Summary:
Instances of the AssumptionCache are per function, so we can't re-use
the same AssumptionCache instance when recursing in the CallAnalyzer to
analyze a different function. Instead we have to pass the
AssumptionCacheTracker to the CallAnalyzer so it can get the right
AssumptionCache on demand.
Reviewers: hfinkel
Subscribers: llvm-commits, hans
Differential Revision: http://reviews.llvm.org/D7533
llvm-svn: 228957
We can't solve the full subgraph isomorphism problem. But we can
allow obvious cases, where for example two instructions of different
types are out of order. Due to them having different types/opcodes,
there is no ambiguity.
llvm-svn: 228931
Now that SimplifyCFG uses TTI for the cost heuristic, we can teach BasicTTIImpl
how to query TLI in order to get a more accurate cost for truncates and
zero-extends.
Before this patch, the basic cost heuristic in TargetTransformInfoImplCRTPBase
would have conservatively returned a 'default' TCC_Basic for all zero-extends,
and TCC_Free for truncates on native types.
This patch improves the heuristic so that we query TLI (if available) to get
more accurate answers. If TLI is available, then methods 'isZExtFree' and
'isTruncateFree' can be used to check if a zext/trunc is free for the target.
Added more test cases to SimplifyCFG/X86/speculate-cttz-ctlz.ll.
With this change, SimplifyCFG is now able to speculate a 'cheap' cttz/ctlz
immediately followed by a free zext/trunc.
Differential Revision: http://reviews.llvm.org/D7585
llvm-svn: 228923
Apparently some code finally started to tickle this after my
canonicalization changes to instcombine.
The bug stems from trying to form a vector type out of scalars that
aren't compatible at all. In this example, from x86_mmx values. The code
in the vectorizer that checks for reasonable types whas checking for
aggregates or vectors, but there are lots of other types that should
just never reach the vectorizer.
Debugging this was made more confusing by the lie in an assert in
VectorType::get() -- it isn't that the types are *primitive*. The types
must be integer, pointer, or floating point types. No other types are
allowed.
I've improved the assert and added a helper to the vectorizer to handle
the element type validity checks. It now re-uses the VectorType static
function and then further excludes weird target-specific types that we
probably shouldn't be touching here (x86_fp80 and ppc_fp128). Neither of
these are really reachable anyways (neither 80-bit nor 128-bit things
will get vectorized) but it seems better to just eagerly exclude such
nonesense.
I've added a test case, but while it definitely covers two of the paths
through this code there may be more paths that would benefit from test
coverage. I'm not familiar enough with the SLP vectorizer to synthesize
test cases for all of these, but was able to update the code itself by
inspection.
llvm-svn: 228899
I mistakenly thought the liveness of each "RetVal(F, i)" depended only on F. It
actually depends on the index too, which means we need to be careful about how
the results are combined before return. In particular if a single Use returns
Live, that counts for the entire object, at the granularity we're considering.
llvm-svn: 228885
Summary:
When trying to canonicalize negative constants out of
multiplication expressions, we need to check that the
constant is not INT_MIN which cannot be negated.
Reviewers: mcrosier
Reviewed By: mcrosier
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7286
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 228872
This patch is a follow-up of r228826 (see code-review: D7506).
Now that SimplifyCFG uses TargetTransformInfo for cost analysis, we
have to fix the cost heuristic for intrinsic calls to cttz/ctlz.
This patch defines method 'getIntrinsicCost' in BasicTTIImpl: now, BasicTTIImpl
queries TLI to check if a call to cttz/ctlz is cheap for the target.
Added test cases in Transforms/SimplifyCFG/X86 to verify that on x86,
SimplifyCFG only speculates a call to cttz/ctlz if it is cheap.
Differential Revision: http://reviews.llvm.org/D7554
llvm-svn: 228829
analysis.
We're already using TTI in SimplifyCFG, so remove the hard-baked "cheapness"
heuristic and use TTI directly. Generally NFC intended, but we're using a slightly
different heuristic now so there is a slight test churn.
Test changes:
* combine-comparisons-by-cse.ll: Removed unneeded branch check.
* 2014-08-04-muls-it.ll: Test now doesn't branch but emits muleq.
* coalesce-subregs.ll: Superfluous block check.
