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[MLIR][MemRefToLLVM] Fix atomic_rmw lowering for floats#2

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[MLIR][MemRefToLLVM] Fix atomic_rmw lowering for floats#2
google-labs-jules[bot] wants to merge 1 commit intomainfrom
users/Men-cotton/mlir/64493

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Implemented support for floating-point memref.generic_atomic_rmw in MemRefToLLVM conversion by bitcasting to integers for cmpxchg.


PR created automatically by Jules for task 157868145251552990 started by @Men-cotton

Currently `memref.generic_atomic_rmw` crashes during conversion to LLVM IR
when the element type is a floating-point type, because `llvm.cmpxchg` only
supports integer and pointer operands.

This patch updates `GenericAtomicRMWOpLowering` to detect floating-point types
and bitcast operands to the corresponding integer type (e.g., `f32` -> `i32`)
before creating the `cmpxchg` instruction. It also bitcasts the result back to
float for the loop continuation and operation replacement.

Added a regression test `mlir/test/Conversion/MemRefToLLVM/generic-atomic-rmw-flt.mlir`.
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@Men-cotton Men-cotton closed this Dec 1, 2025
Men-cotton pushed a commit that referenced this pull request Dec 9, 2025
… errors (llvm#169989)

We can see the following while running clang-repl in C mode 
```
anutosh491@vv-nuc:/build/anutosh491/llvm-project/build/bin$ ./clang-repl --Xcc=-x --Xcc=c --Xcc=-std=c23
clang-repl> printf("hi\n");
In file included from <<< inputs >>>:1:
input_line_1:1:1: error: call to undeclared library function 'printf' with type 'int (const char *, ...)'; ISO C99 and
      later do not support implicit function declarations [-Wimplicit-function-declaration]
    1 | printf("hi\n");
      | ^
input_line_1:1:1: note: include the header <stdio.h> or explicitly provide a declaration for 'printf'
error: Parsing failed.
clang-repl> #include <stdio.h>
hi
```

In debug mode while dumping the generated Module, i see this 
```
clang-repl> printf("hi\n");
In file included from <<< inputs >>>:1:
input_line_1:1:1: error: call to undeclared library function 'printf' with type 'int (const char *, ...)'; ISO C99 and
      later do not support implicit function declarations [-Wimplicit-function-declaration]
    1 | printf("hi\n");
      | ^
input_line_1:1:1: note: include the header <stdio.h> or explicitly provide a declaration for 'printf'
error: Parsing failed.
clang-repl> #include <stdio.h>

=== compile-ptu 1 ===
[TU=0x55556cfbf830, M=0x55556cfc13a0 (incr_module_1)]
[LLVM IR]
; ModuleID = 'incr_module_1'
source_filename = "incr_module_1"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

@.str = private unnamed_addr constant [4 x i8] c"hi\0A\00", align 1
@llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__sub_I_incr_module_1, ptr null }]

define internal void @__stmts__0() #0 {
entry:
  %call = call i32 (ptr, ...) @printf(ptr noundef @.str)
  ret void
}

declare i32 @printf(ptr noundef, ...) #1

; Function Attrs: noinline nounwind uwtable
define internal void @_GLOBAL__sub_I_incr_module_1() #2 section ".text.startup" {
entry:
  call void @__stmts__0()
  ret void
}

attributes #0 = { "min-legal-vector-width"="0" }
attributes #1 = { "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #2 = { noinline nounwind uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }

!llvm.module.flags = !{!0, !1, !2, !3, !4}
!llvm.ident = !{!5}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{i32 7, !"frame-pointer", i32 2}
!5 = !{!"clang version 22.0.0git (https://github.com/anutosh491/llvm-project.git 81ad8fb)"}
=== end compile-ptu ===

execute-ptu 1: [TU=0x55556cfbf830, M=0x55556cfc13a0 (incr_module_1)]
hi
```

Basically I see that CodeGen emits IR for a cell before we know whether
DiagnosticsEngine has an error. For C code like `printf("hi\n");`
without <stdio.h>, Sema emits a diagnostic but still produces a
"codegen-able" `TopLevelStmt`, so the `printf` call is IR-generated into
the current module.

Previously, when `Diags.hasErrorOccurred()` was true, we only cleaned up
the PTU AST and left the CodeGen module untouched. The next successful
cell then called `GenModule()`, which returned that same module (now
also containing the next cell’s IR), causing side effects from the
failed cell (e.g. printf)
Men-cotton pushed a commit that referenced this pull request Dec 24, 2025
…lvm#159480)

When building rustc std for arm64e, core fails to compile successfully
with the error:
```
Constant ValueID not recognized.
UNREACHABLE executed at rust/src/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:523!
```

This is a result of function merging so I modified
FunctionComparator.cpp as the ConstantPtrAuth value would go unchecked
in the switch statement.

