Commit Graph

172 Commits

Author SHA1 Message Date
Ahmed Bougacha
4a2d95826e Add a bunch of CHECK missing colons in tests. NFC.
Some wouldn't pass;  fixed most, the rest will be fixed separately.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232239 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-14 01:43:57 +00:00
David Blaikie
5a70dd1d82 [opaque pointer type] Add textual IR support for explicit type parameter to gep operator
Similar to gep (r230786) and load (r230794) changes.

Similar migration script can be used to update test cases, which
successfully migrated all of LLVM and Polly, but about 4 test cases
needed manually changes in Clang.

(this script will read the contents of stdin and massage it into stdout
- wrap it in the 'apply.sh' script shown in previous commits + xargs to
apply it over a large set of test cases)

import fileinput
import sys
import re

rep = re.compile(r"(getelementptr(?:\s+inbounds)?\s*\()((<\d*\s+x\s+)?([^@]*?)(|\s*addrspace\(\d+\))\s*\*(?(3)>)\s*)(?=$|%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|zeroinitializer|<|\[\[[a-zA-Z]|\{\{)", re.MULTILINE | re.DOTALL)

def conv(match):
  line = match.group(1)
  line += match.group(4)
  line += ", "
  line += match.group(2)
  return line

line = sys.stdin.read()
off = 0
for match in re.finditer(rep, line):
  sys.stdout.write(line[off:match.start()])
  sys.stdout.write(conv(match))
  off = match.end()
sys.stdout.write(line[off:])

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232184 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-13 18:20:45 +00:00
David Blaikie
7c9c6ed761 [opaque pointer type] Add textual IR support for explicit type parameter to load instruction
Essentially the same as the GEP change in r230786.

A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)

import fileinput
import sys
import re

pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")

for line in sys.stdin:
  sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7649

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230794 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 21:17:42 +00:00
David Blaikie
198d8baafb [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction
One of several parallel first steps to remove the target type of pointers,
replacing them with a single opaque pointer type.

This adds an explicit type parameter to the gep instruction so that when the
first parameter becomes an opaque pointer type, the type to gep through is
still available to the instructions.

* This doesn't modify gep operators, only instructions (operators will be
  handled separately)

* Textual IR changes only. Bitcode (including upgrade) and changing the
  in-memory representation will be in separate changes.

* geps of vectors are transformed as:
    getelementptr <4 x float*> %x, ...
  ->getelementptr float, <4 x float*> %x, ...
  Then, once the opaque pointer type is introduced, this will ultimately look
  like:
    getelementptr float, <4 x ptr> %x
  with the unambiguous interpretation that it is a vector of pointers to float.

* address spaces remain on the pointer, not the type:
    getelementptr float addrspace(1)* %x
  ->getelementptr float, float addrspace(1)* %x
  Then, eventually:
    getelementptr float, ptr addrspace(1) %x

Importantly, the massive amount of test case churn has been automated by
same crappy python code. I had to manually update a few test cases that
wouldn't fit the script's model (r228970,r229196,r229197,r229198). The
python script just massages stdin and writes the result to stdout, I
then wrapped that in a shell script to handle replacing files, then
using the usual find+xargs to migrate all the files.

update.py:
import fileinput
import sys
import re

ibrep = re.compile(r"(^.*?[^%\w]getelementptr inbounds )(((?:<\d* x )?)(.*?)(| addrspace\(\d\)) *\*(|>)(?:$| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$))")
normrep = re.compile(       r"(^.*?[^%\w]getelementptr )(((?:<\d* x )?)(.*?)(| addrspace\(\d\)) *\*(|>)(?:$| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$))")

def conv(match, line):
  if not match:
    return line
  line = match.groups()[0]
  if len(match.groups()[5]) == 0:
    line += match.groups()[2]
  line += match.groups()[3]
  line += ", "
  line += match.groups()[1]
  line += "\n"
  return line

for line in sys.stdin:
  if line.find("getelementptr ") == line.find("getelementptr inbounds"):
    if line.find("getelementptr inbounds") != line.find("getelementptr inbounds ("):
      line = conv(re.match(ibrep, line), line)
  elif line.find("getelementptr ") != line.find("getelementptr ("):
    line = conv(re.match(normrep, line), line)
  sys.stdout.write(line)

apply.sh:
for name in "$@"
do
  python3 `dirname "$0"`/update.py < "$name" > "$name.tmp" && mv "$name.tmp" "$name"
  rm -f "$name.tmp"
done

The actual commands:
From llvm/src:
find test/ -name *.ll | xargs ./apply.sh
From llvm/src/tools/clang:
find test/ -name *.mm -o -name *.m -o -name *.cpp -o -name *.c | xargs -I '{}' ../../apply.sh "{}"
From llvm/src/tools/polly:
find test/ -name *.ll | xargs ./apply.sh

After that, check-all (with llvm, clang, clang-tools-extra, lld,
compiler-rt, and polly all checked out).

