Commit Graph

5995 Commits

Author SHA1 Message Date
Chad Rosier
e15b20eb13 [Reassociate] Don't reassociate when mixing regular and fast-math FP
instructions.  Inlining might cause such cases and it's not valid to
reassociate floating-point instructions without the unsafe algebra flag.

Patch by Mehdi Amini <mehdi_amini@apple.com>!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221462 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-06 16:46:37 +00:00
Justin Bogner
03e3dfd20a GCOV: Make sure that function idents in the .gcda and .gcno match
When generating gcov compatible profiling, we sometimes skip emitting
data for functions for one reason or another. However, this was
emitting different function IDs in the .gcno and .gcda files, because
the .gcno case was using the loop index before skipping functions and
the .gcda the array index after. This resulted in completely invalid
gcov data.

This fixes the problem by making the .gcno loop track the ID
separately from the loop index.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221441 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-06 06:55:02 +00:00
NAKAMURA Takumi
090bd82177 llvm/test/Transforms/GCOVProfiling: Avoid to parse backslashes in MDString. Use %/T instead of %T.
LLVM Parser decodes "\bb" as hex in "C:\bb-win7\buildername\build...", with MDString.

See also, http://llvm.org/docs/LangRef.html#metadata-nodes-and-metadata-strings

This reverts r221270, "Disable 3 tests in llvm/test/Transforms/GCOVProfiling/ for now. Investigating."

FIXME: Please check EC in GCOVProfiler::emitProfileNotes().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221334 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-05 06:29:05 +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
David Majnemer
3839fd16a1 Analysis: Make isSafeToSpeculativelyExecute fire less for divides
Divides and remainder operations do not behave like other operations
when they are given poison: they turn into undefined behavior.

It's really hard to know if the operands going into a div are or are not
poison.  Because of this, we should only choose to speculate if there
are constant operands which we can easily reason about.

This fixes PR21412.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221318 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 23:49:08 +00:00
Reid Kleckner
11e6e005b7 Revert "[Reassociate] Canonicalize negative constants out of expressions."
This reverts commit r221171.

It performs this invalid transformation:
-  %div.i = urem i64 -1, %add
-  %sub.i = sub i64 -2, %div.i
+  %div.i = urem i64 1, %add
+  %sub.i1 = add i64 %div.i, -2

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221317 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 23:42:45 +00:00
NAKAMURA Takumi
58cb7beb66 Disable 3 tests in llvm/test/Transforms/GCOVProfiling/ for now. Investigating.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221270 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 14:41:53 +00:00
NAKAMURA Takumi
76614e7991 Remove "REQUIRES:shell" from tests. They work for me.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221269 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 13:41:33 +00:00
NAKAMURA Takumi
992662c0ad llvm/test/Transforms/GCOVProfiling/linezero.ll: Use %/T instead of %T in regex. This works on win32.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221262 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 13:00:48 +00:00
David Majnemer
229e959cd6 Minimize test case further
No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221237 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 05:17:58 +00:00
Reid Kleckner
9d18e626cc Revert "Transforms: reapply SVN r219899"
This reverts commit r220811 and r220839. It made an incorrect change to
musttail handling.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221226 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 02:02:14 +00:00
Hal Finkel
cd9acde7f3 Use AA in LoadCombine
LoadCombine can be smarter about aborting when a writing instruction is
encountered, instead of aborting upon encountering any writing instruction, use
an AliasSetTracker, and only abort when encountering some write that might
alias with the loads that could potentially be combined.

This was originally motivated by comments made (and a test case provided) by
David Majnemer in response to PR21448. It turned out that LoadCombine was not
responsible for that PR, but LoadCombine should also be improved so that
unrelated stores (and @llvm.assume) don't interrupt load combining.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221203 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 23:19:16 +00:00
David Majnemer
c671375e8e InstCombine: Remove infinite loop caused by FoldOpIntoPhi
FoldOpIntoPhi could create an infinite loop if the PHI could potentially
reach a BB it was considering inserting instructions into.  The
instructions it would insert would eventually lead to other combines
firing which would, again, lead to FoldOpIntoPhi firing.

