have objectsize folding recursively simplify away their result when it
folds.  It is important to catch this here, because otherwise we won't
eliminate the cross-block values at isel and other times.

llvm-svn: 123524

potentially invalidate it (like inline asm lowering) to be sunk into
their proper place, cleaning up a ton of code.

llvm-svn: 123523

This fixes rdar://8808586 which observed that we used to compile:


union xy {
        struct x { _Bool b[15]; } x;
        __attribute__((packed))
        struct y {
                __attribute__((packed)) unsigned long b0to7;
                __attribute__((packed)) unsigned int b8to11;
                __attribute__((packed)) unsigned short b12to13;
                __attribute__((packed)) unsigned char b14;
        } y;
};

struct x
foo(union xy *xy)
{
        return xy->x;
}

into:

_foo:                                   ## @foo
	movq	(%rdi), %rax
	movabsq	$1095216660480, %rcx    ## imm = 0xFF00000000
	andq	%rax, %rcx
	movabsq	$-72057594037927936, %rdx ## imm = 0xFF00000000000000
	andq	%rax, %rdx
	movzbl	%al, %esi
	orq	%rdx, %rsi
	movq	%rax, %rdx
	andq	$65280, %rdx            ## imm = 0xFF00
	orq	%rsi, %rdx
	movq	%rax, %rsi
	andq	$16711680, %rsi         ## imm = 0xFF0000
	orq	%rdx, %rsi
	movl	%eax, %edx
	andl	$-16777216, %edx        ## imm = 0xFFFFFFFFFF000000
	orq	%rsi, %rdx
	orq	%rcx, %rdx
	movabsq	$280375465082880, %rcx  ## imm = 0xFF0000000000
	movq	%rax, %rsi
	andq	%rcx, %rsi
	orq	%rdx, %rsi
	movabsq	$71776119061217280, %r8 ## imm = 0xFF000000000000
	andq	%r8, %rax
	orq	%rsi, %rax
	movzwl	12(%rdi), %edx
	movzbl	14(%rdi), %esi
	shlq	$16, %rsi
	orl	%edx, %esi
	movq	%rsi, %r9
	shlq	$32, %r9
	movl	8(%rdi), %edx
	orq	%r9, %rdx
	andq	%rdx, %rcx
	movzbl	%sil, %esi
	shlq	$32, %rsi
	orq	%rcx, %rsi
	movl	%edx, %ecx
	andl	$-16777216, %ecx        ## imm = 0xFFFFFFFFFF000000
	orq	%rsi, %rcx
	movq	%rdx, %rsi
	andq	$16711680, %rsi         ## imm = 0xFF0000
	orq	%rcx, %rsi
	movq	%rdx, %rcx
	andq	$65280, %rcx            ## imm = 0xFF00
	orq	%rsi, %rcx
	movzbl	%dl, %esi
	orq	%rcx, %rsi
	andq	%r8, %rdx
	orq	%rsi, %rdx
	ret

We now compile this into:

_foo:                                   ## @foo
## BB#0:                                ## %entry
	movzwl	12(%rdi), %eax
	movzbl	14(%rdi), %ecx
	shlq	$16, %rcx
	orl	%eax, %ecx
	shlq	$32, %rcx
	movl	8(%rdi), %edx
	orq	%rcx, %rdx
	movq	(%rdi), %rax
	ret

A small improvement :-)

llvm-svn: 123520

no functionality change currently.

llvm-svn: 123517

llvm-svn: 123516

means that are about to disappear.

llvm-svn: 123515

llvm-svn: 123514

llvm-svn: 123505

to use it.

llvm-svn: 123501

llvm-svn: 123497

llvm-svn: 123494

llvm-svn: 123491

declaration and its assignments.

Found by clang static analyzer.

llvm-svn: 123486

llvm-svn: 123480

comments.

llvm-svn: 123479

bitcasts, at least in simple cases.  This fixes clang's CodeGenCXX/virtual-base-dtor.cpp

llvm-svn: 123477

Add a possibility to switch between CFI directives- and table-based frame description emission. Currently all the backends use table-based stuff.

llvm-svn: 123476

llvm-svn: 123475

llvm-svn: 123474

llvm-svn: 123473

llvm-svn: 123472

disabled in this checkin. Sorry for the large diffs due to
refactoring. New functionality is all guarded by EnableSchedCycles.

