This looks like it flagged an actual bug. Devang, please review. I added
the parentheses that change behavior, but make the behavior more closely
match commit log's intent.

llvm-svn: 132165

llvm-svn: 132164

crc32.[8|16|32] have been renamed to .crc32.32.[8|16|32] and
crc64.[8|16|32] have been renamed to .crc32.64.[8|64].

llvm-svn: 132163

llvm-svn: 132161

If llvm.dbg.value and the value instruction it refers to are far apart then iSel may not be able to find corresponding Node for llvm.dbg.value during DAG construction. Make iSel's life easier by removing this distance between llvm.dbg.value and its value instruction.

llvm-svn: 132151

Use a proper worklist for use-def traversal without holding onto an
iterator. Now that we process all IV uses, we need complete logic for
resusing existing derived IV defs. See HoistStep.

llvm-svn: 132103

llvm-svn: 132097

llvm-svn: 132071

cleanup and overdue test cases.

llvm-svn: 132038

llvm-svn: 132025

case of a switch instruction. Back off this optimization when this would
eliminate all of the predecessors to the latch.

Sorry, I am unable to reduce a reasonably sized test case.

rdar://9486843

llvm-svn: 132022

Make instcombine O(N) instead of O(N^2) in code where the same simplifiable constant is used many times.
Part of rdar://9471075.

llvm-svn: 131979

llvm-svn: 131956

promoting allocas to SSA variables. Fixes <rdar://problem/9479036>.

llvm-svn: 131953

This fixes PR9845.

llvm-svn: 131919

xform recurse.

llvm-svn: 131888

in a known-non-zero context.

llvm-svn: 131887

for a constant directly.  Thanks to Duncan for pointing this out.

llvm-svn: 131885

aligned.

Teach memcpyopt to not give up all hope when confonted with an underaligned
memcpy feeding an overaligned byval.  If the *source* of the memcpy can be
determined to be adequeately aligned, or if it can be forced to be, we can
eliminate the memcpy.

This addresses PR9794.  We now compile the example into:

define i32 @f(%struct.p* nocapture byval align 8 %q) nounwind ssp {
entry:
  %call = call i32 @g(%struct.p* byval align 8 %q) nounwind
  ret i32 %call
}

in both x86-64 and x86-32 mode.  We still don't get a tailcall though,
because tailcalls apparently can't handle byval.

llvm-svn: 131884

llvm-svn: 131862

result is non-zero.  Implement an example optimization (PR9814), which allows us to
transform:
  A / ((1 << B) >>u 2)
into:
  A >>u (B-2)

which we compile into:

_divu3:                                 ## @divu3
	leal	-2(%rsi), %ecx
	shrl	%cl, %edi
	movl	%edi, %eax
	ret

instead of:

_divu3:                                 ## @divu3
	movb	%sil, %cl
	movl	$1, %esi
	shll	%cl, %esi
	shrl	$2, %esi
	movl	%edi, %eax
	xorl	%edx, %edx
	divl	%esi, %eax
	ret

llvm-svn: 131860

failing to form a memset, then having to delete it" but my approximation
isn't safe for self recurrent loops.  Instead of doign a hack, just
do it the right way.

llvm-svn: 131858

Add a parameter to ConstantFoldTerminator() that callers can use to ask it to also clean up the condition of any conditional terminator it folds to be unconditional, if that turns the condition into dead code. This just means it calls RecursivelyDeleteTriviallyDeadInstructions() in strategic spots. It defaults to the old behavior.

I also changed -simplifycfg, -jump-threading and -codegenprepare to use this to produce slightly better code without any extra cleanup passes (AFAICT this was the only place in -simplifycfg where now-dead conditions of replaced terminators weren't being cleaned up). The only other user of this function is -sccp, but I didn't read that thoroughly enough to figure out whether it might be holding pointers to instructions that could be deleted by this.

llvm-svn: 131855

"stored once" even if its address is compared.

llvm-svn: 131849

causing it to get into infinite loops when it would widen a 
load (which can necessarily leave around dead loads).

llvm-svn: 131847

of the inlinee to the code representing the original function.

llvm-svn: 131838

consistently.

llvm-svn: 131803

It's better to do this in codegen, mul.with.overflow(X, 2) is more canonical because it has only one use on "X".

llvm-svn: 131798

llvm-svn: 131789

No functionality enabled by default. Use -disable-iv-rewrite.
Extended IVUsers to keep track of the phi that represents the users' IV.
Added the WidenIV transform to replace a narrow IV with a wide IV
by doing a one-for-one replacement of IV users instead of expanding the
SCEV expressions. [sz]exts are removed and truncs are inserted.

llvm-svn: 131744

llvm-svn: 131716

llvm-svn: 131708

Reapply r131605. This time with a fix, which is to use NoFolder.

llvm-svn: 131673

llvm-svn: 131659

llvm-svn: 131620

I'm not sure this is quite ideal, but I can't really think of any better way to do it.

llvm-svn: 131616

llvm-svn: 131609

llvm-svn: 131607

llvm-svn: 131605

llvm-svn: 131604