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This PR removes the use of an unnecessary MOVSP in the function epilogue (#19 ). Restoring the frame pointer when using Xtensa Windowed Regisers option is not needed because original stack pointer will get restored when returning (goes to register window of caller which contains original stack pointer).

For reference:
test.c:

int secretpin() {
    return 1337;
}

Compiling with xtensa-esp32-elf-gcc -c test.c:

00000000 <secretpin>:
   0:	004136        	entry	a1, 32
   3:	017d      	mov.n	a7, a1
   5:	39a522        	movi	a2, 0x539
   8:	f01d      	retw.n

Compiling with $LLVM_INSTALL_DIR/bin/clang --target="xtensa-freestanding" -mcpu=esp32 -c test.c:

00000000 <secretpin>:
   0:	004136        	entry	a1, 32
   3:	017d      	mov.n	a7, a1
   5:	39a522        	movi	a2, 0x539
   8:	001710        	movsp	a1, a7
   b:	f01d      	retw.n

@github-actions github-actions bot changed the title [Xtensa] Remove unnecessary MOVSP in epilogue. [Xtensa] Remove unnecessary MOVSP in epilogue. (LLVM-83) Jan 26, 2021
espressif-bot pushed a commit that referenced this pull request Jan 4, 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
    #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
    #6 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    #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
    #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
    #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
    #10 0x55c20da34986 in clang::interp::Compiler<clang::interp::EvalEmitter>::VisitDeclRefExpr(clang::DeclRefExpr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:7192:16
    #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
    #12 0x55c20da65d3f in clang::interp::Compiler<clang::interp::EvalEmitter>::visit(clang::Expr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4293:16
    #13 0x55c20da57348 in clang::interp::Compiler<clang::interp::EvalEmitter>::VisitCXXTypeidExpr(clang::CXXTypeidExpr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:3893:14
    #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
    #15 0x55c20da65d3f in clang::interp::Compiler<clang::interp::EvalEmitter>::visit(clang::Expr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4293:16
    #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
    #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
    #18 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    #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
    #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
    #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
    #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
    #23 0x55c20b9154da in clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) llvm-project/clang/lib/Sema/SemaDecl.cpp:14941:27
    #24 0x55c20b910f36 in clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) llvm-project/clang/lib/Sema/SemaDecl.cpp:14280:3
    #25 0x55c20ad044ee in clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2639:17
    #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
    #27 0x55c20abd8a43 in clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1181:10
    #28 0x55c20abd7654 in clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1203:12
    #29 0x55c20abd4d9c in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp:1031:14
    #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
    #31 0x55c20ac950c7 in clang::Parser::ParseNamespace(clang::DeclaratorContext, clang::SourceLocation&, clang::SourceLocation) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:218:3
    #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
    #33 0x55c20abd3f88 in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp
    #34 0x55c20abcfe33 in clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) llvm-project/clang/lib/Parse/Parser.cpp:744:12
    #35 0x55c20abb214e in clang::ParseAST(clang::Sema&, bool, bool) llvm-project/clang/lib/Parse/ParseAST.cpp:170:20
    #36 0x55c20a90adaa in clang::ASTFrontendAction::ExecuteAction() llvm-project/clang/lib/Frontend/FrontendAction.cpp:1432:3
    #37 0x55c20a9095bf in clang::FrontendAction::Execute() llvm-project/clang/lib/Frontend/FrontendAction.cpp:1312:3
    #38 0x55c20a76cdc7 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) llvm-project/clang/lib/Frontend/CompilerInstance.cpp:1004:33
    #39 0x55c20805aab0 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:310:25
    #40 0x55c20802e823 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) llvm-project/clang/tools/driver/cc1_main.cpp:304:15
    #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
    #42 0x55c20801ea91 in clang_main(int, char**, llvm::ToolContext const&) llvm-project/clang/tools/driver/driver.cpp:268:12
    #43 0x55c20801a6af in main blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/clang-driver.cpp:17:10
    #44 0x7f79c4214351 in __libc_start_main (/usr/libc/lib64/libc.so.6+0x61351) (BuildId: ca23ec6d935352118622ce674a8bb52d)
    #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
    #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
    #6 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    #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
    #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
    #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
    #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
    #11 0x55c20b9154da in clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) llvm-project/clang/lib/Sema/SemaDecl.cpp:14941:27
    #12 0x55c20b910f36 in clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) llvm-project/clang/lib/Sema/SemaDecl.cpp:14280:3
    #13 0x55c20ad044ee in clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2639:17
    #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
    #15 0x55c20abd8a43 in clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1181:10
    #16 0x55c20abd7654 in clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1203:12
    #17 0x55c20abd4d9c in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp:1031:14
    #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
    #19 0x55c20ac950c7 in clang::Parser::ParseNamespace(clang::DeclaratorContext, clang::SourceLocation&, clang::SourceLocation) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:218:3
    #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
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