llvm-project/clang/lib/CodeGen
Douglas Gregor a71cc15361 Implement promotion for enumeration types.
WHAT!?!

It turns out that Type::isPromotableIntegerType() was not considering
enumeration types to be promotable, so we would never do the
promotion despite having properly computed the promotion type when the
enum was defined. Various operations on values of enum type just
"worked" because we could still compute the integer rank of an enum
type; the oddity, however, is that operations such as "add an enum and
an unsigned" would often have an enum result type (!). The bug
actually showed up as a spurious -Wformat diagnostic
(<rdar://problem/7595366>), but in theory it could cause miscompiles.

In this commit:
  - Enum types with a promotion type of "int" or "unsigned int" are
  promotable.
  - Tweaked the computation of promotable types for enums
  - For all of the ABIs, treat enum types the same way as their
  underlying types (*not* their promotion types) for argument passing
  and return values
  - Extend the ABI tester with support for enumeration types

llvm-svn: 95117
2010-02-02 20:10:50 +00:00
..
ABIInfo.h x86-64 ABI: If a type is a C++ record with either a non-trivial destructor or a non-trivial copy constructor, it should be passed in a pointer. Daniel, plz review. 2009-09-16 15:53:40 +00:00
CGBlocks.cpp Change the return type of ASTContext::getDeclAlignInBytes() to CharUnits and, 2010-01-27 17:10:57 +00:00
CGBlocks.h Use CharUnits for alignments in character units. 2010-01-26 19:13:33 +00:00
CGBuilder.h Disable generation of basic block names in NDEBUG mode. 2008-11-12 00:01:12 +00:00
CGBuiltin.cpp Add bzero builtin; this should help codegen quality for code using this 2010-01-23 19:00:10 +00:00
CGCXX.cpp Move a few more functions away from CGCXX and to CGClass and CGExprCXX. 2010-01-01 20:29:01 +00:00
CGCXX.h Remove tabs, and whitespace cleanups. 2009-09-09 15:08:12 +00:00
CGCall.cpp Start creating CXXBindReferenceExpr nodes when binding complex types to references. 2010-01-31 18:34:51 +00:00
CGCall.h Fill in the return value slot in CGExprAgg::VisitCallExpr. This takes us halfway towards fixing PR5824. 2009-12-24 20:40:36 +00:00
CGClass.cpp Set the correct vtable pointers _before_ generating code for any member initializers. Fixes about ~2000 clang/LLVM tests in the clang-on-clang build. 2010-02-02 19:58:43 +00:00
CGDebugInfo.cpp Fix FIXME and surrounding comment. 2010-02-01 22:51:29 +00:00
CGDebugInfo.h Emit debug info for namespaces. 2010-02-01 19:16:32 +00:00
CGDecl.cpp Start creating CXXBindReferenceExpr nodes when binding complex types to references. 2010-01-31 18:34:51 +00:00
CGDeclCXX.cpp global variable that binds reference to a non-lvalue reproted 2010-01-25 21:40:39 +00:00
CGException.cpp Fix last patch, catch of reference to non-pointer. 2010-01-01 03:20:32 +00:00
CGExpr.cpp Move pointer to data member emission to CodeGenModule and use it in CGExprConstant. Fixes PR5674. 2010-02-02 03:37:46 +00:00
CGExprAgg.cpp Some class related cleanup. 2010-01-31 01:36:53 +00:00
CGExprCXX.cpp Check in a test case and a nasty workaround for PR6199. 2010-02-02 07:10:35 +00:00
CGExprComplex.cpp refactor pre/postinc logic into CGF and require the caller to pass in the 2010-01-09 21:40:03 +00:00
CGExprConstant.cpp Use the Arg variable rather than re-computing it. This also silences GCC's 2010-02-02 12:15:55 +00:00