The test case is a reduction from the failure in core and fails on main
with:
```
********************
FAIL: LLVM :: Transforms/MergeFunc/ptrauth-const-compare.ll (59809 of 59995)
******************** TEST 'LLVM :: Transforms/MergeFunc/ptrauth-const-compare.ll' FAILED ********************
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 3
/Users/oskarwirga/llvm-project/build/bin/opt -S -passes=mergefunc < /Users/oskarwirga/llvm-project/llvm/test/Transforms/MergeFunc/ptrauth-const-compare.ll | /Users/oskarwirga/llvm-project/build/bin/FileCheck /Users/oskarwirga/llvm-project/llvm/test/Transforms/MergeFunc/ptrauth-const-compare.ll
# executed command: /Users/oskarwirga/llvm-project/build/bin/opt -S -passes=mergefunc
# .---command stderr------------
# | Constant ValueID not recognized.
# | UNREACHABLE executed at /Users/oskarwirga/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:523!
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
# | Stack dump:
# | 0.	Program arguments: /Users/oskarwirga/llvm-project/build/bin/opt -S -passes=mergefunc
# | 1.	Running pass "mergefunc" on module "<stdin>"
# |  #0 0x0000000103335770 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102651770)
# |  #1 0x00000001033336bc llvm::sys::RunSignalHandlers() (/Users/oskarwirga/llvm-project/build/bin/opt+0x10264f6bc)
# |  #2 0x0000000103336218 SignalHandler(int, __siginfo*, void*) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102652218)
# |  #3 0x000000018e6c16a4 (/usr/lib/system/libsystem_platform.dylib+0x1804ad6a4)
# |  #4 0x000000018e68788c (/usr/lib/system/libsystem_pthread.dylib+0x18047388c)
# |  llvm#5 0x000000018e590a3c (/usr/lib/system/libsystem_c.dylib+0x18037ca3c)
# |  llvm#6 0x00000001032a84bc llvm::install_out_of_memory_new_handler() (/Users/oskarwirga/llvm-project/build/bin/opt+0x1025c44bc)
# |  llvm#7 0x00000001033b37c0 llvm::FunctionComparator::cmpMDNode(llvm::MDNode const*, llvm::MDNode const*) const (/Users/oskarwirga/llvm-project/build/bin/opt+0x1026cf7c0)
# |  llvm#8 0x00000001033b4d90 llvm::FunctionComparator::cmpBasicBlocks(llvm::BasicBlock const*, llvm::BasicBlock const*) const (/Users/oskarwirga/llvm-project/build/bin/opt+0x1026d0d90)
# |  llvm#9 0x00000001033b5234 llvm::FunctionComparator::compare() (/Users/oskarwirga/llvm-project/build/bin/opt+0x1026d1234)
# | llvm#10 0x0000000102d6d868 (anonymous namespace)::MergeFunctions::insert(llvm::Function*) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102089868)
# | llvm#11 0x0000000102d6bc0c llvm::MergeFunctionsPass::runOnModule(llvm::Module&) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102087c0c)
# | llvm#12 0x0000000102d6b430 llvm::MergeFunctionsPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102087430)
# | llvm#13 0x0000000102b90558 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/Users/oskarwirga/llvm-project/build/bin/opt+0x101eac558)
# | llvm#14 0x0000000103734bc4 llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::ArrayRef<std::__1::function<void (llvm::PassBuilder&)>>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool, bool) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102a50bc4)
# | llvm#15 0x000000010373cc28 optMain (/Users/oskarwirga/llvm-project/build/bin/opt+0x102a58c28)
# | llvm#16 0x000000018e2e6b98
# `-----------------------------
# error: command failed with exit status: -6
# executed command: /Users/oskarwirga/llvm-project/build/bin/FileCheck /Users/oskarwirga/llvm-project/llvm/test/Transforms/MergeFunc/ptrauth-const-compare.ll
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  /Users/oskarwirga/llvm-project/build/bin/FileCheck /Users/oskarwirga/llvm-project/llvm/test/Transforms/MergeFunc/ptrauth-const-compare.ll
# `-----------------------------
# error: command failed with exit status: 2
```
Men-cotton pushed a commit that referenced this pull request Jan 5, 2026
CHR builds the merged hot-path predicate with
IRBuilder::CreateLogicalAnd. That helper is implemented as a select and
can constant-fold to a non- Instruction (e.g. i1 true). The pass then
attempted to mark the merged condition as having explicitly unknown
branch weights when profile data is present, but it unconditionally did
cast<Instruction>(MergedCondition), which can crash in release builds.

Guard the metadata update with dyn_cast<Instruction> and pass the
containing Function explicitly to avoid calling Instruction::getFunction
when the value is not attached yet.

Add a regression test that exercises the constant-folding case.

Crashing stack:

```
  2.      Running pass "chr" on function "repro_crash"
  #0 0x0000000003be00a4 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (bin/opt+0x3be00a4)
  #1 0x0000000003bdd9e8 llvm::sys::RunSignalHandlers() (bin/opt+0x3bdd9e8)
  #2 0x0000000003be1300 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
  #3 0x0000ffffa8e1d840 (linux-vdso.so.1+0x840)
  #4 0x0000000003c815e0 llvm::Instruction::getFunction() const (bin/opt+0x3c815e0)
  llvm#5 0x0000000003dcd35c llvm::setExplicitlyUnknownBranchWeightsIfProfiled(llvm::Instruction&, llvm::StringRef, llvm::Function const*) (bin/opt+0x3dcd35c)
  llvm#6 0x0000000004fb3670 (anonymous namespace)::CHR::addToMergedCondition(bool, llvm::Value*, llvm::Instruction*, (anonymous namespace)::CHRScope*, llvm::IRBuilder<llvm::ConstantFolder, llvm::IRBuilderDefaultInserter>&, llvm::Value*&) ControlHeightReduction.cpp:0:0
  llvm#7 0x0000000004fa7d88 (anonymous namespace)::CHR::run() ControlHeightReduction.cpp:0:0
  llvm#8 0x0000000004fa3618 llvm::ControlHeightReductionPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (bin/opt+0x4fa3618)
```

Tests: opt <
llvm/test/Transforms/PGOProfile/chr-unknown-profdata-crash.ll
-passes='require<profile-summary>,function(chr)' -force-chr
-chr-merge-threshold=1 -disable-output
Men-cotton pushed a commit that referenced this pull request Jan 5, 2026
…ng destructor (llvm#174082)"

This reverts commit 7976ac9.