* 2008-01-02-hoist-fp-add.ll: fadd is safe to speculate. Change to udiv.
* PhiBlockMerge.ll: Superfluous CFG checking code. Main checks still present.
* select-gep.ll: A variable GEP is not expensive, just TCC_Basic, according to the TTI.
llvm-svn: 228826
A DAGRootSet models an induction variable being used in a rerollable
loop. For example:
x[i*3+0] = y1
x[i*3+1] = y2
x[i*3+2] = y3
Base instruction -> i*3
+---+----+
/ | \
ST[y1] +1 +2 <-- Roots
| |
ST[y2] ST[y3]
There may be multiple DAGRootSets, for example:
x[i*2+0] = ... (1)
x[i*2+1] = ... (1)
x[i*2+4] = ... (2)
x[i*2+5] = ... (2)
x[(i+1234)*2+5678] = ... (3)
x[(i+1234)*2+5679] = ... (3)
This concept is similar to the "Scale" member used previously, but allows
multiple independent sets of roots based off the same induction variable.
llvm-svn: 228821
If the landingpad of the invoke is using a personality function that
catches asynch exceptions, then it can catch a trap.
Also add some landingpads to invalid LLVM IR test cases that lack them.
Over-the-shoulder reviewed by David Majnemer.
llvm-svn: 228782
Unless we meet an insertvalue on a path from some value to a return, that value
will be live if *any* of the return's components are live, so all of those
components must be added to the MaybeLiveUses.
Previously we were deleting arguments if sub-value 0 turned out to be dead.
llvm-svn: 228731
This commit isn't using the correct context, and is transfoming calls
that are operands to loads rather than calls that are operands to an
icmp feeding into an assume. I've replied on the original review thread
with a very reduced test case and some thoughts on how to rework this.
llvm-svn: 228677
These tests the two optimizations for backedge insertion currently implemented and the split backedge flag which is currently off by default.
llvm-svn: 228617
This is just adding really simple tests which should have been part of the original submission. When doing so, I discovered that I'd mistakenly removed required pieces when preparing the patch for upstream submission. I fixed two such bugs in this submission.
llvm-svn: 228610
Some parts of DeadArgElim were only considering the individual fields
of StructTypes separately, but others (where insertvalue &
extractvalue instructions occur) also looked into ArrayTypes.
This one is an actual bug; the mismatch can lead to an argument being
considered used by a return sub-value that isn't being tracked (and
hence is dead by default). It then gets incorrectly eliminated.
llvm-svn: 228559
Previously, a non-extractvalue use of an aggregate return value meant
the entire return was considered live (the algorithm gave up
entirely). This was correct, but conservative. It's better to actually
look at that Use, making the analysis results apply to all sub-values
under consideration.
E.g.
%val = call { i32, i32 } @whatever()
[...]
ret { i32, i32 } %val
The return is using the entire aggregate (sub-values 0 and 1). We can
still simplify @whatever if we can prove that this return is itself
unused.
Also unifies the logic slightly between aggregate and non-aggregate
cases..
llvm-svn: 228558
Make assume (load (call|invoke) != null) set nonNull return attribute
for the call and invoke. Also include tests.
Differential Revision: http://reviews.llvm.org/D7107
llvm-svn: 228556
Summary:
The alias.scope metadata represents sets of things an instruction might
alias with. When generically combining the metadata from two
instructions the result must be the union of the original sets, because
the new instruction might alias with anything any of the original
instructions aliased with.
Reviewers: hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7490
llvm-svn: 228525
Normalize
select(C0, select(C1, a, b), b) -> select((C0 & C1), a, b)
select(C0, a, select(C1, a, b)) -> select((C0 | C1), a, b)
This normal form may enable further combines on the And/Or and shortens
paths for the values. Many targets prefer the other but can go back
easily in CodeGen.
Differential Revision: http://reviews.llvm.org/D7399
llvm-svn: 228409
Summary: When evaluating floating point instructions in the inliner, ask the TTI whether it is an expensive operation. By default, it's not an expensive operation. This keeps the default behavior the same as before. The ARM TTI has been updated to return back TCC_Expensive for targets which don't have hardware floating point.
