enough to teach it that ADDE(0,0) is known 0 except the 
low bit, for example.

llvm-svn: 122191

llvm-svn: 122190

we don't need -disable-mmx anymore.

llvm-svn: 122189

tests don't need -disable-mmx.

llvm-svn: 122188

llvm-svn: 122187

generate them.  

Now we compile:

define zeroext i8 @X(i8 signext %a, i8 signext %b) nounwind ssp {
entry:
  %0 = tail call %0 @llvm.sadd.with.overflow.i8(i8 %a, i8 %b)
  %cmp = extractvalue %0 %0, 1
  br i1 %cmp, label %if.then, label %if.end

into:

_X:                                     ## @X
## BB#0:                                ## %entry
	subl	$12, %esp
	movb	16(%esp), %al
	addb	20(%esp), %al
	jo	LBB0_2

Before we were generating:

_X:                                     ## @X
## BB#0:                                ## %entry
	pushl	%ebp
	movl	%esp, %ebp
	subl	$8, %esp
	movb	12(%ebp), %al
	testb	%al, %al
	setge	%cl
	movb	8(%ebp), %dl
	testb	%dl, %dl
	setge	%ah
	cmpb	%cl, %ah
	sete	%cl
	addb	%al, %dl
	testb	%dl, %dl
	setge	%al
	cmpb	%al, %ah
	setne	%al
	andb	%cl, %al
	testb	%al, %al
	jne	LBB0_2

llvm-svn: 122186

llvm-svn: 122185

llvm-svn: 122183

This resolves a README entry and technically resolves PR4916,
but we still get poor code for the testcase in that PR because
GVN isn't CSE'ing uadd with add, filed as PR8817.

Previously we got:

_test7:                                 ## @test7
	addq	%rsi, %rdi
	cmpq	%rdi, %rsi
	movl	$42, %eax
	cmovaq	%rsi, %rax
	ret

Now we get:

_test7:                                 ## @test7
	addq	%rsi, %rdi
	movl	$42, %eax
	cmovbq	%rsi, %rax
	ret

llvm-svn: 122182

result is dead.  This is required for my next patch to not
regress the testsuite.

llvm-svn: 122181

llvm-svn: 122180

the old thing end up on the instcombine worklist.  Not doing this
can cause an extra top-level iteration of instcombine, burning
compile time.

llvm-svn: 122179

sadd formed is half the size of the original type. We can
now compile this into a sadd.i8:

unsigned char X(char a, char b) {
  int res = a+b;
  if ((unsigned )(res+128) > 255U)
    abort();
  return res;
}

llvm-svn: 122178

checking to see if the high bits of the original add result were dead.
Inserting a smaller add and zexting back to that size is not good enough.

This is likely to be the fix for 8816.

llvm-svn: 122177

alternative register allocator that does not require LiveIntervals by specifying
it on the command-line for a target that has StrongPHIElimination enabled by
default.

These checks are pretty meaningless anyways, since StrongPHIElimination and
PHIElimination are never used at the same time.

llvm-svn: 122176

profitable (or safe) to promote code when the add-with-constant
has other uses.

llvm-svn: 122175

helper function, clean up comments, and reduce indentation.
No functionality change.

llvm-svn: 122174

which doesn't affect the memory address being promoted.

llvm-svn: 122172

does not make the alias set for that pointer volatile, just stores
*to* the pointer.

llvm-svn: 122171

isel is *required* to split the edge.  PHI values get evaluated
on the edge, not in their predecessor block.

llvm-svn: 122170

llvm-svn: 122169

llvm-svn: 122168

llvm-svn: 122167

llvm-svn: 122165

which have trapping constant exprs in them due to PHI nodes.
Eliminating them can cause the constant expr to be evalutated
on new paths if the input edges are critical.

llvm-svn: 122164

is enabled.

llvm-svn: 122163

llvm-svn: 122160

llvm-svn: 122159

llvm-svn: 122158

llvm-svn: 122157

llvm-svn: 122156

It turns out that ppc backend has really weird interdependencies
over different hooks and all stuff is fragile wrt small changes.
This should fix PR8749

llvm-svn: 122155

Just rename the functions, relying on matching a instruction that has the same name as a symbol is way too fragile.

llvm-svn: 122154

llvm-svn: 122153

llvm-svn: 122152

This fixed 8615.

llvm-svn: 122150

the buildbots.

llvm-svn: 122149

llvm-svn: 122148

llvm-svn: 122147

of two symbols in the same fragment.

llvm-svn: 122145