This is causing msan failures. msan-track-origins stack trace:

==9441==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x55c20df74ad3 in clang::interp::Pointer::operator=(clang::interp::Pointer&&) llvm-project/clang/lib/AST/ByteCode/Pointer.cpp:137:7
    #1 0x55c20db81010 in bool clang::interp::InitGlobal<(clang::interp::PrimType)13, clang::interp::Pointer>(clang::interp::InterpState&, clang::interp::CodePtr, unsigned int) llvm-project/clang/lib/AST/ByteCode/Interp.h:1478:16
    #2 0x55c20db7ec56 in emitInitGlobalPtr blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/_virtual_includes/ast_bytecode_opcodes_gen/Opcodes.inc:26162:10
    #3 0x55c20db7ec56 in clang::interp::EvalEmitter::emitInitGlobal(clang::interp::PrimType, unsigned int, clang::interp::SourceInfo) blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/_virtual_includes/ast_bytecode_opcodes_gen/Opcodes.inc:26042:12
    #4 0x55c20da58b87 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitVarDecl(clang::VarDecl const*, clang::Expr const*, bool, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4924:20
    llvm#5 0x55c20da64a61 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitDeclAndReturn(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4831:14
    llvm#6 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    llvm#7 0x55c20d970d23 in clang::interp::Context::evaluateAsInitializer(clang::interp::State&, clang::VarDecl const*, clang::Expr const*, clang::APValue&) llvm-project/clang/lib/AST/ByteCode/Context.cpp:141:16
    llvm#8 0x55c20e25b8de in clang::Expr::EvaluateAsInitializer(clang::APValue&, clang::ASTContext const&, clang::VarDecl const*, llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/ExprConstant.cpp:20754:20
    llvm#9 0x55c20da368d5 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitDeclRef(clang::ValueDecl const*, clang::Expr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:7162:19
    llvm#10 0x55c20da34986 in clang::interp::Compiler<clang::interp::EvalEmitter>::VisitDeclRefExpr(clang::DeclRefExpr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:7192:16
    llvm#11 0x55c20da66666 in clang::StmtVisitorBase<llvm::make_const_ptr, clang::interp::Compiler<clang::interp::EvalEmitter>, bool>::Visit(clang::Stmt const*) blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/include/clang/AST/StmtNodes.inc:474:1
    llvm#12 0x55c20da65d3f in clang::interp::Compiler<clang::interp::EvalEmitter>::visit(clang::Expr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4293:16
    llvm#13 0x55c20da57348 in clang::interp::Compiler<clang::interp::EvalEmitter>::VisitCXXTypeidExpr(clang::CXXTypeidExpr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:3893:14
    llvm#14 0x55c20da66760 in clang::StmtVisitorBase<llvm::make_const_ptr, clang::interp::Compiler<clang::interp::EvalEmitter>, bool>::Visit(clang::Stmt const*) blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/include/clang/AST/StmtNodes.inc:658:1
    llvm#15 0x55c20da65d3f in clang::interp::Compiler<clang::interp::EvalEmitter>::visit(clang::Expr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4293:16
    llvm#16 0x55c20da58afc in clang::interp::Compiler<clang::interp::EvalEmitter>::visitVarDecl(clang::VarDecl const*, clang::Expr const*, bool, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4921:18
    llvm#17 0x55c20da64a61 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitDeclAndReturn(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4831:14
    llvm#18 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    llvm#19 0x55c20d970d23 in clang::interp::Context::evaluateAsInitializer(clang::interp::State&, clang::VarDecl const*, clang::Expr const*, clang::APValue&) llvm-project/clang/lib/AST/ByteCode/Context.cpp:141:16
    llvm#20 0x55c20e25b8de in clang::Expr::EvaluateAsInitializer(clang::APValue&, clang::ASTContext const&, clang::VarDecl const*, llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/ExprConstant.cpp:20754:20
    llvm#21 0x55c20dfdcc38 in clang::VarDecl::evaluateValueImpl(llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/Decl.cpp:2608:23
    llvm#22 0x55c20dfdd1a2 in clang::VarDecl::checkForConstantInitialization(llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&) const llvm-project/clang/lib/AST/Decl.cpp:2687:7
    llvm#23 0x55c20b9154da in clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) llvm-project/clang/lib/Sema/SemaDecl.cpp:14941:27
    llvm#24 0x55c20b910f36 in clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) llvm-project/clang/lib/Sema/SemaDecl.cpp:14280:3
    llvm#25 0x55c20ad044ee in clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2639:17
    llvm#26 0x55c20acfe9f8 in clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2356:7
    llvm#27 0x55c20abd8a43 in clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1181:10
    llvm#28 0x55c20abd7654 in clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1203:12
    llvm#29 0x55c20abd4d9c in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp:1031:14
    llvm#30 0x55c20ac96f31 in clang::Parser::ParseInnerNamespace(llvm::SmallVector<clang::Parser::InnerNamespaceInfo, 4u> const&, unsigned int, clang::SourceLocation&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:240:7
    llvm#31 0x55c20ac950c7 in clang::Parser::ParseNamespace(clang::DeclaratorContext, clang::SourceLocation&, clang::SourceLocation) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:218:3
    llvm#32 0x55c20acfb09b in clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) llvm-project/clang/lib/Parse/ParseDecl.cpp:1909:12
    llvm#33 0x55c20abd3f88 in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp
    llvm#34 0x55c20abcfe33 in clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) llvm-project/clang/lib/Parse/Parser.cpp:744:12
    llvm#35 0x55c20abb214e in clang::ParseAST(clang::Sema&, bool, bool) llvm-project/clang/lib/Parse/ParseAST.cpp:170:20
    llvm#36 0x55c20a90adaa in clang::ASTFrontendAction::ExecuteAction() llvm-project/clang/lib/Frontend/FrontendAction.cpp:1432:3
    llvm#37 0x55c20a9095bf in clang::FrontendAction::Execute() llvm-project/clang/lib/Frontend/FrontendAction.cpp:1312:3
    llvm#38 0x55c20a76cdc7 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) llvm-project/clang/lib/Frontend/CompilerInstance.cpp:1004:33
    llvm#39 0x55c20805aab0 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:310:25
    llvm#40 0x55c20802e823 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) llvm-project/clang/tools/driver/cc1_main.cpp:304:15
    llvm#41 0x55c2080218ec in ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) llvm-project/clang/tools/driver/driver.cpp:225:12
    llvm#42 0x55c20801ea91 in clang_main(int, char**, llvm::ToolContext const&) llvm-project/clang/tools/driver/driver.cpp:268:12
    llvm#43 0x55c20801a6af in main blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/clang-driver.cpp:17:10
    llvm#44 0x7f79c4214351 in __libc_start_main (/usr/libc/lib64/libc.so.6+0x61351) (BuildId: ca23ec6d935352118622ce674a8bb52d)
    llvm#45 0x55c207f8c2e9 in _start /usr/libc/debug-src/src/csu/../sysdeps/x86_64/start.S:120

