llvm-project/clang/lib/CodeGen
Tim Northover 5a1558ec31 ARM ABI: simplify decisions on whether args can be expanded.
Homogeneous aggregates on AAPCS_VFP ARM need to be passed *without* being
flattened (e.g. [2 x float] rather than "float, float") for various weird ABI
reasons. However, this isn't the case for anything else; further, we know at
the ABIArgInfo::getDirect callsites whether this flattening is allowed.

So, we can get more unified ARM code, with a simpler Clang, by just using that
knowledge directly.

llvm-svn: 221559
2014-11-07 22:30:50 +00:00
..
ABIInfo.h Fix ARM HVA classification of classes with non-virtual bases 2014-10-31 17:10:41 +00:00
BackendUtil.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CGAtomic.cpp CodeGen: Don't completely mess-up optimized atomic libcalls 2014-08-29 07:27:49 +00:00
CGBlocks.cpp Fix a crash when compiling blocks in OpenCL with multiple 2014-08-14 09:37:50 +00:00
CGBlocks.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CGBuilder.h typo 2014-09-10 16:59:01 +00:00
CGBuiltin.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CGCUDANV.cpp [C++11] Add 'override' keyword to virtual methods that override their base class. 2014-03-12 06:41:41 +00:00
CGCUDARuntime.cpp Pass expressions instead of argument ranges to EmitCall/EmitCXXConstructorCall. 2014-08-21 20:26:47 +00:00
CGCUDARuntime.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CGCXX.cpp ignore -mconstructor-aliases when adding field paddings for asan 2014-10-31 19:01:02 +00:00
CGCXXABI.cpp MS ABI: Implement thread_local for global variables 2014-10-05 05:05:40 +00:00
CGCXXABI.h CodeGen: Declutter the emitVirtualObjectDelete interface 2014-11-01 07:37:17 +00:00
CGCall.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CGCall.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CGClass.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CGCleanup.cpp Revert r218865 because it introduced PR21236, a crash in codegen emitting the try block. 2014-10-10 04:05:00 +00:00
CGCleanup.h Replace a destructor of EHCleanupScope with a Destroy() method to reflect the current usage. 2014-10-08 18:31:54 +00:00
CGDebugInfo.cpp Return a DIDescriptor from CGDebugInfo::getDeclarationOrDefinition... 2014-11-06 21:12:06 +00:00
CGDebugInfo.h Return a DIDescriptor from CGDebugInfo::getDeclarationOrDefinition... 2014-11-06 21:12:06 +00:00
CGDecl.cpp Emit OpenCL local global variables without zeorinitializer 2014-11-03 16:51:53 +00:00
CGDeclCXX.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CGException.cpp CodeGen: Strip qualifiers from qualified array types in catches 2014-10-12 06:58:22 +00:00
CGExpr.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CGExprAgg.cpp PR18097: Support initializing an _Atomic(T) from an object of C++ class type T 2014-07-31 06:31:19 +00:00
CGExprCXX.cpp CodeGen: Declutter the emitVirtualObjectDelete interface 2014-11-01 07:37:17 +00:00
CGExprComplex.cpp Remove CastKind typedef from CastExpr since CastKind is in the clang namespace. 2014-10-31 06:57:10 +00:00
CGExprConstant.cpp CodeGen: ConstStructBuilder must verify packed constraints after padding 2014-10-19 23:40:06 +00:00
CGExprScalar.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CGLoopInfo.cpp Rename metadata llvm.loop.vectorize.unroll to llvm.loop.vectorize.interleave. 2014-07-21 23:10:56 +00:00
CGLoopInfo.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CGObjC.cpp Objective-C. revert patch for rdar://17554063. 2014-10-28 18:28:16 +00:00
CGObjCGNU.cpp Use the new LLVM_END_WITH_NULL name 2014-11-04 01:13:43 +00:00
