llvm-project/clang/lib/CodeGen
Richard Smith a1c9d4d932 Simplify: we don't need any special-case lifetime extension when initializing
declarations of reference type; they're handled by the general case handling of
MaterializeTemporaryExpr.

llvm-svn: 183875
2013-06-12 23:38:09 +00:00
..
ABIInfo.h Standardize accesses to the TargetInfo in IR-gen. 2013-04-16 22:48:15 +00:00
BackendUtil.cpp Plumb through the -fsplit-stack option using the existing backend 2013-04-04 06:29:47 +00:00
CGAtomic.cpp Fix style bug introduced in r183033. 2013-05-31 20:12:49 +00:00
CGBlocks.cpp Comment: use \code...\endcode for code examples 2013-05-08 23:09:44 +00:00
CGBlocks.h Remove useless 'llvm::' qualifier from names like StringRef and others that are 2013-01-12 19:30:44 +00:00
CGBuilder.h Rewrite #includes for llvm/Foo.h to llvm/IR/Foo.h as appropriate to 2013-01-02 11:45:17 +00:00
CGBuiltin.cpp Fix __clear_cache on ARM. 2013-05-14 12:45:47 +00:00
CGCUDANV.cpp Use the actual ABI-determined C calling convention for runtime 2013-02-28 19:01:20 +00:00
CGCUDARuntime.cpp Sort all of Clang's files under 'lib', and fix up the broken headers 2012-12-04 09:13:33 +00:00
CGCUDARuntime.h CUDA: IR generation support for device stubs 2011-10-06 18:51:56 +00:00
CGCXX.cpp [ms-cxxabi] Thread GlobalDecls through to CodeGenModule::getFunctionLinkage. 2013-06-05 17:49:37 +00:00
CGCXXABI.cpp [ms-cxxabi] Implement member pointer conversions 2013-05-09 21:01:17 +00:00
CGCXXABI.h [ms-cxxabi] Implement MSVC virtual base adjustment 2013-05-29 18:02:47 +00:00
CGCall.cpp Simplify: we don't need any special-case lifetime extension when initializing 2013-06-12 23:38:09 +00:00
CGCall.h Under ARC, when we're passing the address of a strong variable 2013-03-23 02:35:54 +00:00
CGClass.cpp PR12086, PR15117 2013-06-12 22:31:48 +00:00
CGCleanup.cpp Reapply r183721, reverted in r183776, with a fix for a bug in the former (we 2013-06-12 20:42:33 +00:00
CGCleanup.h Reapply r183721, reverted in r183776, with a fix for a bug in the former (we 2013-06-12 20:42:33 +00:00
CGDebugInfo.cpp 80-column fixup after recent change to getOrCreateType. 2013-06-07 22:54:39 +00:00
CGDebugInfo.h PR16214: Debug Info: -flimit-debug-info doesn't omit definitions for types used via typedefs 2013-06-05 05:32:23 +00:00
CGDecl.cpp Simplify: we don't need any special-case lifetime extension when initializing 2013-06-12 23:38:09 +00:00
CGDeclCXX.cpp Simplify: we don't need any special-case lifetime extension when initializing 2013-06-12 23:38:09 +00:00
CGException.cpp Set the debug location for landing pad code to the canonical EH location. 2013-05-16 00:41:29 +00:00
CGExpr.cpp Simplify: we don't need any special-case lifetime extension when initializing 2013-06-12 23:38:09 +00:00
CGExprAgg.cpp Simplify: we don't need any special-case lifetime extension when initializing 2013-06-12 23:38:09 +00:00
CGExprCXX.cpp PR12086, PR15117 2013-06-12 22:31:48 +00:00
CGExprComplex.cpp Add support for complex compound assignments where the LHS is a scalar. 2013-06-12 01:40:06 +00:00
CGExprConstant.cpp PR12086, PR15117 2013-06-12 22:31:48 +00:00
CGExprScalar.cpp Add support for complex compound assignments where the LHS is a scalar. 2013-06-12 01:40:06 +00:00
CGObjC.cpp Correctly emit certain implicit references to 'self' even within 2013-05-03 07:33:41 +00:00