  Member fields were destroyed
    #0 0x55c207f9f5fd in __sanitizer_dtor_callback_fields llvm-project/compiler-rt/lib/msan/msan_interceptors.cpp:1074:5
    #1 0x55c20df74380 in ~Pointer llvm-project/clang/lib/AST/ByteCode/Pointer.h:826:12
    #2 0x55c20df74380 in clang::interp::Pointer::~Pointer() llvm-project/clang/lib/AST/ByteCode/Pointer.cpp:93:1
    #3 0x55c20da7c5ab in void dtorTy<clang::interp::Pointer>(clang::interp::Block*, std::byte*, clang::interp::Descriptor const*) llvm-project/clang/lib/AST/ByteCode/Descriptor.cpp:49:32
    #4 0x55c20d976b91 in clang::interp::Block::invokeDtor() llvm-project/clang/lib/AST/ByteCode/InterpBlock.h:149:7
    llvm#5 0x55c20da651a1 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitDeclAndReturn(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4869:22
    llvm#6 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    llvm#7 0x55c20d970d23 in clang::interp::Context::evaluateAsInitializer(clang::interp::State&, clang::VarDecl const*, clang::Expr const*, clang::APValue&) llvm-project/clang/lib/AST/ByteCode/Context.cpp:141:16
    llvm#8 0x55c20e25b8de in clang::Expr::EvaluateAsInitializer(clang::APValue&, clang::ASTContext const&, clang::VarDecl const*, llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/ExprConstant.cpp:20754:20
    llvm#9 0x55c20dfdcc38 in clang::VarDecl::evaluateValueImpl(llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/Decl.cpp:2608:23
    llvm#10 0x55c20dfdd1a2 in clang::VarDecl::checkForConstantInitialization(llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&) const llvm-project/clang/lib/AST/Decl.cpp:2687:7
    llvm#11 0x55c20b9154da in clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) llvm-project/clang/lib/Sema/SemaDecl.cpp:14941:27
    llvm#12 0x55c20b910f36 in clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) llvm-project/clang/lib/Sema/SemaDecl.cpp:14280:3
    llvm#13 0x55c20ad044ee in clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2639:17
    llvm#14 0x55c20acfe9f8 in clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2356:7
    llvm#15 0x55c20abd8a43 in clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1181:10
    llvm#16 0x55c20abd7654 in clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1203:12
    llvm#17 0x55c20abd4d9c in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp:1031:14
    llvm#18 0x55c20ac96f31 in clang::Parser::ParseInnerNamespace(llvm::SmallVector<clang::Parser::InnerNamespaceInfo, 4u> const&, unsigned int, clang::SourceLocation&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:240:7
    llvm#19 0x55c20ac950c7 in clang::Parser::ParseNamespace(clang::DeclaratorContext, clang::SourceLocation&, clang::SourceLocation) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:218:3
    llvm#20 0x55c20acfb09b in clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) llvm-project/clang/lib/Parse/ParseDecl.cpp:1909:12
Men-cotton pushed a commit that referenced this pull request Jan 14, 2026
…lvm#175807)

A buildbot was failing with a use-after-poison
(https://lab.llvm.org/buildbot/#/builders/24/builds/16530) after
llvm#175050:
```
==llc==1532559==ERROR: AddressSanitizer: use-after-poison on address 0xe26e74e12368 at pc 0xb36d41bd74dc bp 0xffffed72a450 sp 0xffffed72a448
READ of size 8 at 0xe26e74e12368 thread T0
    #0 0xb36d41bd74d8 in llvm::MachineInstr::print(llvm::raw_ostream&, bool, bool, bool, bool, llvm::TargetInstrInfo const*) const /home/b/sanitizer-aarch64-linux-bootstrap-asan/build/llvm-project/llvm/lib/CodeGen/MachineInstr.cpp:1796:35
    #1 0xb36d3e221b08 in operator<< /home/b/sanitizer-aarch64-linux-bootstrap-asan/build/llvm-project/llvm/include/llvm/CodeGen/MachineInstr.h:2150:6
    #2 0xb36d3e221b08 in llvm::PreRARematStage::rollback(llvm::PreRARematStage::RollbackInfo const&, llvm::BitVector&) const /home/b/sanitizer-aarch64-linux-bootstrap-asan/build/llvm-project/llvm/lib/Target/AMDGPU/GCNSchedStrategy.cpp:2363:57
...
```

This is because it was printing an instruction that had already been
deleted. This patch fixes this by reversing the order.
Men-cotton pushed a commit that referenced this pull request Feb 23, 2026
…er. (llvm#181941)

The progress event reporter has a thread that reports events every 250
millisecond. and is destroyed in its destructor.

When in event reporter desctructor, the event reporter may have pending
event but the call mutex is destroyed leading to the crash.