Reviewers: chandlerc, echristo
Reviewed By: echristo
Subscribers: t.p.northover, aemerson, llvm-commits
Differential Revision: http://reviews.llvm.org/D6936
llvm-svn: 228263
We were previously doing a post-order traversal and operating on the
list in reverse, however this would occasionaly cause backedges for
loops to be visited before some of the other blocks in the loop.
We know use a reverse post-order traversal, which avoids this issue.
The reverse post-order traversal is not completely ideal, so we need
to manually fixup the list to ensure that inner loop backedges are
visited before outer loop backedges.
llvm-svn: 228186
This reverts patches 223862, 224198, 224203, and 224754, which were all
related to the vector load/store combining and were reverted/reaplied
a few times due to the same alignment problems we're seeing now.
Further tests, mainly self-hosting Clang, will be needed to reapply this
patch in the future.
llvm-svn: 228129
Summary:
Straight-line strength reduction (SLSR) is implemented in GCC but not yet in
LLVM. It has proven to effectively simplify statements derived from an unrolled
loop, and can potentially benefit many other cases too. For example,
LLVM unrolls
#pragma unroll
foo (int i = 0; i < 3; ++i) {
sum += foo((b + i) * s);
}
into
sum += foo(b * s);
sum += foo((b + 1) * s);
sum += foo((b + 2) * s);
However, no optimizations yet reduce the internal redundancy of the three
expressions:
b * s
(b + 1) * s
(b + 2) * s
With SLSR, LLVM can optimize these three expressions into:
t1 = b * s
t2 = t1 + s
t3 = t2 + s
This commit is only an initial step towards implementing a series of such
optimizations. I will implement more (see TODO in the file commentary) in the
near future. This optimization is enabled for the NVPTX backend for now.
However, I am more than happy to push it to the standard optimization pipeline
after more thorough performance tests.
Test Plan: test/StraightLineStrengthReduce/slsr.ll
Reviewers: eliben, HaoLiu, meheff, hfinkel, jholewinski, atrick
Reviewed By: jholewinski, atrick
Subscribers: karthikthecool, jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D7310
llvm-svn: 228016
The commit r225977 uncovered this bug. The problem was that the vectorizer tried to
read the second operand of an already deleted instruction.
The bug didn't show up before r225977 because the freed memory still contained a non-null pointer.
With r225977 deletion of instructions is delayed and the read operand pointer is always null.
llvm-svn: 227800
This should be sufficient to replace the initial (minor) function pass
pipeline in Clang with the new pass manager. I'll probably add an (off
by default) flag to do that just to ensure we can get extra testing.
llvm-svn: 227726
I've added RUN lines both to the basic test for EarlyCSE and the
target-specific test, as this serves as a nice test that the TTI layer
in the new pass manager is in fact working well.
llvm-svn: 227725
Previously, only -1 and +1 step values are supported for induction variables. This patch extends LV to support
arbitrary constant steps.
Initial patch by Alexey Volkov. Some bug fixes are added in the following version.
Differential Revision: http://reviews.llvm.org/D6051 and http://reviews.llvm.org/D7193
llvm-svn: 227557
In http://reviews.llvm.org/D6911, we allowed GVN to propagate FP equalities
to allow some simple value range optimizations. But that introduced a bug
when comparing to -0.0 or 0.0: these compare equal even though they are not
bitwise identical.
This patch disallows propagating zero constants in equality comparisons.
Fixes: http://llvm.org/bugs/show_bug.cgi?id=22376
Differential Revision: http://reviews.llvm.org/D7257
llvm-svn: 227491
Patch by: Igor Laevsky <igor@azulsystems.com>
"Currently SplitBlockPredecessors generates incorrect code in case if basic block we are going to split has a landingpad. Also seems like it is fairly common case among it's users to conditionally call either SplitBlockPredecessors or SplitLandingPadPredecessors. Because of this I think it is reasonable to add this condition directly into SplitBlockPredecessors."
Differential Revision: http://reviews.llvm.org/D7157
llvm-svn: 227390
Reduce integer multiplication by a constant of the form k*2^c, where k is in {3,5,9} into a lea + shl. Previously it was only done for imulq on 64-bit platforms, but it makes sense for imull and 32-bit as well.
Differential Revision: http://reviews.llvm.org/D7196
llvm-svn: 227308
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
llvm-svn: 227298
