Commit Graph

11959 Commits

Author SHA1 Message Date
Chandler Carruth
68ca48cd90 [SROA] Switch the common variable name for the 'AllocaSlices' class to
'AS'.

Using 'S' as this was a terrible idea. Arguably, 'AS' is not much
better, but it at least follows the idea of using initialisms and
removes active confusion about the AllocaSlices variable and a Slice
variable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219963 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 21:11:55 +00:00
Chandler Carruth
c62c42b1e4 [SROA] More range-based cleanups to SROA, these brought to you by
clang-modernize.

I did have to clean up the variable types and whitespace a bit because
the use of auto made the code much less readable here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219962 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 21:05:14 +00:00
Chandler Carruth
5269b24da1 [SROA] Switch a couple of overly complex iterator accessors to just be
ArrayRef accessors.

I think this even came up in review that this was over-engineered, and
indeed it was. Time to un-build it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219958 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 20:42:08 +00:00
Chandler Carruth
c2320545bc [SROA] Start more deeply moving SROA to use ranges rather than just
iterators.

There are a ton of places where it essentially wants ranges
rather than just iterators. This is just the first step that adds the
core slice range typedefs and uses them in a couple of places. I still
have to explicitly construct them because they've not been punched
throughout the entire set of code. More range-based cleanups incoming.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219955 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 20:24:07 +00:00
Bjorn Steinbrink
6eaa62af77 Allow call-slop optzn for destinations with a suitable dereferenceable attribute
Summary:
Currently, call slot optimization requires that if the destination is an
argument, the argument has the sret attribute. This is to ensure that
the memory access won't trap. In addition to sret, we can also allow the
optimization to happen for arguments that have the new dereferenceable
attribute, which gives the same guarantee.

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5832

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219950 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 19:43:08 +00:00
Sanjay Patel
d8214db086 fold: sqrt(x * x * y) -> fabs(x) * sqrt(y)
If a square root call has an FP multiplication argument that can be reassociated,
then we can hoist a repeated factor out of the square root call and into a fabs().

In the simplest case, this:

   y = sqrt(x * x);

becomes this:

   y = fabs(x);

This patch relies on an earlier optimization in instcombine or reassociate to put the
multiplication tree into a canonical form, so we don't have to search over
every permutation of the multiplication tree.

Because there are no IR-level FastMathFlags for intrinsics (PR21290), we have to
use function-level attributes to do this optimization. This needs to be fixed
for both the intrinsics and in the backend.

Differential Revision: http://reviews.llvm.org/D5787



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219944 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 18:48:17 +00:00
Akira Hatanaka
4eb03123df Reapply r219832 - InstCombine: Narrow switch instructions using known bits.
The code committed in r219832 asserted when it attempted to shrink a switch
statement whose type was larger than 64-bit.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219902 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 06:00:46 +00:00
Saleem Abdulrasool
ebe6584c32 TRE: make TRE a bit more aggressive
Make tail recursion elimination a bit more aggressive.  This allows us to get
tail recursion on functions that are just branches to a different function.  The
fact that the function takes a byval argument does not restrict it from being
optimised into just a tail call.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219899 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 03:27:30 +00:00
Akira Hatanaka
608d59f535 Revert r219832.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219884 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 01:17:02 +00:00
Hal Finkel
43141a0764 Preserve non-byval pointer alignment attributes using @llvm.assume when inlining
For pointer-typed function arguments, enhanced alignment can be asserted using
the 'align' attribute. When inlining, if this enhanced alignment information is
not otherwise available, preserve it using @llvm.assume-based alignment
assumptions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219876 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 23:44:41 +00:00
Chris Bieneman
aaf36b40cc Fixing the build failure due to compiler warnings and unnecessary disambiguation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219861 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 23:11:35 +00:00
Chris Bieneman
c14fb89680 Defining a new API for debug options that doesn't rely on static global cl::opts.
Summary:
This is based on the discussions from the LLVMDev thread:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-August/075886.html

Reviewers: chandlerc

Reviewed By: chandlerc

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5389

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219854 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 21:54:35 +00:00
Akira Hatanaka
38537634e2 InstCombine: Narrow switch instructions using known bits.
Truncate the operands of a switch instruction to a narrower type if the upper
bits are known to be all ones or zeros.