The solution is to handicap FoldOpIntoPhi so that it doesn't attempt to
insert instructions that the PHI might reach.

This fixes PR21377.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221187 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 21:55:12 +00:00
Hal Finkel
f16d6b1ff1 EarlyCSE should ignore calls to @llvm.assume
EarlyCSE uses a simple generation scheme for handling memory-based
dependencies, and calls to @llvm.assume (which are marked as writing to memory
to ensure the preservation of control dependencies) disturb that scheme
unnecessarily. Skipping calls to @llvm.assume is legal, and the alternative
(adding AA calls in EarlyCSE) is likely undesirable (we have GVN for that).

Fixes PR21448.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221175 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 20:21:32 +00:00
Chad Rosier
3f4e9cb609 [Reassociate] Canonicalize negative constants out of expressions.
This gives CSE/GVN more options to eliminate duplicate expressions.
This is a follow up patch to http://reviews.llvm.org/D4904.

http://reviews.llvm.org/D5363

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221171 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 19:11:30 +00:00
Paul Robinson
c3e82bf9f5 Normally an 'optnone' function goes through fast-isel, which does not
call DAGCombiner. But we ran into a case (on Windows) where the
calling convention causes argument lowering to bail out of fast-isel,
and we end up in CodeGenAndEmitDAG() which does run DAGCombiner.
So, we need to make DAGCombiner check for 'optnone' after all.

Commit includes the test that found this, plus another one that got
missed in the original optnone work.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221168 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 18:19:26 +00:00
David Majnemer
9808f11b09 InstCombine: Combine (X | Y) - X to (~X & Y)
This implements the transformation from (X | Y) - X to (~X & Y).

Differential Revision: http://reviews.llvm.org/D5791

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221129 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-03 05:53:55 +00:00
Elena Demikhovsky
01d89eee39 Use Alias Analysis to hoist 2 loads from diamond to the common predecessor basic block.
Alias Analysis allows to detect real barriers for load hoisting.

Review in http://reviews.llvm.org/D5991



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221091 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-02 08:03:05 +00:00
David Majnemer
ed297abb0a InstCombine: Don't assume that m_ZExt matches an Instruction
m_ZExt might bind against a ConstantExpr instead of an Instruction.
Assuming this, using cast<Instruction>, results in InstCombine crashing.

Instead, introduce ZExtOperator to bridge both Instruction and
ConstantExpr ZExts.

This fixes PR21445.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221069 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-01 23:46:05 +00:00
David Majnemer
f74443e53a InstCombine: Combine (X+cst) < 0 --> X < -cst
This can happen pretty often in code that looks like:
int foo = bar - 1;
if (foo < 0)
  do stuff

In this case, bar < 1 is an equivalent condition.

This transform requires that the add instruction be annotated with nsw.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221045 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-01 09:09:51 +00:00
Michael Zolotukhin
cf19403e39 Correctly update dom-tree after loop vectorizer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221009 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-31 22:28:03 +00:00
Bradley Smith
8cff277de2 [SCEV] Improve Scalar Evolution's use of no {un,}signed wrap flags
In a case where we have a no {un,}signed wrap flag on the increment, if
RHS - Start is constant then we can avoid inserting a max operation bewteen
the two, since we can statically determine which is greater.

This allows us to unroll loops such as:

 void testcase3(int v) {
   for (int i=v; i<=v+1; ++i)
     f(i);
 }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220960 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-31 11:40:32 +00:00
NAKAMURA Takumi
7f3bcd623e llvm/test/Transforms/SampleProfile/syntax.ll: Relax MISSING-FILE not to
check locale-aware message catalog.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220934 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-30 22:28:46 +00:00
Philip Reames
aad4ea476e Add handling for range metadata in ValueTracking isKnownNonZero
If we load from a location with range metadata, we can use information about the ranges of the loaded value for optimization purposes.  This helps to remove redundant checks and canonicalize checks for other optimization passes.  This particular patch checks whether a value is known to be non-zero from the range metadata.

