the information needed to
access it in its metadata (linkage, visibility, type, etc).

Another consequence to notice is that getSection has to return a "const char *".
It could return a NullTerminatedStringRef if there was such a thing, but when
that was proposed the decision was to just uses "const char*" for that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210062 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-03 02:41:57 +00:00
Rafael Espindola
665d42accf [pr19844] Add thread local mode to aliases.
This matches gcc's behavior. It also seems natural given that aliases
contain other properties that govern how it is accessed (linkage,
visibility, dll storage).

Clang still has to be updated to expose this feature to C.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209759 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-28 18:15:43 +00:00
Reid Kleckner
54ba0dfb55 Wording fix for llvm.global_dtors docs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209687 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-27 21:35:17 +00:00
Rafael Espindola
b84ced649e Fix link.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209640 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-26 21:30:40 +00:00
Tim Northover
29f94c7201 AArch64/ARM64: move ARM64 into AArch64's place
This commit starts with a "git mv ARM64 AArch64" and continues out
from there, renaming the C++ classes, intrinsics, and other
target-local objects for consistency.

"ARM64" test directories are also moved, and tests that began their
life in ARM64 use an arm64 triple, those from AArch64 use an aarch64
triple. Both should be equivalent though.

This finishes the AArch64 merge, and everyone should feel free to
continue committing as normal now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209577 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-24 12:50:23 +00:00
Pekka Jaaskelainen
4f22c980f4 Updated the llvm.mem.parallel_loop_access semantics to include the possibility
to have only some of the loop's memory instructions be annotated and still _help_
the loop carried dependence analysis. 

This was discussed in the llvmdev ML (topic: "parallel loop metadata question").


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209507 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-23 11:35:46 +00:00
Nick Lewycky
fe47ebfad3 Add 'nonnull', a new parameter and return attribute which indicates that the pointer is not null. Instcombine will elide comparisons between these and null. Patch by Luqman Aden!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209185 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-20 01:23:40 +00:00
Reid Kleckner
1ce3088669 Add comdat key field to llvm.global_ctors and llvm.global_dtors
This allows us to put dynamic initializers for weak data into the same
comdat group as the data being initialized.  This is necessary for MSVC
ABI compatibility.  Once we have comdats for guard variables, we can use
the combination to help GlobalOpt fire more often for weak data with
guarded initialization on other platforms.

Reviewers: nlewycky

Differential Revision: http://reviews.llvm.org/D3499

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209015 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-16 20:39:27 +00:00
Hal Finkel
70a83b490e [PowerPC] Add global named register support
Support for the intrinsics that read from and write to global named registers
is added for r1, r2 and r13 (depending on the subtarget).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208509 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-11 19:29:11 +00:00
Duncan P. N. Exon Smith
76c17d324c IR: Don't allow non-default visibility on local linkage
Visibilities of `hidden` and `protected` are meaningless for symbols
with local linkage.

  - Change the assembler to reject non-default visibility on symbols
    with local linkage.

  - Change the bitcode reader to auto-upgrade `hidden` and `protected`
    to `default` when the linkage is local.

  - Update LangRef.

<rdar://problem/16141113>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208263 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-07 22:57:20 +00:00
Renato Golin
22f779d1fd Implememting named register intrinsics
This patch implements the infrastructure to use named register constructs in
programs that need access to specific registers (bare metal, kernels, etc).

So far, only the stack pointer is supported as a technology preview, but as it
is, the intrinsic can already support all non-allocatable registers from any
architecture.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208104 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-06 16:51:25 +00:00
Michael J. Spencer
d4b4f2d340 [IR] Make {extract,insert}element accept an index of any integer type.
Given the following C code llvm currently generates suboptimal code for
x86-64:

__m128 bss4( const __m128 *ptr, size_t i, size_t j )
{
    float f = ptr[i][j];
    return (__m128) { f, f, f, f };
}

=================================================

define <4 x float> @_Z4bss4PKDv4_fmm(<4 x float>* nocapture readonly %ptr, i64 %i, i64 %j) #0 {
  %a1 = getelementptr inbounds <4 x float>* %ptr, i64 %i
  %a2 = load <4 x float>* %a1, align 16, !tbaa !1
  %a3 = trunc i64 %j to i32
  %a4 = extractelement <4 x float> %a2, i32 %a3
  %a5 = insertelement <4 x float> undef, float %a4, i32 0
  %a6 = insertelement <4 x float> %a5, float %a4, i32 1
  %a7 = insertelement <4 x float> %a6, float %a4, i32 2
  %a8 = insertelement <4 x float> %a7, float %a4, i32 3
  ret <4 x float> %a8
}

=================================================

        shlq    $4, %rsi
        addq    %rdi, %rsi
        movslq  %edx, %rax
        vbroadcastss    (%rsi,%rax,4), %xmm0
        retq

=================================================

The movslq is uneeded, but is present because of the trunc to i32 and then
sext back to i64 that the backend adds for vbroadcastss.

We can't remove it because it changes the meaning. The IR that clang
generates is already suboptimal. What clang really should emit is:

  %a4 = extractelement <4 x float> %a2, i64 %j

This patch makes that legal. A separate patch will teach clang to do it.

Differential Revision: http://reviews.llvm.org/D3519

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207801 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-01 22:12:39 +00:00
Reid Kleckner
710c1a449d Add 'musttail' marker to call instructions
This is similar to the 'tail' marker, except that it guarantees that
tail call optimization will occur.  It also comes with convervative IR
verification rules that ensure that tail call optimization is possible.

Reviewers: nicholas

Differential Revision: http://llvm-reviews.chandlerc.com/D3240

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207143 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-24 20:14:34 +00:00
Alp Toker
46d36be2eb Fix some doc and comment typos
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205899 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 14:47:27 +00:00
Sean Silva
0a50cec3cb [docs] Fix up some links to the preferred style.
:doc:`...` and :ref:`...` links help Sphinx keep track the dependencies
between documents and ensure that they are not pointing to nowhere.

Raw HTML links work just fine and are easier for people less familiar
with reST/Sphinx. They are easy to change over to the :doc:/:ref: style
after the fact so this is not a problem.

This commit doesn't fix all of them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205792 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 21:06:22 +00:00
Sean Silva
71e245c1f6 [docs] Fix some Sphinx warnings that have crept in.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205742 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 22:29:53 +00:00
Rafael Espindola
f165cf7ce8 Prevent alias from pointing to weak aliases.
This adds back r204781.

Original message:

Aliases are just another name for a position in a file. As such, the
regular symbol resolutions are not applied. For example, given

define void @my_func() {
  ret void
}
@my_alias = alias weak void ()* @my_func
@my_alias2 = alias void ()* @my_alias

We produce without this patch:

        .weak   my_alias
my_alias = my_func
        .globl  my_alias2
my_alias2 = my_alias

That is, in the resulting ELF file my_alias, my_func and my_alias are
just 3 names pointing to offset 0 of .text. That is *not* the
semantics of IR linking. For example, linking in a

@my_alias = alias void ()* @other_func

would require the strong my_alias to override the weak one and
my_alias2 would end up pointing to other_func.

There is no way to represent that with aliases being just another
name, so the best solution seems to be to just disallow it, converting
a miscompile into an error.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204934 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-27 15:26:56 +00:00
Reid Kleckner
2ce21220d8 inalloca: Fix incorrect example IR and remove LangRef warning
The LangRef warning wasn't formatting the way I intended it to anyway.

Surprisingly inalloca appears to work, even when optimizations are
enabled.  We generate very bad code for it, but we can self-host and run
lots of big tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204888 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-27 01:32:22 +00:00
Joerg Sonnenberger
dd6d74f064 Clarify that select is only non-branching on the IR-level, it often ends
up as jump table or other forms of branches on the machine level.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204819 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-26 15:30:21 +00:00
Joerg Sonnenberger
25d0cfeb29 Clarify llvm.clear_cache description.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204812 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-26 14:35:21 +00:00