This PR fixes issue https://github.com/llvm/llvm-project/issues/87763
and preserves valid CFG in cases when previous scheme failed to generate
valid code for a switch statement. The PR hardens one existing test case
and adds one more test case as a validation of a new switch generation.
Tests are passing spirv-val now.
This PR also improves validation of forward calls.
This PR introduces a step after instruction selection where instructions
can be traversed from the perspective of their validity from the
specification point of view. The PR adds also a way to correct
load/store when there is a type mismatch contradicting the specification
-- an additional bitcast is inserted to keep types consistent.
Correspondent test cases are added and existing test cases are
corrected.
This PR helps to successfully validate with the `spirv-val` tool
(https://github.com/KhronosGroup/SPIRV-Tools) some output that
previously led to validation errors and crashes of back translation from
SPIRV to LLVM IR from the side of SPIRV Translator project
(https://github.com/KhronosGroup/SPIRV-LLVM-Translator).
The added step of bringing instructions to required by the specification
type correspondence can be (should be and will be) extended beyond
load/store instructions to ensure validity rules of other SPIRV
instructions related to type inference.
This PR is to prevent creation of jump tables from switch. The reason is
that SPIR-V doesn't know how to lower jump tables, and a sequence of
commands that IRTranslator generates for switch via jump tables breaks
SPIR-V Backend code generation with complains to G_BRJT. The next
example is the shortest code to break SPIR-V Backend code generation in
this way:
```
target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64"
target triple = "spir64-unknown-unknown"
define spir_func void @foo(i32 noundef %val) {
entry:
switch i32 %val, label %sw.epilog [
i32 0, label %sw.bb
i32 1, label %sw.bb2
i32 2, label %sw.bb3
i32 3, label %sw.bb4
]
sw.bb:
br label %sw.epilog
sw.bb2:
br label %sw.epilog
sw.bb3:
br label %sw.epilog
sw.bb4:
br label %sw.epilog
sw.epilog:
ret void
}
```
To resolve the issue we set a high lower limit for number of blocks in a
jump table via getMinimumJumpTableEntries() and prevent undesirable (or
rather unsupported at the moment) path of code generation.
The patch adds the regularization pass that prepare LLVM IR for
the IR translation. It also contains following changes:
- reduce indentation, make getNonParametrizedType, getSamplerType,
getPipeType, getImageType, getSampledImageType static in SPIRVBuiltins,
- rename mayBeOclOrSpirvBuiltin to getOclOrSpirvBuiltinDemangledName,
- move isOpenCLBuiltinType, isSPIRVBuiltinType, isSpecialType from
SPIRVGlobalRegistry.cpp to SPIRVUtils.cpp, renaming isSpecialType to
isSpecialOpaqueType,
- implment getTgtMemIntrinsic() in SPIRVISelLowering,
- add hasSideEffects = 0 in Pseudo (SPIRVInstrFormats.td),
- add legalization rule for G_MEMSET, correct G_BRCOND rule,
- add capability processing for OpBuildNDRange in SPIRVModuleAnalysis,
- don't correct types of registers holding constants and used in
G_ADDRSPACE_CAST (SPIRVPreLegalizer.cpp),
- lower memset/bswap intrinsics to functions in SPIRVPrepareFunctions,
- change TargetLoweringObjectFileELF to SPIRVTargetObjectFile
in SPIRVTargetMachine.cpp,
- correct comments.
5 LIT tests are added to show the improvement.
Differential Revision: https://reviews.llvm.org/D133253
Co-authored-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
Co-authored-by: Michal Paszkowski <michal.paszkowski@outlook.com>
Co-authored-by: Andrey Tretyakov <andrey1.tretyakov@intel.com>
Co-authored-by: Konrad Trifunovic <konrad.trifunovic@intel.com>
The patch contains target lowering for SPIRV. Also it implements
TargetMachine and AsmPrinter.
Differential Revision: https://reviews.llvm.org/D116463
Authors: Aleksandr Bezzubikov, Lewis Crawford, Ilia Diachkov,
Michal Paszkowski, Andrey Tretyakov, Konrad Trifunovic
Co-authored-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
Co-authored-by: Ilia Diachkov <iliya.diyachkov@intel.com>
Co-authored-by: Michal Paszkowski <michal.paszkowski@outlook.com>
Co-authored-by: Andrey Tretyakov <andrey1.tretyakov@intel.com>
Co-authored-by: Konrad Trifunovic <konrad.trifunovic@intel.com>
