It's not safe to use the two value CombineTo variant to combine away a dead load.
e.g. 
v1, chain2 = load chain1, loc
v2, chain3 = load chain2, loc
v3         = add v2, c 
Now we replace use of v1 with undef, use of chain2 with chain1.
ReplaceAllUsesWith() will iterate through uses of the first load and update operands:
v1, chain2 = load chain1, loc
v2, chain3 = load chain1, loc
v3         = add v2, c 
Now the second load is the same as the first load, SelectionDAG cse will ensure
the use of second load is replaced with the first load.
v1, chain2 = load chain1, loc
v3         = add v1, c
Then v1 is replaced with undef and bad things happen.

llvm-svn: 46099

it should work, but I have no machine to test
it on.  Committed because it will at least
cause no harm, and maybe someone can test it
for me!

llvm-svn: 46098

llvm-svn: 46090

associated function is so marked.

llvm-svn: 46088

simplification.  This fixes automotive-basicmath on PPC.

llvm-svn: 46072

pattern to use EmitStackConvert now.

llvm-svn: 46066

it to allow it to emit different load and store kinds.

llvm-svn: 46065

instead of inlining its body.

llvm-svn: 46062

into the ANY_EXTEND/ZERO_EXTEND/SIGN_EXTEND code to simplify it.

Unmerge the code for FP_ROUND and FP_EXTEND from each other to 
make each one simpler.

llvm-svn: 46061

llvm-svn: 46058

some code.  No functionality change.

llvm-svn: 46055

make the 'fp return in ST(0)' optimization smart enough to
look through token factor nodes.  THis allows us to compile 
testcases like CodeGen/X86/fp-stack-retcopy.ll into:

_carg:
	subl	$12, %esp
	call	L_foo$stub
	fstpl	(%esp)
	fldl	(%esp)
	addl	$12, %esp
	ret

instead of:

_carg:
	subl	$28, %esp
	call	L_foo$stub
	fstpl	16(%esp)
	movsd	16(%esp), %xmm0
	movsd	%xmm0, 8(%esp)
	fldl	8(%esp)
	addl	$28, %esp
	ret

Still not optimal, but much better and this is a trivial patch.  Fixing 
the rest requires invasive surgery that is is not llvm 2.2 material.

llvm-svn: 46054

look through token factor

llvm-svn: 46053

llvm-svn: 46052

a public SDOperand::reachesChainWithoutSideEffects method.  No 
functionality change.

llvm-svn: 46050

llvm-svn: 46045

llvm-svn: 46030

ShortenEHDataFor64Bits as a not-very-accurate
abstraction to cover all the changes in DwarfWriter.
Some cosmetic changes to Darwin assembly code for
gcc testsuite compatibility.

llvm-svn: 46029

Move some calls to getVRegDef higher in the callgraph, so they don't get executed as frequently in performance sensitive code.

llvm-svn: 46027

llvm-svn: 46026

llvm-svn: 46019

it's a function pointer) not MVT::Other.  This fixes builtin_trap
lowering on ppc, alpha, ia64

llvm-svn: 46018

Move definition of 'trap' sdnode up from x86 instrinfo to targetselectiondag.td.

llvm-svn: 46017

llvm-svn: 46016

llvm-svn: 46015

llvm-svn: 46014

llvm-svn: 46012

llvm-svn: 46009

llvm-svn: 46002

as well as PPC codegen

llvm-svn: 46001

Rename CCIfStruct to CCIfByVal and CCStructAssign to CCPassByVal. Remove unused parameters of CCStructAssign and add size and alignment requirement info.

llvm-svn: 45997

llvm-svn: 45996

llvm-svn: 45995

llvm-svn: 45974

drop attributes on varargs call arguments.  Also, it could generate
invalid IR if the transformed call already had the 'nest' attribute
somewhere (this can never happen for code coming from llvm-gcc,
but it's a theoretical possibility).  Fix both problems.

llvm-svn: 45973

llvm-svn: 45972

llvm-svn: 45971

an instruction kills a register or not.  This is cheap and 
easy to do now that instructions record this on their flags,
and this eliminates the second pass of LiveVariables from the
x86 backend.  This speeds up a release llc by ~2.5%.

llvm-svn: 45955

llvm-svn: 45950

byval work.  This miscompilation is due to the program indexing an array out
of range and us doing a transformation that broke this.

llvm-svn: 45949