rdar://problem/17720004


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219832 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 19:05:50 +00:00
Hal Finkel
6c15862fd3 [SLPVectorize] Basic ephemeral-value awareness
The SLP vectorizer should not vectorize ephemeral values. These are used to
express information to the optimizer, and vectorizing them does not lead to
faster code (because the ephemeral values are dropped prior to code generation,
vectorized or not), and obscures the information the instructions are
attempting to communicate (the logic that interprets the arguments to
@llvm.assume generically does not understand vectorized conditions).

Also, uses by ephemeral values are free (because they, and the necessary
extractelement instructions, will be dropped prior to code generation).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219816 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-15 17:35:01 +00:00
Eric Christopher
2ff93bfec6 No need to cache this unused variable.
Patch by Ehsan Akhgari.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219749 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 23:58:51 +00:00
Hal Finkel
75277b9f70 [LoopVectorize] Ignore @llvm.assume for cost estimates and legality
A few minor changes to prevent @llvm.assume from interfering with loop
vectorization. First, treat @llvm.assume like the lifetime intrinsics, which
are scalarized (but don't otherwise interfere with the legality checking).
Second, ignore the cost of ephemeral instructions in the loop (these will go
away anyway during CodeGen).

Alignment assumptions and other uses of @llvm.assume can often end up inside of
loops that should be vectorized (this is not uncommon for assumptions generated
by __attribute__((align_value(n))), for example).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219741 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 22:59:49 +00:00
Sanjay Patel
3f349b2ba8 Optimize away fabs() calls when input is squared (known positive).
Eliminate library calls and intrinsic calls to fabs when the input 
is a squared value.

Note that no unsafe-math / fast-math assumptions are needed for
this optimization.

Differential Revision: http://reviews.llvm.org/D5777



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219717 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 20:43:11 +00:00
David Majnemer
505187a9bd InstCombine: Don't miscompile X % ((Pow2 << A) >>u B)
We assumed that A must be greater than B because the right hand side of
a remainder operator must be nonzero.

However, it is possible for A to be less than B if Pow2 is a power of
two greater than 1.

Take for example:
i32 %A = 0
i32 %B = 31
i32 Pow2 = 2147483648

((Pow2 << 0) >>u 31) is non-zero but A is less than B.

This fixes PR21274.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219713 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 20:28:40 +00:00
Marcello Maggioni
db9fed93fa Switch to select optimization for two-case switches
This is the same optimization of r219233 with modifications to support PHIs with multiple incoming edges from the same block
and a test to check that this condition is handled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219656 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 01:58:26 +00:00
Sanjay Patel
e0a0018345 fix formatting; NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219645 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 00:33:23 +00:00
Chandler Carruth
ab1f4ef9a2 Add some optional passes around the vectorizer to both better prepare
the IR going into it and to clean up the IR produced by the vectorizers.

Note that these are *off by default* right now while folks collect data
on whether the performance tradeoff is reasonable.

In a build of the 'opt' binary, I see about 2% compile time regression
due to this change on average. This is in my mind essentially the worst
expected case: very little of the opt binary is going to *benefit* from
these extra passes.

I've seen several benchmarks improve in performance my small amounts due
to running these passes, and there are certain (rare) cases where these
passes make a huge difference by either enabling the vectorizer at all
or by hoisting runtime checks out of the outer loop. My primary
motivation is to prevent people from seeing runtime check overhead in
benchmarks where the existing passes and optimizers would be able to
eliminate that.

I've chosen the sequence of passes based on the kinds of things that
seem likely to be relevant for the code at each stage: rotaing loops for
the vectorizer, finding correlated values, loop invariants, and
unswitching opportunities from any runtime checks, and cleaning up
commonalities exposed by the SLP vectorizer.

