llvm-project/clang/lib/CodeGen
Sean Fertile d900dd0c23 Revert "[CodeGenCXX] Treat 'this' as noalias in constructors"
This reverts commit https://reviews.llvm.org/rL344150 which causes
MachineOutliner related failures on the ppc64le multistage buildbot.

llvm-svn: 344526
2018-10-15 15:43:00 +00:00
..
ABIInfo.h Delete BuiltinCC. NFC. 2018-03-20 22:02:57 +00:00
Address.h
BackendUtil.cpp Add a flag to remap manglings when reading profile data information. 2018-10-10 23:13:35 +00:00
CGAtomic.cpp Do not use optimized atomic libcalls for misaligned atomics. 2018-09-07 23:57:54 +00:00
CGBlocks.cpp Revert r326937 "[OpenCL] Remove block invoke function from emitted block literal struct" 2018-10-02 13:02:24 +00:00
CGBlocks.h Fix the type of 1<<31 integer constants. 2018-09-24 17:51:15 +00:00
CGBuilder.h Remove trailing space 2018-07-30 19:24:48 +00:00
CGBuiltin.cpp [WebAssembly] Saturating float-to-int builtins 2018-10-11 00:07:55 +00:00
CGCUDANV.cpp [CUDA] Use all 64 bits of GUID in __nv_module_id 2018-10-05 18:39:58 +00:00
CGCUDARuntime.cpp Refactor call emission to package the function pointer together with 2016-10-26 23:46:34 +00:00
CGCUDARuntime.h
CGCXX.cpp Remove trailing space 2018-07-30 19:24:48 +00:00
CGCXXABI.cpp Remove trailing space 2018-07-30 19:24:48 +00:00
CGCXXABI.h [WebAssembly] Use Windows EH instructions for Wasm EH 2018-05-31 22:18:13 +00:00
CGCall.cpp Revert "[CodeGenCXX] Treat 'this' as noalias in constructors" 2018-10-15 15:43:00 +00:00
CGCall.h Remove trailing space 2018-07-30 19:24:48 +00:00
CGClass.cpp Distinguish `__block` variables that are captured by escaping blocks 2018-10-01 21:51:28 +00:00
CGCleanup.cpp [TI removal] Make `getTerminator()` return a generic `Instruction`. 2018-10-15 10:42:50 +00:00
CGCleanup.h Remove trailing space 2018-07-30 19:24:48 +00:00
CGCoroutine.cpp Port getLocStart -> getBeginLoc 2018-08-09 21:08:08 +00:00
CGDebugInfo.cpp [DebugInfo] Add support for DWARF5 call site-related attributes 2018-10-05 20:37:17 +00:00
CGDebugInfo.h [DebugInfo] Add support for DWARF5 call site-related attributes 2018-10-05 20:37:17 +00:00
CGDecl.cpp Distinguish `__block` variables that are captured by escaping blocks 2018-10-01 21:51:28 +00:00
CGDeclCXX.cpp [AArch64] Enable return address signing for static ctors 2018-09-13 10:25:36 +00:00
CGException.cpp [TI removal] Make `getTerminator()` return a generic `Instruction`. 2018-10-15 10:42:50 +00:00
CGExpr.cpp Distinguish `__block` variables that are captured by escaping blocks 2018-10-01 21:51:28 +00:00
CGExprAgg.cpp Remove trailing space 2018-07-30 19:24:48 +00:00
CGExprCXX.cpp Port getLocStart -> getBeginLoc 2018-08-09 21:08:08 +00:00
CGExprComplex.cpp Remove \brief commands from doxygen comments. 2018-05-09 01:00:01 +00:00
CGExprConstant.cpp [CodeGen] IncompleteArray Support 2018-08-08 00:01:21 +00:00
CGExprScalar.cpp [clang][ubsan] Split Implicit Integer Truncation Sanitizer into unsigned and signed checks 2018-10-11 09:09:50 +00:00
CGGPUBuiltin.cpp Recommit r326946 after reducing CallArgList memory footprint 2018-03-15 15:25:19 +00:00
CGLoopInfo.cpp [CodeGen] Emit parallel_loop_access for each loop in the loop stack. 2018-08-03 04:42:52 +00:00
CGLoopInfo.h [UnrollAndJam] Add unroll_and_jam pragma handling 2018-08-01 14:36:12 +00:00
CGNonTrivialStruct.cpp [CodeGen] Before entering the loop that copies a non-trivial array field 2018-10-02 01:00:44 +00:00
CGObjC.cpp Port getLocEnd -> getEndLoc 2018-08-09 21:09:38 +00:00
CGObjCGNU.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-26 22:16:28 +00:00
CGObjCMac.cpp [CodeGen] Handle extern references to OBJC_CLASS_$_* 2018-10-12 17:22:10 +00:00
CGObjCRuntime.cpp Fix a deprecated warning in the last commit. 2018-08-10 12:53:18 +00:00
CGObjCRuntime.h [CodeGen] Merge identical block descriptor global variables. 2018-08-17 15:46:07 +00:00
CGOpenCLRuntime.cpp Revert r326937 "[OpenCL] Remove block invoke function from emitted block literal struct" 2018-10-02 13:02:24 +00:00
CGOpenCLRuntime.h Revert r326937 "[OpenCL] Remove block invoke function from emitted block literal struct" 2018-10-02 13:02:24 +00:00
