llvm-project/clang/lib/CodeGen
Douglas Gregor 9b71f0cfac Implement proper support for generating code for compound literals in
C++, which means:
  - binding the temporary as needed in Sema, so that we generate the
  appropriate call to the destructor, and
  - emitting the compound literal into the appropriate location for
  the aggregate, rather than trying to emit it as a temporary and
  memcpy() it.

Fixes PR10138 / <rdar://problem/9615901>.

llvm-svn: 133235
2011-06-17 04:59:12 +00:00
..
ABIInfo.h Fix Whitespace. 2010-10-19 06:39:39 +00:00
BackendUtil.cpp Update for llvm api change. 2011-05-25 03:44:55 +00:00
CGBlocks.cpp Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CGBlocks.h Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGBuilder.h Make CGBuilderTy a typedef again; its functionality has been rolled back 2010-07-06 18:43:48 +00:00
CGBuiltin.cpp Update the prefetch intrinsic usage. Now the last argument tells codegen 2011-06-14 05:00:30 +00:00
CGCXX.cpp Revert r131434, my commit disabling the complete-object constructor 2011-05-17 21:05:49 +00:00
CGCXXABI.cpp After some discussion with Doug, we decided that it made a lot more sense 2011-04-12 00:42:48 +00:00
CGCXXABI.h After some discussion with Doug, we decided that it made a lot more sense 2011-04-12 00:42:48 +00:00
CGCall.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGCall.h Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGClass.cpp Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CGCleanup.cpp implement rdar://9289524 - case followed immediately by break results in empty IR block, 2011-04-17 00:54:30 +00:00
CGCleanup.h Move all the cleanups framework code into a single file. 2011-01-28 11:13:47 +00:00
CGDebugInfo.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGDebugInfo.h Move GlobalDecl to AST 2011-06-14 04:02:39 +00:00
CGDecl.cpp Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CGDeclCXX.cpp Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CGException.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGException.h Fix Objective-C++ exceptions (GNU runtime). 2011-03-20 21:35:39 +00:00
CGExpr.cpp Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CGExprAgg.cpp Implement proper support for generating code for compound literals in 2011-06-17 04:59:12 +00:00
CGExprCXX.cpp Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CGExprComplex.cpp C1X: implement generic selections 2011-04-15 00:35:48 +00:00
CGExprConstant.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGExprScalar.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGObjC.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGObjCGNU.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGObjCMac.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGObjCRuntime.cpp Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CGObjCRuntime.h Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CGRTTI.cpp Make yet another placeholder type, this one marking that an expression is a bound 2011-04-26 20:42:42 +00:00
CGRecordLayout.h Convert AccessInfo::AccessAlignment to CharUnits. No change in functionality 2011-04-24 10:13:17 +00:00
CGRecordLayoutBuilder.cpp Introduce Type::isSignedIntegerOrEnumerationType() and 2011-05-20 16:38:50 +00:00
CGStmt.cpp Check the specific target to figure out if a constraint is a valid 2011-06-17 01:53:34 +00:00
CGTemporaries.cpp Fix some obvious bugs in the conditional-cleanup code and then make the 2011-01-26 19:15:39 +00:00
CGVTT.cpp Fix another regression from the "skip vtable pointer initialization" 2011-05-16 04:08:36 +00:00
CGVTables.cpp Fix another regression from the "skip vtable pointer initialization" 2011-05-16 04:08:36 +00:00
CGVTables.h Move GlobalDecl to AST 2011-06-14 04:02:39 +00:00
CGValue.h Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CMakeLists.txt Wire up the -ftest-coverage and -fprofile-arcs flags to .gcno file emission (at 2011-04-21 23:44:07 +00:00
CodeGenAction.cpp fix a bunch of comment typos found by codespell. Patch by 2011-04-15 05:22:18 +00:00
CodeGenFunction.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CodeGenFunction.h Restore correct use of GC barriers. 2011-06-16 04:16:24 +00:00
CodeGenModule.cpp Move computation of __private_extern__ visibilty to 2011-06-16 20:14:50 +00:00
CodeGenModule.h Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
CodeGenTBAA.cpp PR9214: Convert Metadata API to use ArrayRef. 2011-04-21 19:59:12 +00:00
CodeGenTBAA.h Move name mangling support from CodeGen to AST. In the 2011-01-13 18:57:25 +00:00
CodeGenTypes.cpp Make yet another placeholder type, this one marking that an expression is a bound 2011-04-26 20:42:42 +00:00
CodeGenTypes.h Move GlobalDecl to AST 2011-06-14 04:02:39 +00:00
ItaniumCXXABI.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +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 fix a bunch of comment typos found by codespell. Patch by 2011-04-15 05:22:18 +00:00
ModuleBuilder.cpp Modify some deleted function methods to better reflect reality: 2011-05-06 20:44:56 +00:00
README.txt These IRgen improvements have been done. 2009-07-23 03:03:07 +00:00
TargetInfo.cpp Automatic Reference Counting. 2011-06-15 23:02:42 +00:00
TargetInfo.h Automatic Reference Counting. 2011-06-15 23:02:42 +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!

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