In preparation for porting this pass to the new PM (which has no
doInitialization()).
Differential Revision: http://reviews.llvm.org/D22223
llvm-svn: 275074
Summary:
For sample-based PGO, using BFI to calculate callsite count is sometime not accurate. This is because with sampling based approach, if a callsite resides in a hot loop deeply nested in a bunch of cold branches, the callsite's BFI frequency would be inaccurately calculated due to lack of samples in the cold branch.
E.g.
if (A1 && A2 && A3 && ..... && A10) {
for (i=0; i < 100000000; i++) {
callsite();
}
}
Assume that A1 to A100 are all 100% taken, and callsite has 1000 samples and thus is considerred hot. Because the loop's trip count is huge, it's normal that all branches outside the loop has no sample at all. As a result, we can only use static branch probability to derive the the frequency of the loop header. Assuming that static heuristic thinks each branch is 50% taken, then the count calculated from BFI will be 1/(2^10) of the actual value.
In order to get more accurate callsite count, we directly annotate the weight on the call instruction, and directly use it when checking callsite hotness.
Note that this mechanism can also be shared by instrumentation based callsite hotness analysis. The side benefit is that it breaks the dependency from Inliner to BFI as call count is embedded in the IR.
Reviewers: davidxl, eraman, dnovillo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D22118
llvm-svn: 275073
Summary: Handle the case when there is only one incoming/outgoing edge for a visited basic block: use the block weight to adjust edge weight even when the edge has been visited before. This can help reduce inaccuracies introduced by incorrect basic block profile, as shown in the updated unittest.
Reviewers: davidxl, dnovillo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D22180
llvm-svn: 275072
This subtle change to getModRefInfo(Instruction, ImmutableCallSite) is to
ensure that the semantics are equal to that of getModRefInfo(CS1, CS2) when
the Instruction is a call-site.
This is now more in line with getModRefInfo generally: it returns Mod when
I modifies a memory location that is accessed (read or written) by CS and
Ref when I reads a memory location that is written by CS.
From a grep of the code, the only uses of this particular getModRefInfo
overload are in MemorySSA and MemCpyOptimizer, and they only care about
where the result is MR_NoModRef or not. Therefore, this change should have
no visible effect.
Separated out from D17279 upon request.
llvm-svn: 275065
At present the only shuffle with a variable mask we recognise is PSHUFB, which influences if its worth the cost of mask creation/loading of a combined target shuffle with a variable mask. This change sets up the infrastructure to support other shuffles in the future but has no effect yet.
llvm-svn: 275059
Preserve assembly comments from input in output assembly and flags to
toggle property. This is on by default for inline assembly and off in
llvm-mc.
Parsed comments are emitted immediately before an EOL which generally
places them on the expected line.
Reviewers: rtrieu, dwmw2, rnk, majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D20020
llvm-svn: 275058
For functions which are known to return a specific argument, pointer-comparison
folding can look through the function calls as part of its analysis.
Differential Revision: http://reviews.llvm.org/D9387
llvm-svn: 275039
For functions which are known to return their argument,
isDereferenceableAndAlignedPointer can examine the argument value.
Differential Revision: http://reviews.llvm.org/D9384
llvm-svn: 275038
When building SCEVs, if a function is known to return its argument, then we can
build the SCEV using the corresponding argument value.
Differential Revision: http://reviews.llvm.org/D9381
llvm-svn: 275037
If a function is known to return one of its arguments, we can use that in order
to compute known bits of the return value.
Differential Revision: http://reviews.llvm.org/D9397
llvm-svn: 275036
Motivated by the work on the llvm.noalias intrinsic, teach BasicAA to look
through returned-argument functions when answering queries. This is essential
so that we don't loose all other AA information when supplementing with
llvm.noalias.
Differential Revision: http://reviews.llvm.org/D9383
llvm-svn: 275035
In order to make the optimizer smarter about using the 'returned' argument
attribute (generally, but motivated by my llvm.noalias intrinsic work), add a
utility function to Call/InvokeInst, and CallSite, to make it easy to get the
returned call argument (when one exists).
P.S. There is already an unfortunate amount of code duplication between
CallInst and InvokeInst, and this adds to it. We should probably clean that up
separately.
Differential Revision: http://reviews.llvm.org/D22204
llvm-svn: 275031
Calls to matchVectorShuffleAsInsertPS only need to ensure the inputs are 128-bit vectors. Only lowerVectorShuffleAsInsertPS needs to ensure that they are v4f32.
llvm-svn: 275028
A function can have one argument with the 'returned' attribute, indicating that
the associated argument is always the return value of the function. Add
FuncAttrs inference logic.
Differential Revision: http://reviews.llvm.org/D22202
llvm-svn: 275027
This adds a new SystemZ-specific intrinsic, llvm.s390.tdc.f(32|64|128),
which maps straight to the test data class instructions. A new IR pass
is added to recognize instructions that can be converted to TDC and
perform the necessary replacements.
Differential Revision: http://reviews.llvm.org/D21949
llvm-svn: 275016
Some abstractions in LLVM "know" that they are reading in-bounds,
FixedStreamArray, and provide a simple result. This breaks down if the
stream map is bogus.
llvm-svn: 275010
In the solver, isUndefined() does really mean "we don't know the
value yet" rather than "this is an UndefinedValue". Discussed with
Eli Friedman.
Differential Revision: http://reviews.llvm.org/D22192
llvm-svn: 275004
This code was already commented out and it made some weird assumptions,
e.g. using isUndefined() as "this value is UndefValue" instead of
"we haven't computed this value is yet". Thanks to Eli Friedman for
pointing out where I was wrong (and where this code was wrong).
llvm-svn: 274995
ConstantInt::getSExtValue may fail on >64-bit integers. Add checks to call
getSExtValue only on narrow integers.
As a minor aside, simplify slsr-gep.ll to remove unnecessary load instructions.
llvm-svn: 274982