Relevant stack trace from CI.
```
[2026-02-13T17:46:13.577Z] libc++abi: terminating due to uncaught exception of type std::__1::system_error: mutex lock failed: Invalid argument 
[2026-02-13T17:46:13.577Z] PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash report from ~/Library/Logs/DiagnosticReports/. 

[2026-02-13T17:46:13.577Z]  #0 0x0000000102b6943c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x10008943c) 
[2026-02-13T17:46:13.577Z]  #1 0x0000000102b67368 llvm::sys::RunSignalHandlers() (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x100087368) 
[2026-02-13T17:46:13.577Z]  #2 0x0000000102b69f20 SignalHandler(int, __siginfo*, void*) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x100089f20)
[2026-02-13T17:46:13.577Z]  #3 0x000000018bbdb744 (/usr/lib/system/libsystem_platform.dylib+0x1804e3744) 
[2026-02-13T17:46:13.577Z]  #4 0x000000018bbd1888 (/usr/lib/system/libsystem_pthread.dylib+0x1804d9888) 
[2026-02-13T17:46:13.577Z]  llvm#5 0x000000018bad6850 (/usr/lib/system/libsystem_c.dylib+0x1803de850) 
[2026-02-13T17:46:13.577Z]  llvm#6 0x000000018bb85858 (/usr/lib/libc++abi.dylib+0x18048d858) 
[2026-02-13T17:46:13.577Z]  llvm#7 0x000000018bb744bc (/usr/lib/libc++abi.dylib+0x18047c4bc) 
[2026-02-13T17:46:13.577Z]  llvm#8 0x000000018b7a0424 (/usr/lib/libobjc.A.dylib+0x1800a8424) 
[2026-02-13T17:46:13.577Z]  llvm#9 0x000000018bb84c2c (/usr/lib/libc++abi.dylib+0x18048cc2c) 
[2026-02-13T17:46:13.577Z] llvm#10 0x000000018bb88394 (/usr/lib/libc++abi.dylib+0x180490394) 
[2026-02-13T17:46:13.577Z] llvm#11 0x000000018bb8833c (/usr/lib/libc++abi.dylib+0x18049033c) 
[2026-02-13T17:46:13.577Z] llvm#12 0x000000018bb01b90 (/usr/lib/libc++.1.dylib+0x180409b90) 
[2026-02-13T17:46:13.577Z] llvm#13 0x000000018bb01b34 (/usr/lib/libc++.1.dylib+0x180409b34) 
[2026-02-13T17:46:13.577Z] llvm#14 0x000000018bb038a0 (/usr/lib/libc++.1.dylib+0x18040b8a0) 
[2026-02-13T17:46:13.577Z] llvm#15 0x0000000102b6fbac lldb_dap::DAP::Send(std::__1::variant<lldb_dap::protocol::Request, lldb_dap::protocol::Response, lldb_dap::protocol::Event> const&) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x10008fbac) 
[2026-02-13T17:46:13.577Z] llvm#16 0x0000000102b6f890 lldb_dap::DAP::SendJSON(llvm::json::Value const&) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x10008f890) 
[2026-02-13T17:46:13.577Z] llvm#17 0x0000000102b78788 std::__1::__function::__func<lldb_dap::DAP::DAP(lldb_dap::Log&, lldb_dap::ReplMode, std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>>>, bool, llvm::StringRef, lldb_private::transport::JSONTransport<lldb_dap::ProtocolDescriptor>&, lldb_private::MainLoopPosix&)::$_0, std::__1::allocator<lldb_dap::DAP::DAP(lldb_dap::Log&, lldb_dap::ReplMode, std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>>>, bool, llvm::StringRef, lldb_private::transport::JSONTransport<lldb_dap::ProtocolDescriptor>&, lldb_private::MainLoopPosix&)::$_0>, void (lldb_dap::ProgressEvent&)>::operator()(lldb_dap::ProgressEvent&) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x100098788) 
[2026-02-13T17:46:13.577Z] llvm#18 0x0000000102b8939c lldb_dap::ProgressEventManager::ReportIfNeeded() (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x1000a939c) 
[2026-02-13T17:46:13.577Z] llvm#19 0x0000000102b8982c lldb_dap::ProgressEventReporter::ReportStartEvents() (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x1000a982c) 
[2026-02-13T17:46:13.577Z] llvm#20 0x0000000102b8a038 void* std::__1::__thread_proxy[abi:nn200100]<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct>>, lldb_dap::ProgressEventReporter::ProgressEventReporter(std::__1::function<void (lldb_dap::ProgressEvent&)>)::$_0>>(void*) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x1000aa038) 
[2026-02-13T17:46:13.577Z] llvm#21 0x000000018bbd1c08 (/usr/lib/system/libsystem_pthread.dylib+0x1804d9c08) [2026-02-13T17:46:13.577Z] llvm#22 0x000000018bbccba8 (/usr/lib/system/libsystem_pthread.dylib+0x1804d4ba8)
```
rdar://170331108
Men-cotton pushed a commit that referenced this pull request Feb 23, 2026
I created an issue about this in llvm#179976.