I'll be pinging existing threads where some of these issues have come up
and will start new threads to get folks to benchmark and collect data on
whether this is the right tradeoff or we should do something else.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219644 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 00:31:29 +00:00
David Majnemer
af6be11a60 InstCombine: Fix miscompile in X % -Y -> X % Y transform
We assumed that negation operations of the form (0 - %Z) resulted in a
negative number.  This isn't true if %Z was originally negative.
Substituting the negative number into the remainder operation may result
in undefined behavior because the dividend might be INT_MIN.

This fixes PR21256.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219639 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-13 22:37:51 +00:00
David Majnemer
dfe81adbce InstCombine: Don't miscompile (x lshr C1) udiv C2
We have a transform that changes:
  (x lshr C1) udiv C2
into:
  x udiv (C2 << C1)

However, it is unsafe to do so if C2 << C1 discards any of C2's bits.

This fixes PR21255.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219634 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-13 21:48:30 +00:00
Joerg Sonnenberger
c6133c17e0 Revert r219223, it creates invalid PHI nodes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219587 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-12 17:16:04 +00:00
Benjamin Kramer
2b7b804fcc InstCombine: Turn (x != 0 & x <u C) into the canonical range check form (x-1 <u C-1)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219585 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-12 14:02:34 +00:00
David Majnemer
05f7e38c0b InstCombine: Simplify commonIDivTransforms
A helper routine, MultiplyOverflows, was a less efficient
reimplementation of APInt's smul_ov and umul_ov.  While we are here,
clean up the code so it's more uniform.

No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219583 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-12 08:34:24 +00:00
David Majnemer
171825a8ce InstCombine: Don't fold (X <<s log(INT_MIN)) /s INT_MIN to X
Consider the case where X is 2.  (2 <<s 31)/s-2147483648 is zero but we
would fold to X.  Note that this is valid when we are in the unsigned
domain because we require NUW: 2 <<u 31 results in poison.

This fixes PR21245.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219568 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-11 10:20:04 +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
2af441e26e InstCombine: mul to shl shouldn't preserve nsw
consider:
mul i32 nsw %x, -2147483648

this instruction will not result in poison if %x is 1

however, if we transform this into:
shl i32 nsw %x, 31

then we will be generating poison because we just shifted into the sign
bit.

This fixes PR21242.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219566 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-11 10:19:52 +00:00
Chandler Carruth
0b0126955a [SCEV] Fix one more caller blindly passing the latch to SCEV's
getSmallConstantTripCount even when it isn't the exiting block.

I missed this in my first audit, very sorry. This was found in LNT and
elsewhere. I don't have a test case, but it was completely obvious from
inspection that this was the problem. I'll see if I can reduce a test
case, but I'm not really hopeful, and the value seems quite low.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219562 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-11 05:28:30 +00:00
Chandler Carruth
c13c09106e [SCEV] Add some asserts to the recently improved trip count computation
routines and fix all of the bugs they expose.

I hit a test case that crashed even without these asserts due to passing
a non-exiting latch to the ExitingBlock parameter of the trip count
computation machinery. However, when I add the nice asserts, it turns
out we have plenty of coverage of these bugs, they just didn't manifest
in crashers.

The core problem seems to stem from an assumption that the latch *is*
the exiting block. While this is often true, and somewhat the "normal"
way to think about loops, it isn't necessarily true. The correct way to
call the trip count routines in a *generic* fashion (that is, without
a particular exit in mind) is to just use the loop's single exiting
block if it has one. The trip count can't be computed generically unless
it does. This works great for the loop vectorizer. The loop unroller
actually *wants* to select the latch when it has to chose between
multiple exits because for unrolling it is the latch trips that matter.
But if this is the desire, it needs to explicitly guard for non-exiting
latches and check for the generic trip count in that case.

I've added the asserts, and added convenience APIs for querying the trip
count generically that check for a single exit block. I've kept the APIs
consistent between computing trip count and trip multiples.

