Fixes#149179
The issue is that `Builder.CreateGEP` does not return a GEP Instruction
or GEP ContantExpr when the pointer operand is a global variable and all
indices are constant zeroes.
This PR ensures that a GEP instruction is created if `Builder.CreateGEP`
did not return a GEP.
In tandem with #146800, this PR fixes#145370
This PR simplifies the logic for collapsing GEP chains and replacing
GEPs to multidimensional arrays with GEPs to flattened arrays. This
implementation avoids unnecessary recursion and more robustly computes
the index to the flattened array by using the GEPOperator's
collectOffset function, which has the side effect of allowing "i8 GEPs"
and other types of GEPs to be handled naturally in the flattening /
collapsing of GEP chains.
Furthermore, a handful of LLVM DirectX CodeGen tests have been edited to
fix incorrect GEP offsets, mismatched types (e.g., loading i32s from a
an array of floats), and typos.
fixes#142836
We added a function called `collectIndicesAndDimsFromGEP` which builds
the Indicies and Dims up for the recursive case and the base case.
really to solve #142836 we didn't need to add it to the recursive case.
The recursive cases exists for gep chains which are ussually two
indicies per gep ie ptr index and array index. adding
collectIndicesAndDimsFromGEP to the recursive cases means we can now do
some mixed mode indexing say we get a case where its not the ussual 2
indicies but instead 3 we can now treat those last two indicies as part
of the computation for the flat array index.
This change relands https://github.com/llvm/llvm-project/pull/142853
It fixes the circular reference issue we were seeing in GEPs
ex `%.flat = getelementptr inbounds [16 x i32], ptr %.flat, i32 0, i32
15`
partially fixes#142836
- Update DXILFlattenArrays.cpp GEPs to use two indicies since they are
array GEPs
- Update flatten test cases
- This change reduces dxv bitcast validation errors by 364 (Total now is
1070x)
- This change reduces dxv out of bounds validation errors by 124 (Total
is now 24)
- We are also able to successfully compile 4 more shaders
- Relevant piece is `DXILFlattenArrays.cpp`
- Loads and Store Instruction visits are just for finding
GetElementPtrConstantExpr and splitting them.
- Allocas needed to be replaced with flattened allocas.
- Global arrays were similar to allocas. Only interesting piece here is
around initializers.
- Most of the work went into building correct GEP chains. The approach
here was a recursive strategy via `recursivelyCollectGEPs`.
- All intermediary GEPs get marked for deletion and only the leaf GEPs
get updated with the new index.
fixes [89646](https://github.com/llvm/llvm-project/issues/89646)