CGObjCGNU.cpp Use the actual ABI-determined C calling convention for runtime 2013-02-28 19:01:20 +00:00
CGObjCMac.cpp Use the ugly PRIx64 macro to make format string portable. 2013-04-22 16:10:38 +00:00
CGObjCRuntime.cpp Standardize accesses to the TargetInfo in IR-gen. 2013-04-16 22:48:15 +00:00
CGObjCRuntime.h Use the actual ABI-determined C calling convention for runtime 2013-02-28 19:01:20 +00:00
CGOpenCLRuntime.cpp Add OpenCL samplers as Clang builtin types and check sampler related restrictions. 2013-02-07 10:55:47 +00:00
CGOpenCLRuntime.h Rewrite #includes for llvm/Foo.h to llvm/IR/Foo.h as appropriate to 2013-01-02 11:45:17 +00:00
CGRTTI.cpp Fix linkage computation for derived types in inline functions. 2013-05-25 17:16:20 +00:00
CGRecordLayout.h Rewrite #includes for llvm/Foo.h to llvm/IR/Foo.h as appropriate to 2013-01-02 11:45:17 +00:00
CGRecordLayoutBuilder.cpp Standardize accesses to the TargetInfo in IR-gen. 2013-04-16 22:48:15 +00:00
CGStmt.cpp Simplify: we don't need any special-case lifetime extension when initializing 2013-06-12 23:38:09 +00:00
CGVTT.cpp simplify a bunch of code to use the well-known LLVM IR types computed by CodeGenModule. 2012-02-07 00:39:47 +00:00
CGVTables.cpp [ms-cxxabi] Thread GlobalDecls through to CodeGenModule::getFunctionLinkage. 2013-06-05 17:49:37 +00:00
CGVTables.h The standard ARM C++ ABI dictates that inline functions are 2013-01-25 22:31:03 +00:00
CGValue.h Initial support for struct-path aware TBAA. 2013-04-04 21:53:22 +00:00
CMakeLists.txt The IRReader header is now part of its own library. Update the include 2013-03-26 02:25:54 +00:00
CodeGenAction.cpp Adding support for MSVC #pragma detect_mismatch functionality by emitting a FAILIFMISMATCH linker command into the object file. 2013-06-04 02:07:14 +00:00
CodeGenFunction.cpp Reapply r183721, reverted in r183776, with a fix for a bug in the former (we 2013-06-12 20:42:33 +00:00
CodeGenFunction.h Simplify: we don't need any special-case lifetime extension when initializing 2013-06-12 23:38:09 +00:00
CodeGenModule.cpp PR12086, PR15117 2013-06-12 22:31:48 +00:00
CodeGenModule.h PR12086, PR15117 2013-06-12 22:31:48 +00:00
CodeGenTBAA.cpp Cleanup handling of UniqueExternalLinkage. 2013-05-13 00:12:11 +00:00
CodeGenTBAA.h Fixed comment typo. 2013-06-08 00:27:19 +00:00
CodeGenTypes.cpp Don't treat a non-deduced 'auto' type as being type-dependent. Instead, there 2013-04-30 13:56:41 +00:00
CodeGenTypes.h Standardize accesses to the TargetInfo in IR-gen. 2013-04-16 22:48:15 +00:00
ItaniumCXXABI.cpp [ms-cxxabi] Implement MSVC virtual base adjustment 2013-05-29 18:02:47 +00:00
Makefile BUILD_ARCHIVE is the default for libraries, no need to set it. 2010-07-18 00:14:47 +00:00
MicrosoftCXXABI.cpp [ms-cxxabi] Fix vbptr offsets in memptrs when the vbptr is in an nvbase 2013-06-05 15:58:29 +00:00
ModuleBuilder.cpp Adding support for MSVC #pragma detect_mismatch functionality by emitting a FAILIFMISMATCH linker command into the object file. 2013-06-04 02:07:14 +00:00
README.txt
TargetInfo.cpp Silencing a signed vs unsigned comparison mismatch in MSVC. 2013-06-12 15:03:45 +00:00
TargetInfo.h Diagnose malformed x86 inline asm using 'y' constraint. 2013-06-07 00:04:50 +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!

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