Summary:
move the code from BreakCriticalEdges::runOnFunction()
into a separate utility function llvm::SplitAllCriticalEdges()
so that it can be used independently.
No functionality change intended.
Test Plan: check-llvm
Reviewers: nlewycky
Reviewed By: nlewycky
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D6313
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222288 91177308-0d34-0410-b5e6-96231b3b80d8
When converting a switch to a lookup table we might have to generate a bitmaks
to encode and check for holes in the original switch statement.
The type of this mask depends on the number of switch statements, which can
result in illegal types for pretty much all architectures.
To avoid unnecessary type legalization and help FastISel this commit increases
the size of the bitmask to next power-of-2 value when necessary.
This fixes rdar://problem/18984639.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222168 91177308-0d34-0410-b5e6-96231b3b80d8
This is a simple optimization for switch table lookup:
It computes the output value directly with an (optional) mul and add if there is a linear mapping between index and output.
Example:
int f1(int x) {
switch (x) {
case 0: return 10;
case 1: return 11;
case 2: return 12;
case 3: return 13;
}
return 0;
}
generates:
define i32 @f1(i32 %x) #0 {
entry:
%0 = icmp ult i32 %x, 4
br i1 %0, label %switch.lookup, label %return
switch.lookup:
%switch.offset = add i32 %x, 10
ret i32 %switch.offset
return:
ret i32 0
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222121 91177308-0d34-0410-b5e6-96231b3b80d8
Windows defines NULL to 0, which when used as an argument to a variadic
function, is not a null pointer constant. As a result, Clang's
-Wsentinel fires on this code. Using '0' would be wrong on most 64-bit
platforms, but both MSVC and Clang make it work on Windows. Sidestep the
issue with nullptr.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221940 91177308-0d34-0410-b5e6-96231b3b80d8
One of them (__memcpy_chk) was already there, the others were checked
by comparing function names.
Note that the fortified libfuncs are now part of TLI, but are always
available, because they aren't generated, only optimized into the
non-checking versions.
Differential Revision: http://reviews.llvm.org/D6179
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221817 91177308-0d34-0410-b5e6-96231b3b80d8
Instead, we're going to separate metadata from the Value hierarchy. See
PR21532.
This reverts commit r221375.
This reverts commit r221373.
This reverts commit r221359.
This reverts commit r221167.
This reverts commit r221027.
This reverts commit r221024.
This reverts commit r221023.
This reverts commit r220995.
This reverts commit r220994.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221711 91177308-0d34-0410-b5e6-96231b3b80d8
Switch statements may have more than one incoming edge into the same BB if they
all have the same value. When the switch statement is converted these incoming
edges are now coming from multiple BBs. Updating all incoming values to be from
a single BB is incorrect and would generate invalid LLVM IR.
The fix is to only update the first occurrence of an incoming value. Switch
lowering will perform subsequent calls to this helper function for each incoming
edge with a new basic block - updating all edges in the process.
This fixes rdar://problem/18916275.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221627 91177308-0d34-0410-b5e6-96231b3b80d8
We already use the llvm namespace. Remove the unnecessary prefix. Use the
StringRef::equals method to compare with C strings rather than instantiating
std::strings.
Addresses late review comments from David Majnemer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221564 91177308-0d34-0410-b5e6-96231b3b80d8
Visual Studio 2012 apparently does not support using alias declarations. Use
the more traditional typedef approach. This should let the Windows buildbots
pass. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221554 91177308-0d34-0410-b5e6-96231b3b80d8
This introduces the symbol rewriter. This is an IR->IR transformation that is
implemented as a CodeGenPrepare pass. This allows for the transparent
adjustment of the symbols during compilation.
It provides a clean, simple, elegant solution for symbol inter-positioning. This
technique is often used, such as in the various sanitizers and performance
analysis.
The control of this is via a custom YAML syntax map file that indicates source
to destination mapping, so as to avoid having the compiler to know the exact
details of the source to destination transformations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221548 91177308-0d34-0410-b5e6-96231b3b80d8
change LoopSimplifyPass to be !isCFGOnly. The motivation for the earlier patch
(r221223) was that LoopSimplify is not preserved by instcombine though
setPreservesCFG indicates that it is. This change fixes the issue
by making setPreservesCFG no longer imply LoopSimplifyPass, and is therefore less
invasive.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221311 91177308-0d34-0410-b5e6-96231b3b80d8
Change `Instruction::getAllMetadataOtherThanDebugLoc()` from a vector of
`MDNode` to one of `Value`. Part of PR21433.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221167 91177308-0d34-0410-b5e6-96231b3b80d8
Change `Instruction::getAllMetadata()` to modify a vector of `Value`
instead of `MDNode` and update call sites. This is part of PR21433.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221027 91177308-0d34-0410-b5e6-96231b3b80d8
Change `Instruction::getMetadata()` to return `Value` as part of
PR21433.
Update most callers to use `Instruction::getMDNode()`, which wraps the
result in a `cast_or_null<MDNode>`.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221024 91177308-0d34-0410-b5e6-96231b3b80d8
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
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
When we hoist two loads above an if, we can preserve the nonnull metadata. We could also do the same for sinking them, but we appear to not handle metadata at all in that case.
Thanks to Hal for the review.
Differential Revision: http://reviews.llvm.org/D5910
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220392 91177308-0d34-0410-b5e6-96231b3b80d8
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
combineMetadata is used when merging two instructions into one. This change teaches it how to merge 'nonnull' - i.e. only preserve it on the new instruction if it's set on both sources. This isn't actually used yet since I haven't adjusted any of the call sites to pass in nonnull as a 'known metadata'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220325 91177308-0d34-0410-b5e6-96231b3b80d8
When functions are inlined, instructions without debug information are
attributed to the call site's DebugLoc. After inlining, inlined static
allocas are moved to the caller's entry block, adjacent to the caller's
original static alloca instructions. By retaining the call site's
DebugLoc, these instructions could cause instructions that were
subsequently inserted at the entry block to pick up the same DebugLoc.