CGExprScalar.cpp Move pointer to data member emission to CodeGenModule and use it in CGExprConstant. Fixes PR5674. 2010-02-02 03:37:46 +00:00
CGObjC.cpp Created __builtin___NSStringMakeConstantString() builtin, which generates constant Objective-C strings. 2010-01-23 02:40:42 +00:00
CGObjCGNU.cpp Unique ObjC strings (GNU Runtime); fix for PR6142. Note: Doing this in the runtime-specific code is a bit ugly. It would be a good idea to hoist all of the string / protocol uniqueing code up into CGObjCRuntime or CodeGenModule and only handle emitting the original versions in the runtime-specific code. 2010-01-27 12:49:23 +00:00
CGObjCMac.cpp NeXT: Add support for -fobjc-legacy-dispatch. 2010-02-01 21:07:33 +00:00
CGObjCRuntime.h Created __builtin___NSStringMakeConstantString() builtin, which generates constant Objective-C strings. 2010-01-23 02:40:42 +00:00
CGRTTI.cpp Fix linkage for RTTI names by re-using the logic for computing the 2010-01-06 22:00:56 +00:00
CGRecordLayoutBuilder.cpp Improve handling of emitting 'null' pointers to data members. 2010-02-02 05:17:25 +00:00
CGRecordLayoutBuilder.h Improve handling of emitting 'null' pointers to data members. 2010-02-02 05:17:25 +00:00
CGStmt.cpp More asm cleanup. 2010-01-30 20:05:21 +00:00
CGTemporaries.cpp Fix double-destruction assertion to account for temporaries in conditionals 2009-12-24 18:16:21 +00:00
CGVTT.cpp Move the VTT related code into its own file, CGVTT.cpp 2010-01-21 16:50:45 +00:00
CGValue.h Fix documentation. 2009-11-03 16:11:57 +00:00
CGVtable.cpp Move pointer to data member emission to CodeGenModule and use it in CGExprConstant. Fixes PR5674. 2010-02-02 03:37:46 +00:00
CGVtable.h Store the address points for constructor vtables directly in the VTT builder, because that's the only time they're needed. 2010-01-14 02:29:07 +00:00
CMakeLists.txt Move the VTT related code into its own file, CGVTT.cpp 2010-01-21 16:50:45 +00:00
CodeGenFunction.cpp Fix a nasty bug where temporaries weren't marked as being conditional in some cases. 2010-01-24 00:20:05 +00:00
CodeGenFunction.h Move pointer to data member emission to CodeGenModule and use it in CGExprConstant. Fixes PR5674. 2010-02-02 03:37:46 +00:00
CodeGenModule.cpp Don't explicitly force utf strings into the __TEXT,__ustring 2010-02-01 20:59:08 +00:00
CodeGenModule.h Move pointer to data member emission to CodeGenModule and use it in CGExprConstant. Fixes PR5674. 2010-02-02 03:37:46 +00:00
CodeGenTypes.cpp Use the new isInteger() method in a couple places, some random cleanup, and 2010-01-11 19:58:10 +00:00
CodeGenTypes.h Improve handling of emitting 'null' pointers to data members. 2010-02-02 05:17:25 +00:00
GlobalDecl.h update to match LLVM API change: 2009-12-15 07:26:51 +00:00
Makefile -fno-rtti is now the default. 2010-01-24 20:43:31 +00:00
Mangle.cpp Name mangling for cast expressions, from Matthias Schiffer! Fixes PR5876. 2010-01-29 16:37:09 +00:00
Mangle.h Work-in-progress: teach mangler how to mangle thunks for destructors. 2009-12-03 00:03:05 +00:00
ModuleBuilder.cpp Remove ';' after method definition. Noticed by clang++, which one would think 2009-12-19 17:50:07 +00:00
README.txt These IRgen improvements have been done. 2009-07-23 03:03:07 +00:00
TargetInfo.cpp Implement promotion for enumeration types. 2010-02-02 20:10:50 +00:00
TargetInfo.h Eliminate some Clang warnings 2010-01-22 15:41:14 +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!

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