The extra 'rm' in the apply.sh script is due to a few files in clang's test
suite using interesting unicode stuff that my python script was throwing
exceptions on. None of those files needed to be migrated, so it seemed
sufficient to ignore those cases.

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7636

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230786 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-27 19:29:02 +00:00
Sanjay Patel
d2c64e2df9 Fix really obscure bug in CannotBeNegativeZero() (PR22688)
With a diabolically crafted test case, we could recurse
through this code and return true instead of false.

The larger engineering crime is the use of magic numbers. 
Added FIXME comments for those.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230515 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-25 18:00:15 +00:00
Mehdi Amini
2bd4b63e7a InstSimplify: simplify 0 / X if nnan and nsz
From: Fiona Glaser <fglaser@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230238 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-23 18:30:25 +00:00
David Majnemer
6de0a12927 IR: Properly return nullptr when getAggregateElement is out-of-bounds
We didn't properly handle the out-of-bounds case for
ConstantAggregateZero and UndefValue.  This would manifest as a crash
when the constant folder was asked to fold a load of a constant global
whose struct type has no operands.

This fixes PR22595.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229352 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-16 04:02:09 +00:00
Elena Demikhovsky
b5c82c079a Fold fcmp in cases where value is provably non-negative. By Arch Robison.
This patch folds fcmp in some cases of interest in Julia. The patch adds a function CannotBeOrderedLessThanZero that returns true if a value is provably not less than zero. I.e. the function returns true if the value is provably -0, +0, positive, or a NaN. The patch extends InstructionSimplify.cpp to fold instances of fcmp where:
 - the predicate is olt or uge
 - the first operand is provably not less than zero
 - the second operand is zero
The motivation for handling these cases optimizing away domain checks for sqrt in Julia for common idioms such as sqrt(x*x+y*y)..

http://reviews.llvm.org/D6972



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227298 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-28 08:03:58 +00:00
David Majnemer
9cd99a0724 InstSimplify: Optimize away pointless comparisons
(X & INT_MIN) ? X & INT_MAX : X  into  X & INT_MAX
(X & INT_MIN) ? X : X & INT_MAX  into  X
(X & INT_MIN) ? X | INT_MIN : X  into  X
(X & INT_MIN) ? X : X | INT_MIN  into  X | INT_MIN

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224669 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 03:04:38 +00:00
David Majnemer
73059bd1f1 ConstantFold: Shifting undef by zero results in undef
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224553 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-18 23:54:43 +00:00
David Majnemer
891ec6d69f InstSimplify: shl nsw/nuw undef, %V -> undef
We can always choose an value for undef which might cause %V to shift
out an important bit except for one case, when %V is zero.

However, shl behaves like an identity function when the right hand side
is zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224405 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-17 01:54:33 +00:00
David Majnemer
c57bee5399 InstSimplify: Remove usesless %a parameter from tests
No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224016 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-11 12:56:17 +00:00
David Majnemer
ea9bcfc707 ConstantFold: an undef shift amount results in undef
X shifted by undef results in undef because the undef value can
represent values greater than the width of the operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223968 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 21:38:05 +00:00
David Majnemer
895316336e ConstantFold: div undef, 0 should fold to undef, not zero
Dividing by zero yields an undefined value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223924 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 09:14:55 +00:00
David Majnemer
6578f1beb1 InstSimplify: [al]shr exact undef, %X -> undef
Exact shifts always keep the non-zero bits of their input.  This means
it keeps it's undef bits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223923 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 09:14:52 +00:00
David Majnemer
1297775557 InstSimplify: div %X, 0 -> undef
We already optimized rem %X, 0 to undef, we should do the same for div.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223919 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 07:52:18 +00:00
David Majnemer
fca9c7b21c InstSimplify: Try to bring back the rest of r223583
This reverts r223624 with a small tweak, hopefully this will make stage3
equivalent.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223679 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-08 18:30:43 +00:00
NAKAMURA Takumi
e4a5390406 Revert a part of r223583, for now. It seems causing different emission between stage2(gcc-clang) and stage3 clang. Investigating.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223624 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-08 02:07:22 +00:00
David Majnemer
620e8763ec InstSimplify: Optimize away useless unsigned comparisons
Code like X < Y && Y == 0 should always be folded away to false.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223583 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-06 10:51:40 +00:00
Hal Finkel
efbb95a1be Revert "r223364 - Revert r223347 which has caused crashes on bootstrap bots."
Reapply r223347, with a fix to not crash on uninserted instructions (or more
precisely, instructions in uninserted blocks). bugpoint was able to reduce the
test case somewhat, but it is still somewhat large (and relies on setting
things up to be simplified during inlining), so I've not included it here.
Nevertheless, it is clear what is going on and why.