CGOpenMPRuntime.cpp [OPENMP] Fix emission of the __kmpc_global_thread_num. 2018-10-05 15:08:53 +00:00
CGOpenMPRuntime.h [OPENMP] Fix emission of the __kmpc_global_thread_num. 2018-10-05 15:08:53 +00:00
CGOpenMPRuntimeNVPTX.cpp [OPENMP][NVPTX]Reduce memory usage in target region. 2018-10-12 20:19:59 +00:00
CGOpenMPRuntimeNVPTX.h [OPENMP][NVPTX]Reduce memory usage in target region. 2018-10-12 20:19:59 +00:00
CGRecordLayout.h Remove \brief commands from doxygen comments. 2018-05-09 01:00:01 +00:00
CGRecordLayoutBuilder.cpp Remove trailing space 2018-07-30 19:24:48 +00:00
CGStmt.cpp [cxx2a] P0614R1: Support init-statements in range-based for loops. 2018-09-28 18:44:09 +00:00
CGStmtOpenMP.cpp Add support for 'dynamic_allocators' clause on 'requires' directive. Differential Revision: https://reviews.llvm.org/D53079 2018-10-11 14:41:10 +00:00
CGVTT.cpp [CodeGen] Align rtti and vtable data 2018-09-12 14:09:06 +00:00
CGVTables.cpp llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...) 2018-09-26 22:16:28 +00:00
CGVTables.h Remove trailing space 2018-07-30 19:24:48 +00:00
CGValue.h Remove trailing space 2018-07-30 19:24:48 +00:00
CMakeLists.txt Compile CodeGenModule.cpp with /bigobj. 2018-06-26 17:45:26 +00:00
CodeGenABITypes.cpp Include getting generated struct offsets in CodegenABITypes 2017-10-10 23:54:21 +00:00
CodeGenAction.cpp [CodeGen][Timers] Enable llvm::TimePassesIsEnabled when -ftime-report is specified 2018-08-08 19:14:23 +00:00
CodeGenFunction.cpp [CodeGen] Revert commit https://reviews.llvm.org/rL342717 2018-09-24 18:24:18 +00:00
CodeGenFunction.h Distinguish `__block` variables that are captured by escaping blocks 2018-10-01 21:51:28 +00:00
CodeGenModule.cpp Add a flag to remap manglings when reading profile data information. 2018-10-10 23:13:35 +00:00
CodeGenModule.h [OPENMP] Add support for OMP5 requires directive + unified_address clause 2018-09-26 04:28:39 +00:00
CodeGenPGO.cpp [cxx2a] P0614R1: Support init-statements in range-based for loops. 2018-09-28 18:44:09 +00:00
CodeGenPGO.h Remove a dead field. NFC. 2017-04-24 20:54:36 +00:00
CodeGenTBAA.cpp [CodeGen] Fix generation of TBAA tags for may-alias accesses 2018-02-20 12:33:04 +00:00
CodeGenTBAA.h [CodeGen] Fix generation of TBAA tags for may-alias accesses 2018-02-20 12:33:04 +00:00
CodeGenTypeCache.h Delete BuiltinCC. NFC. 2018-03-20 22:02:57 +00:00
CodeGenTypes.cpp Remove trailing space 2018-07-30 19:24:48 +00:00
CodeGenTypes.h Remove trailing space 2018-07-30 19:24:48 +00:00
ConstantEmitter.h [NFC] typo 2018-07-11 19:51:40 +00:00
ConstantInitBuilder.cpp Remove trailing space 2018-07-30 19:24:48 +00:00
CoverageMappingGen.cpp [cxx2a] P0614R1: Support init-statements in range-based for loops. 2018-09-28 18:44:09 +00:00
CoverageMappingGen.h Remove \brief commands from doxygen comments. 2018-05-09 01:00:01 +00:00
EHScopeStack.h Spelling mistakes in comments. NFCI. (PR27635) 2017-03-30 14:13:19 +00:00
ItaniumCXXABI.cpp [CodeGen] Align rtti and vtable data 2018-09-12 14:09:06 +00:00
MacroPPCallbacks.cpp Reland '[clang] Adding CharacteristicKind to PPCallbacks::InclusionDirective' 2018-05-10 19:05:36 +00:00
MacroPPCallbacks.h Add header guards to some headers that are missing them 2018-09-03 16:26:36 +00:00
MicrosoftCXXABI.cpp [CodeGen] Align rtti and vtable data 2018-09-12 14:09:06 +00:00
ModuleBuilder.cpp [MS] Defer dllexport inline friend functions like other inline methods 2018-09-18 23:16:30 +00:00
ObjectFilePCHContainerOperations.cpp [clang] Update uses of DEBUG macro to LLVM_DEBUG. 2018-05-15 13:30:56 +00:00
README.txt
SanitizerMetadata.cpp hwasan: add -fsanitize=kernel-hwaddress flag 2018-04-13 18:05:21 +00:00
SanitizerMetadata.h
SwiftCallingConv.cpp Remove trailing space 2018-07-30 19:24:48 +00:00
TargetInfo.cpp [MinGW] Fix passing a sanitizer lib name as dependent lib 2018-10-10 09:01:00 +00:00
TargetInfo.h [CUDA][HIP] Set kernel calling convention before arrange function 2018-06-12 00:16:33 +00:00
VarBypassDetector.cpp Fix typos in clang 2018-04-06 15:14:32 +00:00
VarBypassDetector.h [CodeGen] Don't emit lifetime intrinsics for some local variables 2016-10-26 05:42:30 +00:00