Clang's Address Sanitizer installs its own SEH filter which handles some
types of uncaught exceptions. Along with register values and some other
information, it also generates a stack trace. However, current logic is
incomplete. It relies on DbgHelp's SymFunctionTableAccess64 and
SymGetModuleBase64 which won't work with machine code that has its
RUNTIME_FUNCTION entry registered with Rtl* (e.g. RtlAddFunctionTable)
system calls. Most likely, this is because DbgHelp either relies on
information in PDB files or considers PDATA and XDATA only from loaded
EXE and DLL modules. Either way, consider the following example:

```
#include <windows.h>
#include <iostream>
#include <vector>

typedef union _UNWIND_CODE {
    struct {
        BYTE CodeOffset;
        BYTE UnwindOp : 4;
        BYTE OpInfo : 4;
    };
    USHORT FrameOffset;
} UNWIND_CODE, * PUNWIND_CODE;

typedef struct _UNWIND_INFO {
    BYTE Version : 3;
    BYTE Flags : 5;
    BYTE SizeOfProlog;
    BYTE CountOfCodes;
    BYTE FrameRegister : 4;
    BYTE FrameOffset : 4;
    UNWIND_CODE UnwindCode[1]; // Variable size
} UNWIND_INFO, * PUNWIND_INFO;

#define UWOP_PUSH_NONVOL      0
#define UWOP_ALLOC_LARGE      1
#define UWOP_ALLOC_SMALL      2
#define UWOP_SET_FPREG        3
#define UWOP_SAVE_NONVOL      4
#define UWOP_SAVE_NONVOL_FAR  5
#define UWOP_SAVE_XMM128      8
#define UWOP_SAVE_XMM128_FAR  9
#define UWOP_PUSH_MACHFRAME   10

int main() {
    // PUSH RBX         (0x53)                - Save non-volatile register
    // SUB RSP, 0x20    (0x48 0x83 0xEC 0x20) - Allocate 32 bytes (shadow space)
    // XOR RAX, RAX     (0x48 0x31 0xC0)      - Zero out RAX
    // MOV RAX, [RAX]   (0x48 0x8B 0x00)      - Dereference NULL
    
    std::vector<unsigned char> code = {
        0x53,
        0x48, 0x83, 0xEC, 0x20,
        0x48, 0x31, 0xC0,
        0x48, 0x8B, 0x00
    };

    size_t codeSize = code.size();
    size_t totalSize = 100;

    LPVOID pMemory = VirtualAlloc(NULL, totalSize, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
    
    BYTE* pCodeBase = (BYTE*)pMemory;
    PUNWIND_INFO pUnwindInfo = (PUNWIND_INFO)(pCodeBase + codeSize);    

    size_t alignmentPadding = 0;
    if ((size_t)pUnwindInfo % 4 != 0) {
        alignmentPadding = 4 - ((size_t)pUnwindInfo % 4);
        pUnwindInfo = (PUNWIND_INFO)((BYTE*)pUnwindInfo + alignmentPadding);
    }

    memcpy(pCodeBase, code.data(), codeSize);

    pUnwindInfo->Version = 1;
    pUnwindInfo->Flags = UNW_FLAG_NHANDLER;
    pUnwindInfo->Flags = 0; 
    pUnwindInfo->SizeOfProlog = 5; 
    pUnwindInfo->CountOfCodes = 2; 
    pUnwindInfo->FrameRegister = 0;
    pUnwindInfo->FrameOffset = 0;

    pUnwindInfo->UnwindCode[0].CodeOffset = 5;
    pUnwindInfo->UnwindCode[0].UnwindOp = UWOP_ALLOC_SMALL;
    pUnwindInfo->UnwindCode[0].OpInfo = 3; 

    pUnwindInfo->UnwindCode[1].CodeOffset = 1;
    pUnwindInfo->UnwindCode[1].UnwindOp = UWOP_PUSH_NONVOL;
    pUnwindInfo->UnwindCode[1].OpInfo = 3; // RBX

    RUNTIME_FUNCTION tableEntry = {};
    tableEntry.BeginAddress = 0;
    tableEntry.EndAddress = (DWORD)codeSize;
    tableEntry.UnwindData = (DWORD)((BYTE*)pUnwindInfo - (BYTE*)pMemory);

    DWORD64 baseAddress = (DWORD64)pMemory;
    RtlAddFunctionTable(&tableEntry, 1, baseAddress);

    typedef void(*FuncType)();
    FuncType myFunc = (FuncType)pMemory;
    myFunc();

    return 0;
}
```

Windows' kernel can propagate hardware exception through that function,
so clearly these entries are at least partially correct. Right now,
ASan's stack walking produces this (compiled with latest release,
clang++):

```
PS D:\Local Projects\cpp-playground> ./a.exe
=================================================================
==14216==ERROR: AddressSanitizer: access-violation on unknown address 0x000000000000 (pc 0x0199561c0008 bp 0x004cf0cffb30 sp 0x004cf0cff970 T0)
==14216==The signal is caused by a READ memory access.
==14216==Hint: address points to the zero page.
    #0 0x0199561c0007  (<unknown module>)
    #1 0x000000000000  (<unknown module>)
    #2 0x000000000000  (<unknown module>)

==14216==Register values:
rax = 0  rbx = 4cf0cffaa0  rcx = 7ffcb97b4e28  rdx = 19955dc0000
rdi = 11bf564a0040  rsi = 0  rbp = 4cf0cffb30  rsp = 4cf0cff970
r8  = 7ffffffffffffffc  r9  = 1  r10 = 0  r11 = 246
r12 = 0  r13 = 0  r14 = 0  r15 = 0
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: access-violation (<unknown module>)
==14216==ABORTING
```

Frames one and two is just some stack space allocated by that dynamic
function. While patched version produces this:

```
PS D:\Local Projects\cpp-playground> ./a.exe
=================================================================
==13660==ERROR: AddressSanitizer: access-violation on unknown address 0x000000000000 (pc 0x01ed5ad70008 bp 0x00d76492f650 sp 0x00d76492f490 T0)
==13660==The signal is caused by a READ memory access.
==13660==Hint: address points to the zero page.
    #0 0x01ed5ad70007  (<unknown module>)
    #1 0x7ff732e518a1 in main (D:\Local Projects\cpp-playground\a.exe+0x1400018a1)
    #2 0x7ff732e56a9b in invoke_main D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:78
    #3 0x7ff732e56a9b in __scrt_common_main_seh D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288
    #4 0x7ffcb878e8d6  (C:\WINDOWS\System32\KERNEL32.DLL+0x18002e8d6)
    llvm#5 0x7ffcb966c53b  (C:\WINDOWS\SYSTEM32\ntdll.dll+0x18008c53b)

==13660==Register values:
rax = 0  rbx = d76492f5c0  rcx = 7ffcb97b4e28  rdx = 1ed5a870000
rdi = 12135afa0040  rsi = 0  rbp = d76492f650  rsp = d76492f490
r8  = 7ffffffffffffffc  r9  = 1  r10 = 0  r11 = 246
r12 = 0  r13 = 0  r14 = 0  r15 = 0
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: access-violation (<unknown module>)
==13660==ABORTING
```

Now we see that stack walking handled our dynamic function properly.
Interestingly enough, it appears that other overloaded version of
UnwindSlow procedure that works without CONTEXT structure already has
some logic to handle this. Theoretically, symbolizer should also be able
to provide some information about these functions, but I don't think
that this is necessary.