Currently, these tests are against InstCombine.  In theory, all of these should be InstSimplify since we're not inserting any new instructions.  Moving the code may follow in a separate change.

Reviewed by: Hal
Differential Revision: http://reviews.llvm.org/D5947



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220925 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-30 20:25:19 +00:00
Diego Novillo
e75c2b3e54 Add profile writing capabilities for sampling profiles.
Summary:
This patch finishes up support for handling sampling profiles in both
text and binary formats. The new binary format uses uleb128 encoding to
represent numeric values. This makes profiles files about 25% smaller.

The profile writer class can write profiles in the existing text and the
new binary format. In subsequent patches, I will add the capability to
read (and perhaps write) profiles in the gcov format used by GCC.

Additionally, I will be adding support in llvm-profdata to manipulate
sampling profiles.

There was a bit of refactoring needed to separate some code that was in
the reader files, but is actually common to both the reader and writer.

The new test checks that reading the same profile encoded as text or
raw, produces the same results.

Reviewers: bogner, dexonsmith

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6000

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220915 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-30 18:00:06 +00:00
NAKAMURA Takumi
8a32713617 llvm/test/Transforms/LoopRotate/nosimplifylatch.ll: Fix possibly mis-repeatedly-pasted test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220880 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-29 23:05:12 +00:00
Yi Jiang
973a76f9ce Test Case for r220872:Do not simplifyLatch for loops where hoisting increments couldresult in extra live range interferance
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220873 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-29 20:20:33 +00:00
Yi Jiang
a5ca5d9f82 Do not simplifyLatch for loops where hoisting increments couldresult in extra live range interferance
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220872 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-29 20:19:47 +00:00
Saleem Abdulrasool
674effc8bd test: tweak inlined-allocs test
Remove pointless checks for storage of uninteresting values.  Ensure that we
perform basic alias analysis to make the test more correct.  Finally, apply a
stylistic change to the test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220839 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-29 06:31:11 +00:00
Saleem Abdulrasool
586cf3d88d Transforms: reapply SVN r219899
This restores the commit from SVN r219899 with an additional change to ensure
that the CodeGen is correct for the case that was identified as being incorrect
(originally PR7272).

In the case that during inlining we need to synthesize a value on the stack
(i.e. for passing a value byval), then any function involving that alloca must
be stripped of its tailness as the restriction that it does not access the
parent's stack no longer holds.  Unfortunately, a single alloca can cause a
rippling effect through out the inlining as the value may be aliased or may be
mutated through an escaped external call.  As such, we simply track if an alloca
has been introduced in the frame during inlining, and strip any tail calls.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220811 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-28 18:27:37 +00:00
David Majnemer
fe58be3733 InstCombine: Fix a combine assuming that icmp operands were integers
An icmp may have pointer arguments, it isn't limited to integers or
vectors of integers.

This fixes PR21388.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220664 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-27 05:47:49 +00:00
Jingyue Wu
71fe4f0197 [SeparateConstOffsetFromGEP] Fixed a bug related to unsigned modulo
The dividend in "signed % unsigned" is treated as unsigned instead of signed,
causing unexpected behavior such as -64 % (uint64_t)24 == 0.

Added a regression test in split-gep.ll

Patched by Hao Liu.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220618 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-25 18:34:03 +00:00
Jingyue Wu
5c50ab84b3 [SeparateConstOffsetFromGEP] Fixed a bug in rebuilding OR expressions
The two operands of the new OR expression should be NextInChain and TheOther
instead of the two original operands.

Added a regression test in split-gep.ll.