Original commit message:

Restrict somewhat the memory-allocation pointer cmp opt from r223093

Based on review comments from Richard Smith, restrict this optimization from
applying to globals that might resolve lazily to other dynamically-loaded
modules, and also from dynamic allocas (which might be transformed into malloc
calls). In short, take extra care that the compared-to pointer is really
simultaneously live with the memory allocation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223371 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-04 17:45:19 +00:00
Alexander Potapenko
182d9aaccb Revert r223347 which has caused crashes on bootstrap bots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223364 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-04 14:22:27 +00:00
Hal Finkel
d70d5148a6 Restrict somewhat the memory-allocation pointer cmp opt from r223093
Based on review comments from Richard Smith, restrict this optimization from
applying to globals that might resolve lazily to other dynamically-loaded
modules, and also from dynamic allocas (which might be transformed into malloc
calls). In short, take extra care that the compared-to pointer is really
simultaneously live with the memory allocation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223347 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-04 09:22:28 +00:00
Hal Finkel
7e32aa1015 Simplify pointer comparisons involving memory allocation functions
System memory allocation functions, which are identified at the IR level by the
noalias attribute on the return value, must return a pointer into a memory region
disjoint from any other memory accessible to the caller. We can use this
property to simplify pointer comparisons between allocated memory and local
stack addresses and the addresses of global variables. Neither the stack nor
global variables can overlap with the region used by the memory allocator.

Fixes PR21556.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223093 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 23:38:06 +00:00
David Majnemer
f45536e75e InstSimplify: Restore optimizations lost in r210006
This restores our ability to optimize:
(X & C) ? X & ~C : X  into  X & ~C
(X & C) ? X : X & ~C  into  X
(X & C) ? X | C : X  into  X
(X & C) ? X : X | C  into  X | C

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222868 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-27 06:32:46 +00:00
David Majnemer
044b644f54 InstSimplify: Handle some simple tautological comparisons
This handles cases where we are comparing a masked value against itself.
The analysis could be further improved by making it recursive but such
expense is not currently justified.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222716 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-25 02:55:48 +00:00
David Majnemer
7eca618dfc InstSimplify: Simplify (sub 0, X) -> X if it's NUW
This is a generalization of the X - (0 - Y) -> X transform.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222611 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-22 07:15:16 +00:00
David Majnemer
49c14f54b2 InstSimplify: Exact shifts of X by Y are X if X has the lsb set
Exact shifts may not shift out any non-zero bits. Use computeKnownBits
to determine when this occurs and just return the left hand side.

This fixes PR21477.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221325 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 00:59:59 +00:00
Bruno Cardoso Lopes
5165ff9878 [InstSimplify] Support constant folding to vector of pointers
ConstantFolding crashes when trying to InstSimplify the following load:

@a = private unnamed_addr constant %mst {
     i8* inttoptr (i64 -1 to i8*),
     i8* inttoptr (i64 -1 to i8*)
}, align 8

%x = load <2 x i8*>* bitcast (%mst* @a to <2 x i8*>*), align 8

This patch fix this by adding support to this type of folding:

%x = load <2 x i8*>* bitcast (%mst* @a to <2 x i8*>*), align 8
==> gets folded to:
  %x = <2 x i8*> <i8* inttoptr (i64 -1 to i8*), i8* inttoptr (i64 -1 to i8*)>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220380 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-22 12:18:48 +00:00
David Majnemer
dea8105323 InstCombine: Simplify FoldICmpCstShrCst
This function was complicated by the fact that it tried to perform
canonicalizations that were already preformed by InstSimplify.  Remove
this extra code and move the tests over to InstSimplify.  Add asserts to
make sure our preconditions hold before we make any assumptions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220314 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-21 19:51:55 +00:00
Philip Reames
90f3f15da5 Introduce a 'nonnull' metadata on Load instructions.
The newly introduced 'nonnull' metadata is analogous to existing 'nonnull' attributes, but applies to load instructions rather than call arguments or returns.  Long term, it would be nice to combine these into a single construct.   The value of the load is allowed to vary between successive loads, but null is not a valid value to be loaded by any load marked nonnull.