I added SANITIZER_WINDOWS64 check because I am pretty sure Microsoft
only mentions these functions for 64 bit version of their OS. I also
can't check how this works on ARM.
Men-cotton pushed a commit that referenced this pull request Feb 28, 2026
Using code/ideas from the x86 backend to optimize a select on a bitcast
integer. The previous aarch64 approach was to individually extract the
bits from the mask, which is kind of terrible.

https://rust.godbolt.org/z/576sndT66

```llvm
define void @if_then_else8(ptr %out, i8 %mask, ptr %if_true, ptr %if_false) {
start:
  %t = load <8 x i32>, ptr %if_true, align 4
  %f = load <8 x i32>, ptr %if_false, align 4
  %m = bitcast i8 %mask to <8 x i1>
  %s = select <8 x i1> %m, <8 x i32> %t, <8 x i32> %f
  store <8 x i32> %s, ptr %out, align 4
  ret void
}
```

turned into 

```asm
if_then_else8:                          // @if_then_else8
        sub     sp, sp, llvm#16
        ubfx    w8, w1, #4, #1
        and     w11, w1, #0x1
        ubfx    w9, w1, llvm#5, #1
        fmov    s1, w11
        ubfx    w10, w1, #1, #1
        fmov    s0, w8
        ubfx    w8, w1, llvm#6, #1
        ldp     q5, q2, [x3]
        mov     v1.h[1], w10
        ldp     q4, q3, [x2]
        mov     v0.h[1], w9
        ubfx    w9, w1, #2, #1
        mov     v1.h[2], w9
        ubfx    w9, w1, #3, #1
        mov     v0.h[2], w8
        ubfx    w8, w1, llvm#7, #1
        mov     v1.h[3], w9
        mov     v0.h[3], w8
        ushll   v1.4s, v1.4h, #0
        ushll   v0.4s, v0.4h, #0
        shl     v1.4s, v1.4s, llvm#31
        shl     v0.4s, v0.4s, llvm#31
        cmlt    v1.4s, v1.4s, #0
        cmlt    v0.4s, v0.4s, #0
        bsl     v1.16b, v4.16b, v5.16b
        bsl     v0.16b, v3.16b, v2.16b
        stp     q1, q0, [x0]
        add     sp, sp, llvm#16
        ret
```

With this PR that instead emits

```asm
if_then_else8:
   adrp x8, .LCPI0_1
   dup v0.4s, w1
   ldr q1, [x8, :lo12:.LCPI0_1]
   adrp x8, .LCPI0_0
   ldr q2, [x8, :lo12:.LCPI0_0]
   ldp q4, q3, [x2]
   and v1.16b, v0.16b, v1.16b
   and v0.16b, v0.16b, v2.16b
   ldp q5, q2, [x3]
   cmeq v1.4s, v1.4s, #0
   cmeq v0.4s, v0.4s, #0
   bsl v1.16b, v2.16b, v3.16b
   bsl v0.16b, v5.16b, v4.16b
   stp q0, q1, [x0]
   ret
```

So substantially shorter. Instead of building the mask
element-by-element, this approach (by virtue of not splitting) instead
splats the mask value into all vector lanes, performs a bitwise and with
powers of 2, and compares with zero to construct the mask vector.

cc rust-lang/rust#122376
cc llvm#175769
Men-cotton pushed a commit that referenced this pull request Mar 12, 2026
`SE.getUMaxExpr` causes assertion failure due to type mismatch here:


https://github.com/llvm/llvm-project/blob/main/llvm/lib/Analysis/LoopAccessAnalysis.cpp#L253

Running `opt -S -p loop-vectorize -debug-only=loop-vectorize
llvm/test/Analysis/LoopAccessAnalysis/type-mismatch-in-scalar-evolution.ll
` without the changes made in LoopAccessAnalysis.cpp causes assertion
failure.
Attaching the stack dump for reference:
```
LV: Checking a loop in 'loop_contains_store_assumed_bounds' from input.ll
LV: Loop hints: force=? width=4 interleave=0
LV: Found a loop: for.body
LV: Found an induction variable.
opt: /home/kshitij/llvm-project/llvm/lib/Analysis/ScalarEvolution.cpp:3918: const llvm::SCEV* llvm::ScalarEvolution::getMinMaxExpr(llvm::SCEVTypes, llvm::SmallVectorImpl<const llvm::SCEV*>&): Assertion `getEffectiveSCEVType(Ops[i]->getType()) == ETy && "Operand types don't match!"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0.	Program arguments: opt -S -passes=loop-vectorize -debug-only=loop-vectorize -force-vector-width=4 -disable-output input.ll
1.	Running pass "function(loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>)" on module "input.ll"
2.	Running pass "loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>" on function "loop_contains_store_assumed_bounds"
 #0 0x000058ee97c5e652 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/local/bin/opt+0x4f44652)
 #1 0x000058ee97c5af0f llvm::sys::RunSignalHandlers() (/usr/local/bin/opt+0x4f40f0f)
 #2 0x000058ee97c5b05c SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #3 0x00007c49d4c45330 (/lib/x86_64-linux-gnu/libc.so.6+0x45330)
 #4 0x00007c49d4c9eb2c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 llvm#5 0x00007c49d4c9eb2c __pthread_kill_internal ./nptl/pthread_kill.c:78:10
 llvm#6 0x00007c49d4c9eb2c pthread_kill ./nptl/pthread_kill.c:89:10
 llvm#7 0x00007c49d4c4527e raise ./signal/../sysdeps/posix/raise.c:27:6
 llvm#8 0x00007c49d4c288ff abort ./stdlib/abort.c:81:7
 llvm#9 0x00007c49d4c2881b _nl_load_domain ./intl/loadmsgcat.c:1177:9
llvm#10 0x00007c49d4c3b517 (/lib/x86_64-linux-gnu/libc.so.6+0x3b517)
llvm#11 0x000058ee98003fdb llvm::ScalarEvolution::getMinMaxExpr(llvm::SCEVTypes, llvm::SmallVectorImpl<llvm::SCEV const*>&) (/usr/local/bin/opt+0x52e9fdb)
llvm#12 0x000058ee98004507 llvm::ScalarEvolution::getUMaxExpr(llvm::SCEV const*, llvm::SCEV const*) (/usr/local/bin/opt+0x52ea507)
llvm#13 0x000058ee980dc728 llvm::getStartAndEndForAccess(llvm::Loop const*, llvm::SCEV const*, llvm::Type*, llvm::SCEV const*, llvm::SCEV const*, llvm::ScalarEvolution*, llvm::DenseMap<std::pair<llvm::SCEV const*, llvm::Type*>, std::pair<llvm::SCEV const*, llvm::SCEV const*>, llvm::DenseMapInfo<std::pair<llvm::SCEV const*, llvm::Type*>, void>, llvm::detail::DenseMapPair<std::pair<llvm::SCEV const*, llvm::Type*>, std::pair<llvm::SCEV const*, llvm::SCEV const*>>>*, llvm::DominatorTree*, llvm::AssumptionCache*, std::optional<llvm::ScalarEvolution::LoopGuards>&) (/usr/local/bin/opt+0x53c2728)
llvm#14 0x000058ee9814008b llvm::isDereferenceableAndAlignedInLoop(llvm::LoadInst*, llvm::Loop*, llvm::ScalarEvolution&, llvm::DominatorTree&, llvm::AssumptionCache*, llvm::SmallVectorImpl<llvm::SCEVPredicate const*>*) (/usr/local/bin/opt+0x542608b)
llvm#15 0x000058ee9a0fa1ca llvm::LoopVectorizationLegality::canUncountableExitConditionLoadBeMoved(llvm::BasicBlock*) (/usr/local/bin/opt+0x73e01ca)
llvm#16 0x000058ee9a0faee0 llvm::LoopVectorizationLegality::isVectorizableEarlyExitLoop() (/usr/local/bin/opt+0x73e0ee0)
llvm#17 0x000058ee9a104678 llvm::LoopVectorizationLegality::canVectorize(bool) (/usr/local/bin/opt+0x73ea678)
llvm#18 0x000058ee9a08c953 llvm::LoopVectorizePass::processLoop(llvm::Loop*) (/usr/local/bin/opt+0x7372953)
llvm#19 0x000058ee9a090e21 llvm::LoopVectorizePass::runImpl(llvm::Function&) (/usr/local/bin/opt+0x7376e21)
llvm#20 0x000058ee9a0914e0 llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/usr/local/bin/opt+0x73774e0)
llvm#21 0x000058ee99e419a5 llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) PassBuilderPipelines.cpp:0:0
llvm#22 0x000058ee97f18905 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/usr/local/bin/opt+0x51fe905)
llvm#23 0x000058ee995d70d5 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) AMDGPUTargetMachine.cpp:0:0
llvm#24 0x000058ee97f17051 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/usr/local/bin/opt+0x51fd051)
llvm#25 0x000058ee995d7775 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) AMDGPUTargetMachine.cpp:0:0
llvm#26 0x000058ee97f1783d llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/usr/local/bin/opt+0x51fd83d)
llvm#27 0x000058ee9c153909 llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::ArrayRef<std::function<void (llvm::PassBuilder&)>>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool, bool) (/usr/local/bin/opt+0x9439909)
llvm#28 0x000058ee97c3f380 optMain (/usr/local/bin/opt+0x4f25380)
llvm#29 0x00007c49d4c2a1ca __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
llvm#30 0x00007c49d4c2a28b call_init ./csu/../csu/libc-start.c:128:20
llvm#31 0x00007c49d4c2a28b __libc_start_main ./csu/../csu/libc-start.c:347:5
llvm#32 0x000058ee97c309a5 _start (/usr/local/bin/opt+0x4f169a5)
```

