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: 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

the SCEVUDivExpr case.

llvm-svn: 71173

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

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

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

llvm-svn: 71151

llvm-svn: 71150

llvm-svn: 71149

llvm-svn: 71140

llvm-svn: 71138

-Have it return a label ID
-Remove the unused Instruction parameter

No functionality change.

llvm-svn: 71132

trivially different code on different hosts (due to differing
std::sort implementations).

llvm-svn: 71124

  change.
- Reformatting.

llvm-svn: 71118

llvm-svn: 71115

more place.  This fixes a bunch of x86-64 JIT regressions.
(Introduced when the value of the magic constant changed
in 68645.  At the time apparently nobody noticed; failures
were hidden in 70343-70439 by an unrelated bug, so showed
up again as "new" failures in 70440.)

llvm-svn: 71106

llvm-svn: 71098

llvm-svn: 71091

Make sure to use signed arithmetic in APInt to fix a regression.

llvm-svn: 71090

separate back() and pop_back() calls.

llvm-svn: 71089

llvm-svn: 71085

Incomplete, but better than nothing.

llvm-svn: 71081

are legal.  Based on a patch by Micah Villmow.

llvm-svn: 71078

the readnone.  Since MallocInst is scheduled for deletion
it doesn't seem worth doing anything more subtle, such as
having mayWriteToMemory return true for MallocInst.

llvm-svn: 71077

Split large global data (both initialized and un-initialized) into multiple sections of <= 80 bytes.
Provide routines to manage PIC16 ABI naming conventions.

llvm-svn: 71073

the optimizers about this.  For example, a readonly
function with no uses cannot be removed unless it is
also marked nounwind.

llvm-svn: 71071

llvm-svn: 71057

llvm-svn: 71035

llvm-svn: 71033

llvm-svn: 71032

llvm-svn: 71028

allow it to have multiple CFG edges to that block. This is needed
to allow MachineBasicBlock::isOnlyReachableByFallthrough to work
correctly. This fixes PR4126.

llvm-svn: 71018

Running /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm.src/test/
CodeGen/X86/dg.exp ...
FAIL: /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm.src/test/
CodeGen/X86/change-compare-stride-1.ll
Failed with exit(1) at line 2
while running: grep {cmpq       $-478,} change-compare-stride-1.ll.tmp
child process exited abnormally

llvm-svn: 71013