Scheduling the isel DAG is inherently imprecise, but we give it a best
effort:
- Added MayReduceRegPressure to allow stalled nodes in the queue only
  if there is a regpressure need.
- Added BUHasStall to allow checking for either dependence stalls due to
  latency or resource stalls due to pipeline hazards.
- Added BUCompareLatency to encapsulate and standardize the heuristics
  for minimizing stall cycles (vs. reducing register pressure).
- Modified the bottom-up heuristic (now in BUCompareLatency) to
  prioritize nodes by their depth rather than height. As long as it
  doesn't stall, height is irrelevant. Depth represents the critical
  path to the DAG root.
- Added hybrid_ls_rr_sort::isReady to filter stalled nodes before
  adding them to the available queue.

Related Cleanup: most of the register reduction routines do not need
to be templates.

llvm-svn: 123468

llvm-svn: 123457

"promote a bunch of load and stores" logic, allowing the code to
be shared and reused.

llvm-svn: 123456

simplification present in fully optimized code (I think instcombine fails to
transform some of these when "X-Y" has more than one use).  Fires here and
there all over the test-suite, for example it eliminates 8 subtractions in
the final IR for 445.gobmk, 2 subs in 447.dealII, 2 in paq8p etc.

llvm-svn: 123442

threading of shifts over selects and phis while there.  This fires here and
there in the testsuite, to not much effect.  For example when compiling spirit
it fires 5 times, during early-cse, resulting in 6 more cse simplifications,
and 3 more terminators being folded by jump threading, but the final bitcode
doesn't change in any interesting way: other optimizations would have caught
the opportunity anyway, only later.

llvm-svn: 123441

and one that uses SSAUpdater (-scalarrepl-ssa)

llvm-svn: 123436

static_cast from Constant* to Value* has to adjust the "this" pointer.
This is groundwork for PR889.

llvm-svn: 123435

instead of DomTree/DomFrontier.  This may be interesting for reducing compile 
time.  This is currently disabled, but seems to work just fine.

When this is enabled, we eliminate two runs of dominator frontier, one in the
"early per-function" optimizations and one in the "interlaced with inliner"
function passes.

llvm-svn: 123434

This time let's rephrase to trick gcc-4.3 into not miscompiling.

llvm-svn: 123432

llvm-gcc-i386-linux-selfhost buildbot heartburn...

llvm-svn: 123431

llvm-svn: 123427

llvm-svn: 123426

- Fixed :upper16: fix up routine. It should be shifting down the top 16 bits first.
- Added support for Thumb2 :lower16: and :upper16: fix up.
- Added :upper16: and :lower16: relocation support to mach-o object writer.

llvm-svn: 123424

llvm-svn: 123423

llvm-svn: 123422

they should go *before* the new instruction not after it. 

llvm-svn: 123420

Fix some callers to better deal with debug values.

llvm-svn: 123419

While there, I noticed that the transform "undef >>a X -> undef" was wrong.
For example if X is 2 then the top two bits must be equal, so the result can
not be anything.  I fixed this in the constant folder as well.  Also, I made
the transform for "X << undef" stronger: it now folds to undef always, even
though X might be zero.  This is in accordance with the LangRef, but I must
admit that it is fairly aggressive.  Also, I added "i32 X << 32 -> undef"
following the LangRef and the constant folder, likewise fairly aggressive.

llvm-svn: 123417

after sext's generated for addressing that got folded.  Previously we compiled
test5 into:

_test5:                                 ## @test5
## BB#0:
        movq    -8(%rsp), %rax          ## 8-byte Reload
        movq    (%rdi,%rax), %rdi
        addq    %rdx, %rdi
        movslq  %esi, %rax
        movq    %rax, -8(%rsp)          ## 8-byte Spill
        movq    %rdi, %rax
        ret

which is insane and wrong.  Now we produce:

_test5:                                 ## @test5
## BB#0:
	movslq	%esi, %rax
	movq	(%rdi,%rax), %rax
	addq	%rdx, %rax
	ret

llvm-svn: 123414