Hao Liu reported this bug, and provded the test case and an initial patch.
Thanks! 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220615 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-25 17:36:21 +00:00
Sanjay Patel
d2153694e0 Handle sqrt() shrinking in SimplifyLibCalls like any other call
This patch removes a chunk of special case logic for folding 
(float)sqrt((double)x) -> sqrtf(x)
in InstCombineCasts and handles it in the mainstream path of SimplifyLibCalls.

No functional change intended, but I loosened the restriction on the existing
sqrt testcases to allow for this optimization even without unsafe-fp-math because
that's the existing behavior.

I also added a missing test case for not shrinking the llvm.sqrt.f64 intrinsic
in case the result is used as a double.

Differential Revision: http://reviews.llvm.org/D5919



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220514 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-23 21:52:45 +00:00
Justin Bogner
6a369dbdd6 test: Make this test runnable in directories with @ in their names
Jenkins likes to use directories with names involving the '@'
character, which breaks the sed expression in this test. Switch to use
'|' on the assumption that it's less likely to show up in a path.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220401 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-22 18:18:54 +00:00
Sanjay Patel
dc18ebc4b1 Shrinkify libcalls: use float versions of double libm functions with fast-math (bug 17850)
When a call to a double-precision libm function has fast-math semantics 
(via function attribute for now because there is no IR-level FMF on calls), 
we can avoid fpext/fptrunc operations and use the float version of the call
if the input and output are both float.

We already do this optimization using a command-line option; this patch just
adds the ability for fast-math to use the existing functionality.

I moved the cl::opt from InstructionCombining into SimplifyLibCalls because
it's only ever used internally to that class.

Modified the existing test cases to use the unsafe-fp-math attribute rather
than repeating all tests.

This patch should solve: http://llvm.org/bugs/show_bug.cgi?id=17850

Differential Revision: http://reviews.llvm.org/D5893



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220390 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-22 15:29:23 +00:00
Diego Novillo
79ca2c234d Change error to warning when a profile cannot be found.
When the profile for a function cannot be applied, we use to emit an
error. This seems extreme. The compiler can continue, it's just that the
optimization opportunities won't include profile information.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220386 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-22 13:36:35 +00:00
Diego Novillo
418d0cf1c1 Support using sample profiles with partial debug info.
Summary:
When using a profile, we used to require the use -gmlt so that we could
get access to the line locations. This is used to match line numbers in
the input profile to the line numbers in the function's IR.

But this is actually not necessary. The driver can provide source
location tracking without the emission of debug information. In these
cases, the annotation 'llvm.dbg.cu' is missing from the IR, but the
actual line location annotations are still present.

This patch adds a new way of looking for the start of the current
function. Instead of looking through the compile units in llvm.dbg.cu,
we can walk up the scope for the first instruction in the function with
a debug loc. If that describes the function, we use it. Otherwise, we
keep looking until we find one.

If no such instruction is found, we then give up and produce an error.

Reviewers: echristo, dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5887

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220382 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-22 12:59:00 +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
Hans Wennborg
ec4e924836 Revert "Teach the load analysis to allow finding available values which require" (r220277)
This seems to have caused PR21330.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220349 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-21 23:49:52 +00:00
Matt Arsenault
252134602f Add minnum / maxnum intrinsics
These are named following the IEEE-754 names for these
functions, rather than the libm fmin / fmax to avoid
possible ambiguities. Some languages may implement something
resembling fmin / fmax which return NaN if either operand is
to propagate errors. These implement the IEEE-754 semantics
of returning the other operand if either is a NaN representing
missing data.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220341 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-21 23:00:20 +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
Chandler Carruth
9156c5e3ba Teach the load analysis to allow finding available values which require
inttoptr or ptrtoint cast provided there is datalayout available.
Eventually, the datalayout can just be required but in practice it will
always be there today.

To go with the ability to expose available values requiring a ptrtoint
or inttoptr cast, helpers are added to perform one of these three casts.

