Optimize code placement in loop to eliminate unconditional branches or move unconditional branch to the outside of the loop. e.g.

///       A:                                                                                                                                                                 
///       ...                                                                                                                                                                
///       <fallthrough to B>                                                                                                                                                 
///                                                                                                                                                                          
///       B:  --> loop header                                                                                                                                                
///       ...                                                                                                                                                                
///       jcc <cond> C, [exit]                                                                                                                                               
///                                                                                                                                                                          
///       C:                                                                                                                                                                 
///       ...                                                                                                                                                                
///       jmp B                                                                                                                                                              
///                                                                                                                                                                          
/// ==>                                                                                                                                                                      
///                                                                                                                                                                          
///       A:                                                                                                                                                                 
///       ...                                                                                                                                                                
///       jmp B                                                                                                                                                              
///                                                                                                                                                                          
///       C:  --> new loop header                                                                                                                                            
///       ...                                                                                                                                                                
///       <fallthough to B>                                                                                                                                                  
///                                                                                                                                                                          
///       B:                                                                                                                                                                 
///       ...                                                                                                                                                                
///       jcc <cond> C, [exit] 

llvm-svn: 71209

build under gcc 4.3.

llvm-svn: 71208

No functionality change.

llvm-svn: 71207

llvm-svn: 71206

llvm-svn: 71205

llvm-svn: 71202

llvm-svn: 71201

implicitly be changed to unsigned values in GRSimpleVals.cpp. This can happen
when the comparison involves logic in specialized transfer functions (e.g.,
OSAtomicCompareAndSwap).

llvm-svn: 71200

llvm-svn: 71199

"This patch is a first pass at adding support for exceptions for the GNU runtime.  There are a few limitations at present:

- @synchronized() is not yet supported at all.  gcc currently emits calls to runtime library functions that don't exist for this directive.

- Only id @catch statements are currently working.  This is enough for NS_DURING and friends, but I need to spend more time reading the output from gcc -S to work out how it finds the class pointer to make arbitrary class type catch statements work.

- I've tested it with a few common cases[1] and the clang test suite (which doesn't test exceptions for the GNU runtime, but shows I haven't broken anything else), but there are probably a lot of cases I've missed."

Patch by David Chisnall!

llvm-svn: 71198

scavenger gets confused about register liveness if it doesn't see them.
I'm not thrilled with this solution, but it only comes up when there are dead
copies in the code, which is something that hopefully doesn't happen much.

Here is what happens in pr4100: As shown in the following excerpt from the
debug output of llc, the source of a move gets reloaded from the stack,
inserting a new load instruction before the move.  Since that source operand
is a kill, the physical register is free to be reused for the destination
of the move.  The move ends up being a no-op, copying R3 to R3, so it is
deleted.  But, it leaves behind the load to reload %reg1028 into R3, and
that load is not updated to show that it's destination operand (R3) is dead.
The scavenger gets confused by that load because it thinks that R3 is live.

Starting RegAlloc of: %reg1025<def,dead> = MOVr %reg1028<kill>, 14, %reg0, %reg0
  Regs have values: 
  Reloading %reg1028 into R3
  Last use of R3[%reg1028], removing it from live set
  Assigning R3 to %reg1025
  Register R3 [%reg1025] is never used, removing it from live set

Alternative solutions might be either marking the load as dead, or zapping
the load along with the no-op copy.  I couldn't see an easy way to do
either of those, though.

llvm-svn: 71196

llvm-svn: 71194

other changes.  Instead of repeatedly checking for GC mode when
getting the return effect, just do this computation once.

llvm-svn: 71193

 - Support generating structures with bit-fields.

llvm-svn: 71192

block pointer.  Radar 6441502

llvm-svn: 71190

llvm-svn: 71184

llvm-svn: 71183

- Rename 'ns_returns_owned' -> 'ns_returns_retained'.
- Rename 'cf_returns_owned' -> 'cf_returns_retained'.

llvm-svn: 71182

refers to the underlying class.
This is radar 6859726. Steve, please read the radar for my rational.

llvm-svn: 71181

llvm-svn: 71180

llvm-svn: 71179

several regressions. The problem due to 71158 is now fixed.

llvm-svn: 71176

types, such as loads and calls.

llvm-svn: 71175

llvm-svn: 71174

the SCEVUDivExpr case.

llvm-svn: 71173

llvm-svn: 71172

llvm-svn: 71171

analysis introspection) when we computed an lvalue.  This shouldn't
effect the current analysis results in any way.

llvm-svn: 71169

bits captured, but the pointer marked nocapture.  In fact
I now recall that this problem is why only readnone functions
returning void were considered before!  However keep a small
fix that was also in r70876: a readnone function returning
void can result in bits being captured if it unwinds, so
test for this.

llvm-svn: 71168

development. Still much more to write!

llvm-svn: 71167

checking for bcopy... no
checking for getc_unlocked... Assertion failed: (0 && "Unknown SCEV kind!"), function operator(), file /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmCore.roots/llvmCore~obj/src/lib/Analysis/ScalarEvolution.cpp, line 511.
/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmgcc42.roots/llvmgcc42~obj/src/libdecnumber/decUtility.c:360: internal compiler error: Abort trap
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://developer.apple.com/bugreporter> for instructions.
make[4]: *** [decUtility.o] Error 1
make[4]: *** Waiting for unfinished jobs....
Assertion failed: (0 && "Unknown SCEV kind!"), function operator(), file /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmCore.roots/llvmCore~obj/src/lib/Analysis/ScalarEvolution.cpp, line 511.
/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmgcc42.roots/llvmgcc42~obj/src/libdecnumber/decNumber.c:5591: internal compiler error: Abort trap
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://developer.apple.com/bugreporter> for instructions.
make[4]: *** [decNumber.o] Error 1
make[3]: *** [all-stage2-libdecnumber] Error 2
make[3]: *** Waiting for unfinished jobs....

llvm-svn: 71165

llvm-svn: 71163

llvm-svn: 71162

llvm-svn: 71161

to sorting SCEVs by their kind, sort SCEVs of the same kind according
to their operands. This helps avoid things like (a+b) being a distinct
expression from (b+a).

llvm-svn: 71160

headers due to library dependencies.

llvm-svn: 71159

array and the add is within range. This helps simplify expressions
expanded by ScalarEvolutionExpander.

llvm-svn: 71158

SCEVAddRecExpr. This eliminates redundant code for visiting
all the operands of an expression.

llvm-svn: 71157

No functionality change.

llvm-svn: 71156

specialization type for a dependent template name.

llvm-svn: 71153