This is caused by a type mismatch between
`SE.getSCEV(DerefRK.IRArgValue)` and `DerefBytesSCEV`.
Fixing this by extending them to the wider type.
Men-cotton pushed a commit that referenced this pull request Mar 21, 2026
…D tensor.extract (llvm#187085)

Vectorizing a rank-0 `linalg.generic` whose body contains
`tensor.extract` with data-dependent indices hits the Gather
classification in `getTensorExtractMemoryAccessPattern` because
`isOutput1DVector` returns false for a 0-D result. This produces an
invalid `vector.gather` where operand #2 must be a vector of index
values but gets a scalar `index` instead.

Fix classifies a 0-D result as ScalarBroadcast rather than Gather, and
skips mask generation for 0-D in that path.
Men-cotton pushed a commit that referenced this pull request Mar 27, 2026
…e edge case (llvm#188590)

llvm#186966 was reverted because
the test case triggered a use-of-uninitialized-memory
(https://lab.llvm.org/buildbot/#/builders/94/builds/16379), due to the
include directive omitting a trailing newline. This patch adds a minor
fix to avoid the use-of-uninitialized-memory, and deliberately re-adds
the test case sans trailing newline for regression testing.

MSan report prior to this fix:
```
@@@BUILD_STEP sanitizer logs: stage2/msan_track_origins check@@@
==clang-scan-deps==616960==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x5555599c3300 in isAnnotation /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/include/clang/Lex/Token.h:131:38
    #1 0x5555599c3300 in setLength /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/include/clang/Lex/Token.h:152:13
    #2 0x5555599c3300 in clang::Lexer::FormTokenWithChars(clang::Token&, char const*, clang::tok::TokenKind) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/include/clang/Lex/Lexer.h:644:12
    #3 0x5555599cf895 in clang::Lexer::LexEndOfFile(clang::Token&, char const*) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/Lexer.cpp:3166:5
    #4 0x555559bb229b in clang::Preprocessor::Lex(clang::Token&) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/Preprocessor.cpp:916:11
    llvm#5 0x555559aa5365 in __invoke<void (clang::Preprocessor::*&)(clang::Token &), clang::Preprocessor *, clang::Token &> /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/libcxx_install_msan_track_origins/include/c++/v1/__type_traits/invoke.h:90:27
    llvm#6 0x555559aa5365 in invoke<void (clang::Preprocessor::*&)(clang::Token &), clang::Preprocessor *, clang::Token &> /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/libcxx_install_msan_track_origins/include/c++/v1/__functional/invoke.h:29:10
    llvm#7 0x555559aa5365 in operator()<void (clang::Preprocessor::*)(clang::Token &)> /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/PPDirectives.cpp:470:5
    llvm#8 0x555559aa5365 in clang::Preprocessor::CheckEndOfDirective(llvm::StringRef, bool, llvm::SmallVectorImpl<clang::Token>*) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/PPDirectives.cpp:478:5
    llvm#9 0x555559ab96b5 in clang::Preprocessor::HandleIncludeDirective(clang::SourceLocation, clang::Token&, clang::detail::SearchDirIteratorImpl<true>, clang::FileEntry const*) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/PPDirectives.cpp:2205:7
    ...
```
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