Reviewed by: Hal Finkel
Differential Revision:  http://reviews.llvm.org/D5220




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220240 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-20 22:40:55 +00:00
Hal Finkel
f0f98417ca Revert "r216914 - Revert: [APFloat] Fixed a bug in method 'fusedMultiplyAdd'"
Reapply r216913, a fix for PR20832 by Andrea Di Biagio. The commit was reverted
because of buildbot failures, and credit goes to Ulrich Weigand for isolating
the underlying issue (which can be confirmed by Valgrind, which does helpfully
light up like the fourth of July). Uli explained the problem with the original
patch as:

  It seems the problem is calling multiplySignificand with an addend of category
  fcZero; that is not expected by this routine.  Note that for fcZero, the
  significand parts are simply uninitialized, but the code in (or rather, called
  from) multiplySignificand will unconditionally access them -- in effect using
  uninitialized contents.

This version avoids using a category == fcZero addend within
multiplySignificand, which avoids this problem (the Valgrind output is also now
clean).

Original commit message:

[APFloat] Fixed a bug in method 'fusedMultiplyAdd'.

When folding a fused multiply-add builtin call, make sure that we propagate the
correct result in the case where the addend is zero, and the two other operands
are finite non-zero.

Example:
  define double @test() {
    %1 = call double @llvm.fma.f64(double 7.0, double 8.0, double 0.0)
    ret double %1
  }

Before this patch, the instruction simplifier wrongly folded the builtin call
in function @test to constant 'double 7.0'.
With this patch, method 'fusedMultiplyAdd' correctly evaluates the multiply and
propagates the expected result (i.e. 56.0).

Added test fold-builtin-fma.ll with the reproducible from PR20832 plus extra
test cases to verify the behavior of method 'fusedMultiplyAdd' in the presence
of NaN/Inf operands.

This fixes PR20832.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219708 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 19:23:07 +00:00
David Majnemer
9043f74acb InstCombine, InstSimplify: (%X /s C1) /s C2 isn't always 0 when C1 * C2 overflow
consider:
C1 = INT_MIN
C2 = -1

C1 * C2 overflows without a doubt but consider the following:
%x = i32 INT_MIN

This means that (%X /s C1) is 1 and (%X /s C1) /s C2 is -1.

N. B.  Move the unsigned version of this transform to InstSimplify, it
doesn't create any new instructions.

This fixes PR21243.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219567 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-11 10:20:01 +00:00
David Majnemer
d5f73530de InstSimplify: Don't allow (x srem y) urem y -> x srem y
Let's consider the case where:
%x i16 = 32768
%y i16 = 384

%x srem %y = 65408
(%x srem %y) urem %y = 128

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217939 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-17 04:16:35 +00:00
David Majnemer
27e656c742 InstSimplify: ((X % Y) % Y) -> (X % Y)
Patch by Sonam Kumari!

Differential Revision: http://reviews.llvm.org/D5350

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217937 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-17 03:34:34 +00:00
David Majnemer
c3e70ca886 InstSimplify: Simplify trivial and/or of icmps
Some ICmpInsts when anded/ored with another ICmpInst trivially reduces
to true or false depending on whether or not all integers or no integers
satisfy the intersected/unioned range.

This sort of trivial looking code can come about when InstCombine
performs a range reduction-type operation on sdiv and the like.

This fixes PR20916.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217750 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 08:15:28 +00:00
Andrea Di Biagio
ca514a41ea Revert: [APFloat] Fixed a bug in method 'fusedMultiplyAdd'.
This reverts revision 216913; the new test added at revision 216913
caused regression failures on a couple of buildbots.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216914 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-02 17:22:49 +00:00
Andrea Di Biagio
0b6ee9fd1c [APFloat] Fixed a bug in method 'fusedMultiplyAdd'.
When folding a fused multiply-add builtin call, make sure that we propagate the
correct result in the case where the addend is zero, and the two other operands
are finite non-zero.

