Teach 2addr pass to be do more commuting. If both uses of a two-address instruction are killed, but the first operand has a use before and after the def, commute if the second operand does not suffer from the same issue.
%reg1028<def> = EXTRACT_SUBREG %reg1027<kill>, 1                                                                                                                                     
%reg1029<def> = MOV8rr %reg1028                                                                                                                                                      
%reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>                                                                                                                            
insert => %reg1030<def> = MOV8rr %reg1028                                                                                                                                            
%reg1030<def> = ADD8rr %reg1028<kill>, %reg1029<kill>, %EFLAGS<imp-def,dead>                                                                                                         

In this case, it might not be possible to coalesce the second MOV8rr                                                                                                                 
instruction if the first one is coalesced. So it would be profitable to                                                                                                              
commute it:                                                                                                                                                                          
%reg1028<def> = EXTRACT_SUBREG %reg1027<kill>, 1                                                                                                                                     
%reg1029<def> = MOV8rr %reg1028                                                                                                                                                      
%reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>                                                                                                                            
insert => %reg1030<def> = MOV8rr %reg1029                                                                                                                                            
%reg1030<def> = ADD8rr %reg1029<kill>, %reg1028<kill>, %EFLAGS<imp-def,dead>

llvm-svn: 62954

everything that we aren't intending to implement in Expr::Evaluate.

llvm-svn: 62953

cases it couldn't deal with before.

llvm-svn: 62952

accurately states what the function is trying to do and how it is 
different from Expr::isEvaluatable.  Also get rid of a parameter that is both 
unused and inaccurate.

llvm-svn: 62951

llvm-svn: 62950

__builtin___CFStringMakeConstantString.  (We get into trouble in 
GenerateStaticBlockVarDecl if the constant folder isn't accurate.)

llvm-svn: 62949

constant.

llvm-svn: 62948

llvm-svn: 62947

llvm-svn: 62946

for objc2's non-fragile abi.

llvm-svn: 62945

llvm-svn: 62944

think this has any significant effects at the moment, but it could 
matter if we start constant-folding statement expressions like gcc does.

llvm-svn: 62943

Note that there are still other issues in this area; see PR3396.

llvm-svn: 62942

sizeof expressions.

llvm-svn: 62941

llvm-svn: 62940

not the type" semantics.  This can definitely be improved, but is better than
what we had.

llvm-svn: 62939

more accurate change loses more than it gains on
benchmarks.

llvm-svn: 62938

llvm-svn: 62937

llvm-svn: 62936

of class in objc2's nonfragile abi.

llvm-svn: 62935

Add serialization support for ReferenceType.

llvm-svn: 62934

alignment must always be a constant.  Just let the constant folder 
do it.

llvm-svn: 62933

llvm-svn: 62932

llvm-svn: 62931

llvm-svn: 62930

implemented class in objc2's nonfrigile abi.

llvm-svn: 62929

different than those for sizeof.  Reject alignof(bitfield) like gcc does.

llvm-svn: 62928

llvm-svn: 62927

llvm-svn: 62926

llvm-svn: 62925

mismatched semantics).
 - Enforce this in APValue.

llvm-svn: 62924

llvm-svn: 62923

llvm-svn: 62922

llvm-svn: 62921

Also it was an empty struct, not a void after all.

llvm-svn: 62920

llvm-svn: 62919

Thus we need to check whether the struct is empty before trying to index into
it. This fixes PR3381.

llvm-svn: 62918

llvm-svn: 62917

llvm-svn: 62916

 - No functionality change, moved behind -use-x86_64-abi option until
   it becomes non-experimental.

llvm-svn: 62915