Patch by Wolfgang Pieb!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220255 91177308-0d34-0410-b5e6-96231b3b80d8
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
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
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
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
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
`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
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
`DIExpression`'s elements are 64-bit integers that are stored as
`ConstantInt`. The accessors already encapsulate the storage. This
commit updates the `DIBuilder` API to also encapsulate that.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218797 91177308-0d34-0410-b5e6-96231b3b80d8
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.
Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.
By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.
The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)
This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.
What this patch doesn't do:
This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.
http://reviews.llvm.org/D4919
rdar://problem/17994491
Thanks to dblaikie and dexonsmith for reviewing this patch!
Note: I accidentally committed a bogus older version of this patch previously.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218787 91177308-0d34-0410-b5e6-96231b3b80d8
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.
Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.
By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.
The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)
This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.
What this patch doesn't do:
This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.
http://reviews.llvm.org/D4919
rdar://problem/17994491
Thanks to dblaikie and dexonsmith for reviewing this patch!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218778 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch adds a threshold that controls the number of bonus instructions
allowed for folding branches with common destination. The original code allows
at most one bonus instruction. With this patch, users can customize the
threshold to allow multiple bonus instructions. The default threshold is still
1, so that the code behaves the same as before when users do not specify this
threshold.
The motivation of this change is that tuning this threshold significantly (up
to 25%) improves the performance of some CUDA programs in our internal code
base. In general, branch instructions are very expensive for GPU programs.
Therefore, it is sometimes worth trading more arithmetic computation for a more
straightened control flow. Here's a reduced example:
__global__ void foo(int a, int b, int c, int d, int e, int n,
const int *input, int *output) {
int sum = 0;
for (int i = 0; i < n; ++i)
sum += (((i ^ a) > b) && (((i | c ) ^ d) > e)) ? 0 : input[i];
*output = sum;
}
The select statement in the loop body translates to two branch instructions "if
((i ^ a) > b)" and "if (((i | c) ^ d) > e)" which share a common destination.
With the default threshold, SimplifyCFG is unable to fold them, because
computing the condition of the second branch "(i | c) ^ d > e" requires two
bonus instructions. With the threshold increased, SimplifyCFG can fold the two
branches so that the loop body contains only one branch, making the code
conceptually look like:
sum += (((i ^ a) > b) & (((i | c ) ^ d) > e)) ? 0 : input[i];
Increasing the threshold significantly improves the performance of this
particular example. In the configuration where both conditions are guaranteed
to be true, increasing the threshold from 1 to 2 improves the performance by
18.24%. Even in the configuration where the first condition is false and the
second condition is true, which favors shortcuts, increasing the threshold from
1 to 2 still improves the performance by 4.35%.
We are still looking for a good threshold and maybe a better cost model than
just counting the number of bonus instructions. However, according to the above
numbers, we think it is at least worth adding a threshold to enable more
experiments and tuning. Let me know what you think. Thanks!
Test Plan: Added one test case to check the threshold is in effect
Reviewers: nadav, eliben, meheff, resistor, hfinkel
Reviewed By: hfinkel
Subscribers: hfinkel, llvm-commits
Differential Revision: http://reviews.llvm.org/D5529
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218711 91177308-0d34-0410-b5e6-96231b3b80d8
Runtime unrolling will create a prologue to execute the extra
iterations which is can't divided by the unroll factor. It
generates an if-then-else sequence to jump into a factor -1
times unrolled loop body, like
extraiters = tripcount % loopfactor
if (extraiters == 0) jump Loop:
if (extraiters == loopfactor) jump L1
if (extraiters == loopfactor-1) jump L2
...
L1: LoopBody;
L2: LoopBody;
...
if tripcount < loopfactor jump End
Loop:
...
End:
It means if the unroll factor is 4, the loop body will be 7
times unrolled, 3 are in loop prologue, and 4 are in the loop.
This commit is to use a loop to execute the extra iterations
in prologue, like
extraiters = tripcount % loopfactor
if (extraiters == 0) jump Loop:
else jump Prol
Prol: LoopBody;
extraiters -= 1 // Omitted if unroll factor is 2.
if (extraiters != 0) jump Prol: // Omitted if unroll factor is 2.
if (tripcount < loopfactor) jump End
Loop:
...
End:
Then when unroll factor is 4, the loop body will be copied by
only 5 times, 1 in the prologue loop, 4 in the original loop.
And if the unroll factor is 2, new loop won't be created, just
as the original solution.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218604 91177308-0d34-0410-b5e6-96231b3b80d8
Rather than slurping in and splatting out the whole ctor list, preserve
the existing array entries without trying to understand them. Only
remove the entries that we know we can optimize away. This way we don't
need to wire through priority and comdats or anything else we might add.
Fixes a linker issue where the .init_array or .ctors entry would point
to discarded initialization code if the comdat group from the TU with
the faulty global_ctors entry was dropped.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218337 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: UsedByBranch is always true according to how BonusInst is defined.
Test Plan:
Passes check-all, and also verified
if (BonusInst && !UsedByBranch) {
...
}
is never entered during check-all.
Reviewers: resistor, nadav, jingyue
Reviewed By: jingyue
Subscribers: llvm-commits, eliben, meheff
Differential Revision: http://reviews.llvm.org/D5324
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217824 91177308-0d34-0410-b5e6-96231b3b80d8
