llvm-project.git/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp, branch users/nico/python-2

[AMDGPU][SDAG] Handle ISD::PTRADD in SelectionDAGAddressAnalysis (#142778)

2025-06-26T07:47:46+00:00

This is used in a bunch of memory-related transforms.

For SWDEV-516125.

[CodeGen] Update for scalable MemoryType in MMO (#70452)

2024-03-23T12:56:25+00:00

Remove getSizeOrUnknown call when MachineMemOperand is created.  For Scalable
TypeSize, the MemoryType created becomes a scalable_vector.

2 MMOs that have scalable memory access can then use the updated BasicAA that
understands scalable LocationSize.

Original Patch by Harvin Iriawan
Co-authored-by: David Green

[SelectionDAG] Change computeAliasing signature from optional to LocationSize. (#83017)

2024-02-28T09:43:05+00:00

This is another smaller step of #70452, changing the signature of
computeAliasing() from optional to LocationSize, and follow-up
changes in DAGCombiner::mayAlias(). There are some test change due to
the previous AA->isNoAlias call incorrectly using an unknown size
(~UINT64_T(0)). This should then be improved again in #70452 when the
types are known to be scalable.

[DAG] BaseIndexOffset::equalBaseIndex - early out on failed matches. NFCI.

2024-01-04T10:50:43+00:00

If we successfully cast only the first base node as GlobalAddressSDNode / ConstantPoolSDNode / FrameIndexSDNode then we can early out as we know that base won't cast as a later type.

Noticed while investigating profiles for potential compile time improvements.

[DAG] BaseIndexOffset::computeAliasing - early out on failed matches. NFCI.

2024-01-04T10:50:42+00:00

Don't wait to test that all base ptr matches have succeeded

[X86] Fix aliasing check between TargetFrameIndex and FrameIndex

2023-08-17T09:48:08+00:00

Compare slot indices instead of comparing pointer values.

Closes #63645

Differential Revision: https://reviews.llvm.org/D157513

[CodeGen] llvm::Optional => std::optional

2022-12-13T09:06:36+00:00

[llvm] Don't use Optional::hasValue (NFC)

2022-06-20T17:38:12+00:00

[SelectionDAG] Replace error prone index check in BaseIndexOffset::computeAliasing

2021-10-05T10:15:55+00:00

Deriving NoAlias based on having the same index in two BaseIndexOffset
expressions seemed weird (and as shown in the added unittest the
correctness of doing so depended on undocumented pre-conditions that
the user of BaseIndexOffset::computeAliasing would need to take care
of.

This patch removes the code that dereived NoAlias based on indices
being the same. As a compensation, to avoid regressions/diffs in
various lit test, we also add a new check. The new check derives
NoAlias in case the two base pointers are based on two different
GlobalValue:s (neither of them being a GlobalAlias).

Reviewed By: niravd

Differential Revision: https://reviews.llvm.org/D110256

[SelectionDAG] Assume that a GlobalAlias may alias other global values

2021-10-05T10:15:55+00:00

This fixes a bug detected in DAGCombiner when using global alias
variables. Here is an example:
  @foo = global i16 0, align 1
  @aliasFoo = alias i16, i16 * @foo
  define i16 @bar() {
    ...
    store i16 7, i16 * @foo, align 1
    store i16 8, i16 * @aliasFoo, align 1
    ...
  }

BaseIndexOffset::computeAliasing would incorrectly derive NoAlias
for the two accesses in the example above, resulting in DAGCombiner
miscompiles.

This patch fixes the problem by a defensive approach letting
BaseIndexOffset::computeAliasing return false, i.e. that the aliasing
couldn't be determined, when comparing two global values and at least
one is a GlobalAlias. In the future we might improve this with a
deeper analysis to look at the aliasee for the GlobalAlias etc. But
that is a bit more complicated considering that we could have
'local_unnamed_addr' and situations with several 'alias' variables.

Fixes PR51878.

Differential Revision: https://reviews.llvm.org/D110064