(x > y) ? x : y
=>
(x >= y) ? x : y
So for something like
(x - y) > 0 : (x - y) ? 0
It will be
(x - y) >= 0 : (x - y) ? 0
This makes is possible to test sign-bit and eliminate a comparison against
zero. e.g.
subl %esi, %edi
testl %edi, %edi
movl $0, %eax
cmovgl %edi, %eax
=>
xorl %eax, %eax
subl %esi, $edi
cmovsl %eax, %edi
rdar://10633221
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147512 91177308-0d34-0410-b5e6-96231b3b80d8
This patch caused a miscompilation of oggenc because a frame pointer was
suddenly needed halfway through register allocation.
<rdar://problem/10625436>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147487 91177308-0d34-0410-b5e6-96231b3b80d8
The failure seen on win32, when i64 type is illegal.
It happens on stage of conversion VECTOR_SHUFFLE to BUILD_VECTOR.
The failure message is:
llc: SelectionDAG.cpp:784: void VerifyNodeCommon(llvm::SDNode*): Assertion `(I->getValueType() == EltVT || (EltVT.isInteger() && I->getValueType().isInteger() && EltVT.bitsLE(I->getValueType()))) && "Wrong operand type!"' failed.
I added a special test that checks vector shuffle on win32.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147445 91177308-0d34-0410-b5e6-96231b3b80d8
The failure seen on win32, when i64 type is illegal.
It happens on stage of conversion VECTOR_SHUFFLE to BUILD_VECTOR.
The failure message is:
llc: SelectionDAG.cpp:784: void VerifyNodeCommon(llvm::SDNode*): Assertion `(I->getValueType() == EltVT || (EltVT.isInteger() && I->getValueType().isInteger() && EltVT.bitsLE(I->getValueType()))) && "Wrong operand type!"' failed.
I added a special test that checks vector shuffle on win32.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147399 91177308-0d34-0410-b5e6-96231b3b80d8
1. The ST*UX instructions that store and update the stack pointer did not set define/kill on R1. This became a problem when I activated post-RA scheduling (and had incorrectly adjusted the Frames-large test).
2. eliminateFrameIndex did not kill its scavenged temporary register, and this could cause the scavenger to exhaust all available registers (and its emergency spill slot) when there were a lot of CR values to spill. The 2010-02-12-saveCR test has been adjusted to check for this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147359 91177308-0d34-0410-b5e6-96231b3b80d8
Promotion of the mask operand needs to be done using PromoteTargetBoolean, and not padded with garbage.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147309 91177308-0d34-0410-b5e6-96231b3b80d8
Matching MOVLP mask for AVX (265-bit vectors) was wrong.
The failure was detected by conformance tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147308 91177308-0d34-0410-b5e6-96231b3b80d8
LZCNT instructions are available. Force promotion to i32 to get
a smaller encoding since the fix-ups necessary are just as complex for
either promoted type
We can't do standard promotion for CTLZ when lowering through BSR
because it results in poor code surrounding the 'xor' at the end of this
instruction. Essentially, if we promote the entire CTLZ node to i32, we
end up doing the xor on a 32-bit CTLZ implementation, and then
subtracting appropriately to get back to an i8 value. Instead, our
custom logic just uses the knowledge of the incoming size to compute
a perfect xor. I'd love to know of a way to fix this, but so far I'm
drawing a blank. I suspect the legalizer could be more clever and/or it
could collude with the DAG combiner, but how... ;]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147251 91177308-0d34-0410-b5e6-96231b3b80d8
my C-brain happy. Remove the unnecessary bits of pedantic IR fluff like
nounwind. Remove stray uses comments. Name things semantically rather
than tN so that adding a new test in the middle doesn't cause pain, and
so that new tests can be grouped semantically.
This exposes how little systematic testing is going on here. I noticed
this by finding several bugs via inspection and wondering why this test
wasn't catching any of them. =[
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147248 91177308-0d34-0410-b5e6-96231b3b80d8
'bsf' instructions here.
This one is actually debatable to my eyes. It's not clear that any chip
implementing 'tzcnt' would have a slow 'bsf' for any reason, and unless
EFLAGS or a zero input matters, 'tzcnt' is just a longer encoding.
Still, this restores the old behavior with 'tzcnt' enabled for now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147246 91177308-0d34-0410-b5e6-96231b3b80d8
X86ISelLowering C++ code. Because this is lowered via an xor wrapped
around a bsr, we want the dagcombine which runs after isel lowering to
have a chance to clean things up. In particular, it is very common to
see code which looks like:
(sizeof(x)*8 - 1) ^ __builtin_clz(x)
Which is trying to compute the most significant bit of 'x'. That's
actually the value computed directly by the 'bsr' instruction, but if we
match it too late, we'll get completely redundant xor instructions.
The more naive code for the above (subtracting rather than using an xor)
still isn't handled correctly due to the dagcombine getting confused.
Also, while here fix an issue spotted by inspection: we should have been
expanding the zero-undef variants to the normal variants when there is
an 'lzcnt' instruction. Do so, and test for this. We don't want to
generate unnecessary 'bsr' instructions.
These two changes fix some regressions in encoding and decoding
benchmarks. However, there is still a *lot* to be improve on in this
type of code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147244 91177308-0d34-0410-b5e6-96231b3b80d8
ARM targets with NEON units have access to aligned vector loads and
stores that are potentially faster than unaligned operations.
Add support for spilling the callee-saved NEON registers to an aligned
stack area using 16-byte aligned NEON loads and store.
This feature is off by default, controlled by an -align-neon-spills
command line option.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147211 91177308-0d34-0410-b5e6-96231b3b80d8
Use the spill slot alignment as well as the local variable alignment to
determine when the stack needs to be realigned. This works now that the
ARM target can always realign the stack by using a base pointer.
Still respect the ARMBaseRegisterInfo::canRealignStack() function
vetoing a realigned stack. Don't use aligned spill code in that case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146997 91177308-0d34-0410-b5e6-96231b3b80d8
use the zero-undefined variants of CTTZ and CTLZ. These are just simple
patterns for now, there is more to be done to make real world code using
these constructs be optimized and codegen'ed properly on X86.
The existing tests are spiffed up to check that we no longer generate
unnecessary cmov instructions, and that we generate the very important
'xor' to transform bsr which counts the index of the most significant
one bit to the number of leading (most significant) zero bits. Also they
now check that when the variant with defined zero result is used, the
cmov is still produced.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146974 91177308-0d34-0410-b5e6-96231b3b80d8
We used to rely on the *eh_sjlj_setjmp instructions to mark that a function
with setjmp/longjmp exception handling clobbers all the registers. But with
the recent reorganization of ARM EH, those eh_sjlj_setjmp instructions are
expanded away earlier, before PEI can see them to determine what registers to
save and restore. Mark the dispatchsetup instruction in the same way, since
that instruction cannot be expanded early. This also more accurately reflects
when the registers are clobbered.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146949 91177308-0d34-0410-b5e6-96231b3b80d8