These smarts are necessary to finish canonicalizing loads and stores to
the operational type requirements without regressing fundamental
combines.

I've added some test cases. These should actually improve as the load
combining and store combining improves, but they may fundamentally be
highlighting some missing combines for select in addition to exercising
the specific added logic to load analysis.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220277 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-21 09:00:40 +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
Chandler Carruth
3ac929c473 Fix a miscompile introduced in r220178.
The original code had an implicit assumption that if the test for
allocas or globals was reached, the two pointers were not equal. With my
changes to make the pointer analysis more powerful here, I also had to
guard against circumstances where the results weren't useful. That in
turn violated the assumption and gave rise to a circumstance in which we
could have a store with both the queried pointer and stored pointer
rooted at *the same* alloca. Clearly, we cannot ignore such a store.
There are other things we might do in this code to better handle the
case of both pointers ending up at the same alloca or global, but it
seems best to at least make the test explicit in what it intends to
check.

I've added tests for both the alloca and global case here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220190 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-20 10:03:01 +00:00
Chandler Carruth
080dfb5bda Fix a somewhat subtle pair of issues with JumpThreading I introduced in
r220178. First, the creation routine doesn't insert prior to the
terminator of the basic block provided, but really at the end of the
basic block. Instead, get the terminator and insert before that. The
next issue was that we need to ensure multiple PHI node entries for
a single predecessor re-use the same cast instruction rather than
creating new ones.

All of the logic here was without tests previously. I've reduced and
added a test case from the test suite that crashed without both of these
fixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220186 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-20 05:34:36 +00:00
Chandler Carruth
35c4e071be Teach the load analysis driving core instcombine logic and other bits of
logic to look through pointer casts, making them trivially stronger in
the face of loads and stores with intervening pointer casts.

I've included a few test cases that demonstrate the kind of folding
instcombine can do without pointer casts and then variations which
obfuscate the logic through bitcasts. Without this patch, the variations
all fail to optimize fully.

This is more important now than it has been in the past as I've started
moving the load canonicialization to more closely follow the value type
requirements rather than the pointer type requirements and thus this
needs to be prepared for more pointer casts. When I made the same change
to stores several test cases regressed without logic along these lines
so I wanted to systematically improve matters first.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220178 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-20 00:24:14 +00:00
Chandler Carruth
fc1c1ec435 Add a datalayout string to this test so that it exercises the full gamut
of InstCombine rather than just the bits enabled when datalayout is
optional.

The primary fixes here are because now things are little endian.

In good news, silliness like this seems like it will be going away as
we've got pretty stong consensus on dropping optional datalayout
entirely.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220176 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-20 00:11:31 +00:00
Chandler Carruth
63276ccdbd Do a better and more complete job of preserving metadata when combining
loads.

This handles many more cases than just the AA metadata, some of them
suggested by Hal in his review of the AA metadata handling patch. I've
tried to test this behavior where tractable to do so.

I'll point out that I have specifically *not* included a test for
debuginfo because it was going to require 2 or 3 times as much work to
craft some input which would survive the "helpful" stripping of debug
info metadata that doesn't match the desired schema. This is another
good example of why the current state of write-ability for our debug
info metadata is unacceptable. I spent over 30 minutes trying to conjure
some test case that would survive, even copying from other debug info
tests, but it always failed to survive with no explanation of why or how
I might fix it. =[

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220165 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-19 10:46:46 +00:00
Chandler Carruth
4d2a706176 Move previously dead code to handle computing the known bits of an alias
up to where it actually works as intended. The problem is that
a GlobalAlias isa GlobalValue and so the prior block handled all of the
cases.

This allows us to constant fold based on the actual constant expression
in the global alias. As an example, see the last function in the newly
added test case which explicitly aligns an unaligned pointer using
constant expression math. Without this change, we fail to see that and
fold an alignment test to zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220164 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-19 09:06:56 +00:00