Make these loops follow GetGEPOperands() behavior.
Let: %q = GEP %p, X, ...
If %p is a GEP, we can chase baseptr further, only if X==0.

llvm-svn: 44999

Fix PR1782, patch by Wojtek Matyjewicz!

llvm-svn: 44733

Rather than having special rules like "intrinsics cannot
throw exceptions", just mark intrinsics with the nounwind
attribute. Likewise, mark intrinsics as readnone/readonly
and get rid of special al

Rather than having special rules like "intrinsics cannot
throw exceptions", just mark intrinsics with the nounwind
attribute. Likewise, mark intrinsics as readnone/readonly
and get rid of special aliasing logic (which didn't use
anything more than this anyway).

llvm-svn: 44544

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Integrate the readonly/readnone logic more deeply
into alias analysis. This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
wh

Integrate the readonly/readnone logic more deeply
into alias analysis. This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
which take a callsite parameter. These should be
used unless the callsite is not known, since in
general they can do a better job than the versions
that take a function. Also, users should no longer
call the version of getModRefBehavior that takes
both a function and a callsite. To reduce the
chance of misuse it is now protected.

llvm-svn: 44487

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Add some convenience methods for querying attributes, and
use them.

llvm-svn: 44403

Fix PR1146: parameter attributes are longer part of
the function type, instead they belong to functions
and function calls. This is an updated and slightly
corrected version of Reid Spencer's origin

Fix PR1146: parameter attributes are longer part of
the function type, instead they belong to functions
and function calls. This is an updated and slightly
corrected version of Reid Spencer's original patch.
The only known problem is that auto-upgrading of
bitcode files doesn't seem to work properly (see
test/Bitcode/AutoUpgradeIntrinsics.ll). Hopefully
a bitcode guru (who might that be? :) ) will fix it.

llvm-svn: 44359

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Ding dong, the DoesntAccessMemoryFns and
OnlyReadsMemoryFns tables are dead! We
get more, and more accurate, information
from gcc via the readnone and readonly
function attributes.

llvm-svn: 44288

Teach alias analysis about readnone/readonly functions.
Based on a patch by Török Edwin.

llvm-svn: 44279

Fix for PR1801

llvm-svn: 44193

Fix PR1774 and BasicAA/2007-11-05-SizeCrash.ll

llvm-svn: 43756

Executive summary: getTypeSize -> getTypeStoreSize / getABITypeSize.
The meaning of getTypeSize was not clear - clarifying it is important
now that we have x86 long double and arbitrary precision int

Executive summary: getTypeSize -> getTypeStoreSize / getABITypeSize.
The meaning of getTypeSize was not clear - clarifying it is important
now that we have x86 long double and arbitrary precision integers.
The issue with long double is that it requires 80 bits, and this is
not a multiple of its alignment. This gives a primitive type for
which getTypeSize differed from getABITypeSize. For arbitrary precision
integers it is even worse: there is the minimum number of bits needed to
hold the type (eg: 36 for an i36), the maximum number of bits that will
be overwriten when storing the type (40 bits for i36) and the ABI size
(i.e. the storage size rounded up to a multiple of the alignment; 64 bits
for i36).

This patch removes getTypeSize (not really - it is still there but
deprecated to allow for a gradual transition). Instead there is:

(1) getTypeSizeInBits - a number of bits that suffices to hold all
values of the type. For a primitive type, this is the minimum number
of bits. For an i36 this is 36 bits. For x86 long double it is 80.
This corresponds to gcc's TYPE_PRECISION.

(2) getTypeStoreSizeInBits - the maximum number of bits that is
written when storing the type (or read when reading it). For an
i36 this is 40 bits, for an x86 long double it is 80 bits. This
is the size alias analysis is interested in (getTypeStoreSize
returns the number of bytes). There doesn't seem to be anything
corresponding to this in gcc.

(3) getABITypeSizeInBits - this is getTypeStoreSizeInBits rounded
up to a multiple of the alignment. For an i36 this is 64, for an
x86 long double this is 96 or 128 depending on the OS. This is the
spacing between consecutive elements when you form an array out of
this type (getABITypeSize returns the number of bytes). This is
TYPE_SIZE in gcc.

Since successive elements in a SequentialType (arrays, pointers
and vectors) need to be aligned, the spacing between them will be
given by getABITypeSize. This means that the size of an array
is the length times the getABITypeSize. It also means that GEP
computations need to use getABITypeSize when computing offsets.
Furthermore, if an alloca allocates several elements at once then
these too need to be aligned, so the size of the alloca has to be
the number of elements multiplied by getABITypeSize. Logically
speaking this doesn't have to be the case when allocating just
one element, but it is simpler to also use getABITypeSize in this
case. So alloca's and mallocs should use getABITypeSize. Finally,
since gcc's only notion of size is that given by getABITypeSize, if
you want to output assembler etc the same as gcc then getABITypeSize
is the size you want.

Since a store will overwrite no more than getTypeStoreSize bytes,
and a read will read no more than that many bytes, this is the
notion of size appropriate for alias analysis calculations.

In this patch I have corrected all type size uses except some of
those in ScalarReplAggregates, lib/Codegen, lib/Target (the hard
cases). I will get around to auditing these too at some point,
but I could do with some help.

Finally, I made one change which I think wise but others might
consider pointless and suboptimal: in an unpacked struct the
amount of space allocated for a field is now given by the ABI
size rather than getTypeStoreSize. I did this because every
other place that reserves memory for a type (eg: alloca) now
uses getABITypeSize, and I didn't want to make an exception
for unpacked structs, i.e. I did it to make things more uniform.
This only effects structs containing long doubles and arbitrary
precision integers. If someone wants to pack these types more
tightly they can always use a packed struct.

llvm-svn: 43620

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Make a comment better.

llvm-svn: 43379

Fix for PR1741.

llvm-svn: 43326

Add lengthof and endof templates that hide a lot of sizeof computations.
Patch by Sterling Stein!

llvm-svn: 41758

Missing break. Patch by Wojciech Matyjewicz.

llvm-svn: 41727

This resolves a regression of BasicAA which failed to find any memory information for overloaded intrinsics (PR1600). This resolves that issue, and improves the matching scheme to use a BitVector rat

This resolves a regression of BasicAA which failed to find any memory information for overloaded intrinsics (PR1600). This resolves that issue, and improves the matching scheme to use a BitVector rather than a binary search.

llvm-svn: 40872

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Upgrade BasicAliasAnalysis::getModRefBehavior to not call Value::getName,
which dynamically allocates the string result. This speeds up dse on the
testcase from PR1432 from 0.3781s to 0.1804s (2.1x)

Upgrade BasicAliasAnalysis::getModRefBehavior to not call Value::getName,
which dynamically allocates the string result. This speeds up dse on the
testcase from PR1432 from 0.3781s to 0.1804s (2.1x).

llvm-svn: 40838

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Implement review feedback.

llvm-svn: 40745

Teach BasicAA about noalias parameter attributes, but do it correctly this time.

llvm-svn: 40711

Revert overly aggressive interpretation of noalias

llvm-svn: 40635

Teach BasicAA about noalias function parameters. Passes all of DejaGNU and test-suite.

llvm-svn: 40624

Fix comments about vectors to use the current wording.

llvm-svn: 39921

Add explicit keywords.

llvm-svn: 37839

Make BasicAliasAnalysis correctly register itself. Patch by Devang

llvm-svn: 37627

Drop 'const'

llvm-svn: 36662