llvm-svn: 121944

llvm-svn: 121921

(performing the addition in a wider type and explicitly checking for overflow), and
fold them down to intrinsics.  This currently only supports signed-addition, but could
be generalized if someone works out the magic constant formulas for other operations.

Fixes <rdar://problem/8558713>.

llvm-svn: 121905

function so that it can live in Analysis instead of
VMCore.

llvm-svn: 121885

instcombine and into InstructionSimplify.

llvm-svn: 121861

Teach jump threading to "look through" a select when the branch direction of a terminator depends on it.
When it sees a promising select it now tries to figure out whether the condition of the select is known in any of the predecessors and if so it maps the operands appropriately.

llvm-svn: 121859

llvm-svn: 121838

this case involve a select that simplifies to itself.

llvm-svn: 121817

llvm-svn: 121816

   which is simpler than finding a place to insert in BB.
 - Don't perform the 'if condition hoisting' xform on certain
   i1 PHIs, as it interferes with switch formation.

This re-fixes "example 7", without breaking the world hopefully.

llvm-svn: 121764

first, it can kick in on blocks whose conditions have been
folded to a constant, even though one of the edges will be
trivially folded.

second, it doesn't clean up the "if diamond" that it just 
eliminated away.  This is a problem because other simplifycfg
xforms kick in depending on the order of block visitation,
causing pointless work.

llvm-svn: 121762

breaking the selfhost builds, though I can't fathom how.

llvm-svn: 121761

when all 2-entry phis are simplified away.

llvm-svn: 121760

don't print it unless the xform happens.

llvm-svn: 121758

llvm-svn: 121757

llvm-svn: 121756

llvm-svn: 121755

GetIfCondition faster by avoiding pred_iterator.  No
really interesting change.

llvm-svn: 121754

llvm-svn: 121753

code a bit, switch from constant folding to instsimplify.

llvm-svn: 121751

work, but fixes 400.perlbmk.

llvm-svn: 121749

Fix recent buildbot breakage by pulling SimplifyCFG back to its state as of r121694, the most recent state
where I'm confident there were no crashes or miscompilations.  XFAIL the test added since then for now.

llvm-svn: 121733

temporarily disable part of my previous patch, which causes an iterator invalidation issue, causing a crash on some versions of perlbmk.

llvm-svn: 121728

llvm-svn: 121711

llvm-svn: 121705

'and' case.

llvm-svn: 121695

I can track down a miscompile.  This should bring the buildbots
back to life

llvm-svn: 121693

when simplifying, allowing them to be eagerly turned into switches.  This
is the last step required to get "Example 7" from this blog post:
http://blog.regehr.org/archives/320

On X86, we now generate this machine code, which (to my eye) seems better
than the ICC generated code:

_crud:                                  ## @crud
## BB#0:                                ## %entry
	cmpb	$33, %dil
	jb	LBB0_4
## BB#1:                                ## %switch.early.test
	addb	$-34, %dil
	cmpb	$58, %dil
	ja	LBB0_3
## BB#2:                                ## %switch.early.test
	movzbl	%dil, %eax
	movabsq	$288230376537592865, %rcx ## imm = 0x400000017001421
	btq	%rax, %rcx
	jb	LBB0_4
LBB0_3:                                 ## %lor.rhs
	xorl	%eax, %eax
	ret
LBB0_4:                                 ## %lor.end
	movl	$1, %eax
	ret

llvm-svn: 121690

llvm-svn: 121689

per terminator kind.

llvm-svn: 121688

llvm-svn: 121687

doing a cfg search for every block simplified.

llvm-svn: 121686

llvm-svn: 121685

llvm-svn: 121684

getSinglePredecessor to simplify code.

llvm-svn: 121683

llvm-svn: 121681

'or sequence' that it doesn't understand.  This allows us to optimize
something insane like this:

int crud (unsigned char c, unsigned x)
 {
   if(((((((((( (int) c <= 32 ||
                    (int) c == 46) || (int) c == 44)
                  || (int) c == 58) || (int) c == 59) || (int) c == 60)
               || (int) c == 62) || (int) c == 34) || (int) c == 92)
            || (int) c == 39) != 0)
     foo();
 }

into:

define i32 @crud(i8 zeroext %c, i32 %x) nounwind ssp noredzone {
entry:
  %cmp = icmp ult i8 %c, 33
  br i1 %cmp, label %if.then, label %switch.early.test

switch.early.test:                                ; preds = %entry
  switch i8 %c, label %if.end [
    i8 39, label %if.then
    i8 44, label %if.then
    i8 58, label %if.then
    i8 59, label %if.then
    i8 60, label %if.then
    i8 62, label %if.then
    i8 46, label %if.then
    i8 92, label %if.then
    i8 34, label %if.then
  ]

by pulling the < comparison out ahead of the newly formed switch.

llvm-svn: 121680

llvm-svn: 121678

llvm-svn: 121676

llvm-svn: 121675