README.txt

IRgen optimization opportunities.

//===---------------------------------------------------------------------===//

The common pattern of
--
short x; // or char, etc
(x == 10)
--
generates an zext/sext of x which can easily be avoided.

//===---------------------------------------------------------------------===//

Bitfields accesses can be shifted to simplify masking and sign
extension. For example, if the bitfield width is 8 and it is
appropriately aligned then is is a lot shorter to just load the char
directly.

//===---------------------------------------------------------------------===//

It may be worth avoiding creation of alloca's for formal arguments
for the common situation where the argument is never written to or has
its address taken. The idea would be to begin generating code by using
the argument directly and if its address is taken or it is stored to
then generate the alloca and patch up the existing code.

In theory, the same optimization could be a win for block local
variables as long as the declaration dominates all statements in the
block.

NOTE: The main case we care about this for is for -O0 -g compile time
performance, and in that scenario we will need to emit the alloca
anyway currently to emit proper debug info. So this is blocked by
being able to emit debug information which refers to an LLVM
temporary, not an alloca.

//===---------------------------------------------------------------------===//

We should try and avoid generating basic blocks which only contain
jumps. At -O0, this penalizes us all the way from IRgen (malloc &
instruction overhead), all the way down through code generation and
assembly time.

On 176.gcc:expr.ll, it looks like over 12% of basic blocks are just
direct branches!

//===---------------------------------------------------------------------===//