Thansk to Mark for the help debugging and tracking down the *right* fix
here!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219550 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-11 00:12:11 +00:00
Arnold Schwaighofer
dd8c386432 SimplifyCFG: Don't convert phis into selects if we could remove undef behavior
instead

We used to transform this:

  define void @test6(i1 %cond, i8* %ptr) {
  entry:
    br i1 %cond, label %bb1, label %bb2

  bb1:
    br label %bb2

  bb2:
    %ptr.2 = phi i8* [ %ptr, %entry ], [ null, %bb1 ]
    store i8 2, i8* %ptr.2, align 8
    ret void
  }

into this:

  define void @test6(i1 %cond, i8* %ptr) {
    %ptr.2 = select i1 %cond, i8* null, i8* %ptr
    store i8 2, i8* %ptr.2, align 8
    ret void
  }

because the simplifycfg transformation into selects would happen to happen
before the simplifycfg transformation that removes unreachable control flow
(We have 'unreachable control flow' due to the store to null which is undefined
behavior).

The existing transformation that removes unreachable control flow in simplifycfg
is:

  /// If BB has an incoming value that will always trigger undefined behavior
  /// (eg. null pointer dereference), remove the branch leading here.
  static bool removeUndefIntroducingPredecessor(BasicBlock *BB)

Now we generate:

  define void @test6(i1 %cond, i8* %ptr) {
    store i8 2, i8* %ptr.2, align 8
    ret void
  }

I did not see any impact on the test-suite + externals.

rdar://18596215

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219462 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-10 01:27:02 +00:00
Chad Rosier
c2bf8fbdf4 [Reassociate] Don't canonicalize X - undef to X + (-undef).
Phabricator Revision: http://reviews.llvm.org/D5674
PR21205

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219434 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 20:06:29 +00:00
Andrea Di Biagio
c53401ee91 [InstCombine] Fix wrong folding of constant comparisons involving ashr and negative values.
This patch fixes a bug in method InstCombiner::FoldCmpCstShrCst where we
wrongly computed the distance between the highest bits set of two negative
values.

This fixes PR21222.

Differential Revision: http://reviews.llvm.org/D5700


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219406 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 12:41:49 +00:00
Bob Wilson
8e673570b9 Use triple's isiOS() and isOSDarwin() methods.
These methods are already used in lots of places. This makes things more
consistent. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219386 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 05:43:30 +00:00
David Majnemer
b5b306e6a9 Inliner: Non-local functions in COMDATs shouldn't be dropped
A function with discardable linkage cannot be discarded if its a member
of a COMDAT group without considering all the other COMDAT members as
well.  This sort of thing is already handled by GlobalOpt/GlobalDCE.

This fixes PR21206.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219335 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 19:32:32 +00:00
Justin Bogner
41c4eb79d8 Revert "[InstCombine] re-commit r218721 with fix for pr21199"
This seems to cause a miscompile when building clang, which causes a
bootstrapped clang to fail or crash in several of its tests.

See:
  http://lab.llvm.org:8013/builders/clang-x86_64-darwin11-RA/builds/1184
  http://bb.pgr.jp/builders/clang-3stage-x86_64-linux/builds/7813

This reverts commit r219282.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219317 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 16:30:22 +00:00
Suyog Sarda
13ffdf88dc Format spacing and remove extra lines to comply with standards. NFC.
Differential Revision: http://reviews.llvm.org/D5649
 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219286 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 08:37:49 +00:00
David Majnemer
b07b0970b1 GlobalOpt: Don't drop unused memberes of a Comdat
A linkonce_odr member of a COMDAT shouldn't be dropped if we need to
keep the entire COMDAT group.

This fixes PR21191.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219283 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 07:23:31 +00:00
Gerolf Hoflehner
f8b5847bc4 [InstCombine] re-commit r218721 with fix for pr21199
The icmp-select-icmp optimization targets select-icmp.eq
only. This is now ensured by testing the branch predicate
explictly. This commit also includes the test case for pr21199.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219282 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 06:42:19 +00:00
Hans Wennborg
8315bd8ab0 Revert r219175 - [InstCombine] re-commit r218721 icmp-select-icmp optimization
This seems to have caused PR21199.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219264 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-08 01:05:57 +00:00
David Blaikie
5f3c0bafeb DebugInfo+DFSan: Ensure that debug info references to llvm::Functions remain pointing to the underlying function when wrappers are created
This is somewhat the inverse of how similar bugs in DAE and ArgPromo
manifested and were addressed. In those passes, individual call sites
were visited explicitly, and then the old function was deleted. This
left the debug info with a null llvm::Function* that needed to be
updated to point to the new function.