CGObjCMac.cpp Don't manually insert L prefixes. 2014-11-06 13:30:38 +00:00
CGObjCRuntime.cpp Update for llvm api change. 2014-06-04 18:51:46 +00:00
CGObjCRuntime.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CGOpenCLRuntime.cpp [C++11] Use 'nullptr'. CodeGen edition. 2014-05-21 05:09:00 +00:00
CGOpenCLRuntime.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CGOpenMPRuntime.cpp Fix unicode chars into ascii in comment lines. 2014-10-27 08:08:18 +00:00
CGOpenMPRuntime.h [OPENMP] Codegen for 'num_threads' clause in 'parallel' directive. 2014-10-13 08:23:51 +00:00
CGRecordLayout.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CGRecordLayoutBuilder.cpp CodeGen: Cleanup CGRecordLowering::lowerUnion a little 2014-10-15 16:36:11 +00:00
CGStmt.cpp Improved capturing variable-length array types in CapturedStmt. 2014-10-29 12:21:55 +00:00
CGStmtOpenMP.cpp [OPENMP] Codegen for 'private' clause in 'parallel' directive. 2014-10-21 03:16:40 +00:00
CGVTT.cpp Remove the -fhidden-weak-vtables -cc1 option. It was dead, 2014-02-08 00:41:16 +00:00
CGVTables.cpp CodeGen: Virtual dtor thunks shouldn't have this marked as 'returned' 2014-11-01 05:42:23 +00:00
CGVTables.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CGValue.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CMakeLists.txt cmake: Conditionalize CodeGen's dependency on intrinsics_gen 2014-11-05 20:30:55 +00:00
CodeGenABITypes.cpp Add coverage mapping generation. 2014-08-04 18:41:51 +00:00
CodeGenAction.cpp Update for LLVM API change. 2014-10-28 00:29:51 +00:00
CodeGenFunction.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CodeGenFunction.h Silence a warning from MSVC "14" by making an enum unsigned 2014-10-31 23:33:56 +00:00
CodeGenModule.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
CodeGenModule.h CodeGen: Virtual dtor thunks shouldn't have this marked as 'returned' 2014-11-01 05:42:23 +00:00
CodeGenPGO.cpp Reapply "InstrProf: Update for the LLVM API change in r218879" 2014-10-02 16:44:01 +00:00
CodeGenPGO.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CodeGenTBAA.cpp [C++11] Use 'nullptr'. CodeGen edition. 2014-05-21 05:09:00 +00:00
CodeGenTBAA.h Header guard canonicalization, clang part. 2014-08-13 16:25:19 +00:00
CodeGenTypes.cpp MS ABI: Don't ICE for pointers to pointers to members of incomplete classes 2014-09-18 22:05:54 +00:00
CodeGenTypes.h Use ClangToLLVMArgsMapping in CodeGenTypes::GetFunctionType(). NFC. 2014-09-29 22:08:00 +00:00
CoverageMappingGen.cpp Reapply "InstrProf: Update for the LLVM API change in r218879" 2014-10-02 16:44:01 +00:00
CoverageMappingGen.h Reapply "InstrProf: Update for the LLVM API change in r218879" 2014-10-02 16:44:01 +00:00
EHScopeStack.h Silence a warning from MSVC "14" by making an enum unsigned 2014-10-31 23:33:56 +00:00
ItaniumCXXABI.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
Makefile
MicrosoftCXXABI.cpp CodeGen: Declutter the emitVirtualObjectDelete interface 2014-11-01 07:37:17 +00:00
ModuleBuilder.cpp [modules] Fix a rejects-valid resulting from emitting an inline function 2014-08-13 21:15:09 +00:00
README.txt
SanitizerMetadata.cpp Introduce a SanitizerKind enum to LangOptions. 2014-11-07 22:29:38 +00:00
SanitizerMetadata.h [ASan] Improve blacklisting of global variables. 2014-10-17 22:37:33 +00:00
TargetInfo.cpp ARM ABI: simplify decisions on whether args can be expanded. 2014-11-07 22:30:50 +00:00
TargetInfo.h [OPENMP] Codegen of the ‘aligned’ clause for the ‘omp simd’ directive. 2014-09-30 05:29:28 +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!

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