Recommiting after adding check to avoid miscomputing alias information
on addresses of the same base but different subindices.
Memory accesses offset from frame indices may alias, e.g., we
may merge write from function arguments passed on the stack when they
are contiguous. As a result, when checking aliasing, we consider the
underlying frame index's offset from the stack pointer.
Static allocs are realized as stack objects in SelectionDAG, but its
offset is not set until post-DAG causing DAGCombiner's alias check to
consider access to static allocas to frequently alias. Modify isAlias
to consider access between static allocas and access from other frame
objects to be considered aliasing.
Many test changes are included here. Most are fixes for tests which
indirectly relied on our aliasing ability and needed to be modified to
preserve their original intent.
The remaining tests have minor improvements due to relaxed
ordering. The exception is CodeGen/X86/2011-10-19-widen_vselect.ll
which has a minor degradation dispite though the pre-legalized DAG is
improved.
Reviewers: rnk, mkuper, jonpa, hfinkel, uweigand
Reviewed By: rnk
Subscribers: sdardis, nemanjai, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D33345
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308025 91177308-0d34-0410-b5e6-96231b3b80d8
Memory accesses offset from frame indices may alias, e.g., we
may merge write from function arguments passed on the stack when they
are contiguous. As a result, when checking aliasing, we consider the
underlying frame index's offset from the stack pointer.
Static allocs are realized as stack objects in SelectionDAG, but its
offset is not set until post-DAG causing DAGCombiner's alias check to
consider access to static allocas to frequently alias. Modify isAlias
to consider access between static allocas and access from other frame
objects to be considered aliasing.
Many test changes are included here. Most are fixes for tests which
indirectly relied on our aliasing ability and needed to be modified to
preserve their original intent.
The remaining tests have minor improvements due to relaxed
ordering. The exception is CodeGen/X86/2011-10-19-widen_vselect.ll
which has a minor degradation dispite though the pre-legalized DAG is
improved.
Reviewers: rnk, mkuper, jonpa, hfinkel, uweigand
Reviewed By: rnk
Subscribers: sdardis, nemanjai, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D33345
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307546 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Add a combine for creating a truncate to replace a build_vector composed of extracts with
indices that form a stride-2^N series.
Example:
v8i32 V = ...
v4i32 build_vector((extract_elt V, 0), (extract_elt V, 2), (extract_elt V, 4), (extract_elt V, 6))
-->
v4i32 truncate (bitcast V to v4i64)
Related discussion in llvm-dev about canonicalizing shuffles to
truncates in LLVM IR:
http://lists.llvm.org/pipermail/llvm-dev/2017-January/108936.html.
Reviewers: spatel, RKSimon, efriedma, igorb, craig.topper, wolfgangp, delena
Reviewed By: delena
Subscribers: guyblank, delena, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D34077
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307036 91177308-0d34-0410-b5e6-96231b3b80d8
Relanding after restricting equalBaseIndex to not erroneuosly consider
a FrameIndices stemming from alloca from being comparable as its
offset is set post-selectionDAG.
Pull FrameIndex comparision reasoning from DAGCombiner::isAlias to
general BaseIndexOffset.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306688 91177308-0d34-0410-b5e6-96231b3b80d8
That is pretty common for clang to produce code like
(shl %x, (and %amt, 31)). In this situation we can still perform
trunc (shl) into shl (trunc) conversion given the known value
range of shift amount.
Differential Revision: https://reviews.llvm.org/D34723
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306499 91177308-0d34-0410-b5e6-96231b3b80d8
When SelectionDAG merges consecutive stores and loads in MergeConsecutiveStores, it does not set dereferenceable flag for a created load instruction. This results in an assertion failure if SelectionDAG commonizes this load instruction with other load instructions, as well as it may miss optimization opportunities.
This patch sat dereferenceable flag for the newly created load instruction if all the load instructions to be merged are dereferenceable.
Differential Revision: https://reviews.llvm.org/D34679
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306404 91177308-0d34-0410-b5e6-96231b3b80d8
Move GlobalAddress Offset decomposition from initial match into
comparision check and removing the possibility of constructing a new
offseted global address when examining addresses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305917 91177308-0d34-0410-b5e6-96231b3b80d8
Add support for combining a build vector to a shuffle.
When the build vector is of extracted elements from 2 vectors (vec1, vec2) where vec2 is 2 times smaller than vec1.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305883 91177308-0d34-0410-b5e6-96231b3b80d8
As all store merges checks are based on the memory operation
performed, allow use of truncated stores and extended loads as valid
input candidates for merging.
Relanding after fixing selection between truncated and normal store.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305701 91177308-0d34-0410-b5e6-96231b3b80d8
In preparation for doing storemerge post-legalization, reorder
visitSTORE passes to move pre/post-index combining after store
merge. Reordered passes other than store merge are unaffected.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305473 91177308-0d34-0410-b5e6-96231b3b80d8
As all store merges checks are based on the memory operation
performed, allow use of truncated stores and extended loads as valid
input candidates for merging.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305468 91177308-0d34-0410-b5e6-96231b3b80d8
Avoid non-legal memory ops by checking correct size when merging
stores of loads into a extload-truncstore pair.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305466 91177308-0d34-0410-b5e6-96231b3b80d8
This step is just intended to reduce code duplication rather than change any functionality.
A follow-up would be to replace PPCTargetLowering::spliceIntoChain() usage with this new helper.
Differential Revision: https://reviews.llvm.org/D33649
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305192 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: UADDO has 2 result, and one must check the result no before doing any kind of combine. Without it, the transform is invalid.
Reviewers: joerg
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D34088
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305162 91177308-0d34-0410-b5e6-96231b3b80d8
When considering merging stores values are the results of loads only
consider stores whose values come from loads from the same base.
This fixes much of the longer compile times in PR33330.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304934 91177308-0d34-0410-b5e6-96231b3b80d8
Other calls to DAGCombiner::*PromoteOperand check the result, but here it could cause an assertion in getNode.
Falling back to any extend in this case instead of failing outright seems correct to me.
No test case because:
The failure was triggered by an out of tree backend. In order to trigger it, a backend would need to overload
TargetLowering::IsDesirableToPromoteOp to return true for a type for which ISD::SIGN_EXTEND_INREG is marked
illegal. In tree, only X86 overloads and sometimes returns true for MVT::i16 yet it marks
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i16 , Legal);.
Patch by Jacob Young!
Differential Revision: https://reviews.llvm.org/D33633
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304723 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is a problem uncovered by stage2 testing. ADDCARRY end up being generated on target that do not support it.
The patch that introduced the problem has other patches layed on top of it, so we want to fix the issue rather than revert it to avoid creating a lor of churn.
A regression test will be added shortly, but this is committed as this in order to get the build back to green promptly.
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33770
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304409 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is a continuation of the work started in D29872 . Passing the carry down as a value rather than as a glue allows for further optimizations. Introducing setcccarry makes the use of addc/subc unecessary and we can start the removal process.
This patch only introduce the optimization strictly required to get the same level of optimization as was available before nothing more.
Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33374
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304404 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: This pattern is no very useful per se, but it exposes optimization for toehr patterns that wouldn't kick in otherwize. It's very common and worth optimizing for.
Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32756
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304402 91177308-0d34-0410-b5e6-96231b3b80d8
