https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118673
Bug ID: 118673
Summary: [14/15 regression] LLVM's libMLIR miscompiled since
r14-1705-g2764335bd336f2
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
Target Milestone: ---
Created attachment 60293
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=60293&action=edit
IntegerDotProductOps.cpp.ii.gz
Originally reported in LLVM over at
https://github.com/llvm/llvm-project/issues/124410.
I don't have a standalone runtime testcase though.
The relevant snippet is:
```
template <typename IntegerDotProductOpTy>
static SmallVector<ArrayRef<spirv::Capability>, 1>
getIntegerDotProductCapabilities(Operation *op) {
// Requires the the DotProduct capability and capabilities that depend on
// exact op types.
static const auto dotProductCap = spirv::Capability::DotProduct;
static const auto dotProductInput4x8BitPackedCap =
spirv::Capability::DotProductInput4x8BitPacked;
static const auto dotProductInput4x8BitCap =
spirv::Capability::DotProductInput4x8Bit;
static const auto dotProductInputAllCap =
spirv::Capability::DotProductInputAll;
SmallVector<ArrayRef<spirv::Capability>, 1> capabilities = {dotProductCap};
Type factorTy = op->getOperand(0).getType();
StringAttr packedVectorFormatAttrName =
IntegerDotProductOpTy::getFormatAttrName(op->getName());
if (auto intTy = llvm::dyn_cast<IntegerType>(factorTy)) {
auto formatAttr = llvm::cast<spirv::PackedVectorFormatAttr>(
op->getAttr(packedVectorFormatAttrName));
if (formatAttr.getValue() ==
spirv::PackedVectorFormat::PackedVectorFormat4x8Bit)
capabilities.push_back(dotProductInput4x8BitPackedCap);
return capabilities;
}
auto vecTy = llvm::cast<VectorType>(factorTy);
if (vecTy.getElementTypeBitWidth() == 8) {
capabilities.push_back(dotProductInput4x8BitCap);
return capabilities;
}
capabilities.push_back(dotProductInputAllCap);
return capabilities;
}
SmallVector<ArrayRef<spirv::Capability>, 1> UDotAccSatOp::getCapabilities() {
return getIntegerDotProductCapabilities<UDotAccSatOp>(*this);
}
```
Before/after r14-1705-g2764335bd336f2, the only difference (with some prints
added) is:
```
│ Disassembly of section
.text._ZN4mlir5spirvL30getIntegerDotProductExtensionsEv:
│
│ 0000000000000000 <mlir::spirv::getIntegerDotProductExtensions()>:
│ mlir::spirv::getIntegerDotProductExtensions():
│ - lea 0x10(%rdi),%rdx
│ - lea 0x0(%rip),%rcx
│ - R_X86_64_PC32
.rodata._ZZN4mlir5spirvL30getIntegerDotProductExtensionsEvE9extension-0x4
│ + lea -0xc(%rsp),%rdx
│ + lea 0x10(%rdi),%rcx
│ mov %rdi,%rax
│ movabs $0x100000001,%rsi
│ - mov %rdx,(%rdi)
│ - mov %rcx,0x10(%rdi)
│ + mov %rcx,(%rdi)
│ + mov %rdx,0x10(%rdi)
│ movq $0x1,0x18(%rdi)
│ mov
```
The file was built with:
```
$ g++ -DGTEST_HAS_RTTI=0 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS
-D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
-I/home/sam/llvm/llvm-project/build-bad-after/tools/mlir/lib/Dialect/SPIRV/IR
-I/home/sam/llvm/llvm-project/mlir/lib/Dialect/SPIRV/IR
-I/home/sam/llvm/llvm-project/build-bad-after/tools/mlir/include
-I/home/sam/llvm/llvm-project/mlir/include
-I/home/sam/llvm/llvm-project/build-bad-after/include
-I/home/sam/llvm/llvm-project/llvm/include -fPIC -fno-semantic-interposition
-fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra
-Wno-unused-parameter -Wwrite-strings -Wcast-qual
-Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough
-Wno-maybe-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move
-Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor
-Wsuggest-override -Wno-comment -Wno-misleading-indentation
-Wctad-maybe-unsupported -ffunction-sections -fdata-sections -Wundef -Os
-DNDEBUG -std=c++17 -fno-exceptions -funwind-tables -fno-rtti -MD -MT
tools/mlir/lib/Dialect/SPIRV/IR/CMakeFiles/obj.MLIRSPIRVDialect.dir/IntegerDotProductOps.cpp.o
-MF CMakeFiles/obj.MLIRSPIRVDialect.dir/IntegerDotProductOps.cpp.o.d -o
CMakeFiles/obj.MLIRSPIRVDialect.dir/IntegerDotProductOps.cpp.o -c
/home/sam/llvm/llvm-project/mlir/lib/Dialect/SPIRV/IR/IntegerDotProductOps.cpp
-save-temps
```