In the case of DFSan, it RAUWs the old function with the wrapper, which
includes debug info. So now the debug info refers to the wrapper, which
doesn't actually have any instructions with debug info in it, so it is
ignored entirely - resulting in a DW_TAG_subprogram with no high/low pc,
etc. Instead, fix up the debug info to refer to the original function
after the RAUW messed it up.

Reviewed/discussed with Peter Collingbourne on the llvm-dev mailing
list.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219249 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 22:59:46 +00:00
Duncan P. N. Exon Smith
de7465af34 LoopUnroll: Create sub-loops in LoopInfo
`LoopUnrollPass` says that it preserves `LoopInfo` -- make it so.  In
particular, tell `LoopInfo` about copies of inner loops when unrolling
the outer loop.

Conservatively, also tell `ScalarEvolution` to forget about the original
versions of these loops, since their inputs may have changed.

Fixes PR20987.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219241 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 21:19:00 +00:00
Duncan P. N. Exon Smith
9b303dcf12 LoopUnroll: Only check for ScalarEvolution analysis once, NFC
A follow-up commit will add use to a tight loop.  We might as well just
find it once anyway.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219239 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 21:12:44 +00:00
Marcello Maggioni
5c98f14b78 Two case switch to select optimization
This optimization tries to convert switch instructions that are used to select a value with only 2 unique cases + default block
to a select or a couple of selects (depending if the default block is reachable or not).

The typical case this optimization wants to be able to optimize is this one:

Example:
switch (a) {
  case 10:                %0 = icmp eq i32 %a, 10
    return 10;            %1 = select i1 %0, i32 10, i32 4
  case 20:        ---->   %2 = icmp eq i32 %a, 20
    return 2;             %3 = select i1 %2, i32 2, i32 %1
  default:
    return 4;
}

It also sets the base for further optimizations that are planned and being reviewed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219223 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 18:16:44 +00:00
David Blaikie
92f9736baf DebugInfo+DeadArgElimination: Ensure llvm::Function*s from debug info are updated even when DAE removes both varargs and non-varargs arguments on the same function.
After some stellar (& inspired) help from Reid Kleckner providing a test
case for some rather unstable undefined behavior showing up as
assertions produced by r214761, I was able to fix this issue in DAE
involving the application of both varargs removal, followed by normal
argument removal.

Indeed I introduced this same bug into ArgumentPromotion (r212128) by
copying the code from DAE, and when I fixed the bug in ArgPromo
(r213805) and commented in that patch that I didn't need to address the
same issue in DAE because it was a single pass. Turns out it's two pass,
one for the varargs and one for the normal arguments, so the same fix is
needed (at least during varargs removal). So here it is.

(the observable/net effect of this bug, even when it didn't result in
assertion failure, is that debug info would describe the DAE'd function
in the abstract, but wouldn't provide high/low_pc, variable locations,
line table, etc (it would appear as though the function had been
entirely optimized away), see the original PR14016 for details of the
general problem)

I'm not recommitting the assertion just yet, as there's been another
regression of it since I last tried. It might just be a few test cases
weren't adequately updated after Adrian or Duncan's recent schema
changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219210 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 15:10:23 +00:00
Suyog Sarda
7839762a3f Reformat if statement to comply with LLVM standards. NFC.
Differential Revision: http://reviews.llvm.org/D5644



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219203 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 12:04:07 +00:00
Suyog Sarda
1e4680c4b8 Reformat to comply with LLVM coding standards using clang-format.
NFC.

Differential Revision: http://reviews.llvm.org/D5645



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219202 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 11:56:06 +00:00
Tilmann Scheller
0ef79aa701 [InstCombine] Reformat if statements to comply with LLVM Coding Standards.
Patch by Sonam Kumari!

Differential Revision: http://reviews.llvm.org/D5643

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219198 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 10:19:34 +00:00
David Majnemer
2869d4800c GlobalDCE: Don't drop any COMDAT members
If we require a single member of a comdat, require all of the other
members as well.

This fixes PR20981.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219191 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-07 07:07:19 +00:00