Example:
  define double @test() {
    %1 = call double @llvm.fma.f64(double 7.0, double 8.0, double 0.0)
    ret double %1
  }

Before this patch, the instruction simplifier wrongly folded the builtin call
in function @test to constant 'double 7.0'.
With this patch, method 'fusedMultiplyAdd' correctly evaluates the multiply and
propagates the expected result (i.e. 56.0).

Added test fold-builtin-fma.ll with the reproducible from PR20832 plus extra
test cases to verify the behavior of method 'fusedMultiplyAdd' in the presence
of NaN/Inf operands.

This fixes PR20832.

Differential Revision: http://reviews.llvm.org/D5152


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216913 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-02 16:44:56 +00:00
David Majnemer
b11fff1d8a InstSimplify: Move a transform from InstCombine to InstSimplify
Several combines involving icmp (shl C2, %X) C1 can be simplified
without introducing any new instructions.  Move them to InstSimplify;
while we are at it, make them more powerful.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216642 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-28 03:34:28 +00:00
David Majnemer
48164ed24d InstSimplify: Don't simplify gep X, (Y-X) to Y if types differ
It's incorrect to perform this simplification if the types differ.
A bitcast would need to be inserted for this to work.

This fixes PR20771.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216597 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-27 20:08:34 +00:00
Nico Weber
1c768816d7 Reland r216439 215441, majnemer has a real fix for PR20771.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216586 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-27 20:06:19 +00:00
Nico Weber
b2f71836eb Revert r216439 (and r216441, else the former doesn't revert cleanly).
It caused PR 20771. I'll land a test on the clang side.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216582 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-27 20:00:13 +00:00
David Majnemer
d8e448bd27 InstSimplify: Compute comparison ranges for left shift instructions
'shl nuw CI, x' produces [CI, CI << CLZ(CI)]
'shl nsw CI, x' produces [CI << CLO(CI)-1, CI] if CI is negative
'shl nsw CI, x' produces [CI, CI << CLZ(CI)-1] if CI is non-negative

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216570 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-27 18:03:46 +00:00
David Majnemer
8058ffeb18 InstSimplify: Fold gep X, (sub 0, ptrtoint(X)) to null
Save InstCombine some work if we can perform this fold during
InstSimplify.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216441 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-26 07:08:03 +00:00
David Majnemer
594e4a1dd3 InstSimplify: Simplify trivial pointer expressions like b + (e - b)
consider:
long long *f(long long *b, long long *e) {
  return b + (e - b);
}

we would lower this to something like:
define i64* @f(i64* %b, i64* %e) {
  %1 = ptrtoint i64* %e to i64
  %2 = ptrtoint i64* %b to i64
  %3 = sub i64 %1, %2
  %4 = ashr exact i64 %3, 3
  %5 = getelementptr inbounds i64* %b, i64 %4
  ret i64* %5
}

This should fold away to just 'e'.

N.B.  This adds m_SpecificInt as a convenient way to match against a
particular 64-bit integer when using LLVM's match interface.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216439 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-26 05:55:16 +00:00
David Majnemer
54056f1760 ValueTracking: Figure out more bits when looking at add/sub
Given something like X01XX + X01XX, we know that the result must look
like X1XXX.

Adapted from a patch by Richard Smith, test-case written by me.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216250 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-22 00:40:43 +00:00
David Majnemer
ec7ee07036 InstSimplify: Simplify (X - (0 - Y)) if the second sub is NUW
If the NUW bit is set for 0 - Y, we know that all values for Y other
than 0 would produce a poison value.  This allows us to replace (0 - Y)
with 0 in the expression (X - (0 - Y)) which will ultimately leave us
with X.

This partially fixes PR20189.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214384 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-31 04:49:18 +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
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
Suyog Sarda
c84f22aac5 Move ashr optimization from InstCombineShift to InstSimplify.
Refactor code, no functionality change, test case moved from instcombine to instsimplify.

Differential Revision: http://reviews.llvm.org/D4102
 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213231 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-17 06:28:15 +00:00
David Majnemer
d615588f65 Fix a test broken in r212981
@icmp_sdiv_neg1 should have referred to %a instead of %call, it was
renamed at the last second.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212983 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-14 20:46:04 +00:00