This transformation will transform a conditional store with a preceeding
uncondtional store to the same location:
a[i] =
may-alias with a[i] load
if (cond)
a[i] = Y
into an unconditional store.
a[i] = X
may-alias with a[i] load
tmp = cond ? Y : X;
a[i] = tmp
We assume that on average the cost of a mispredicted branch is going to be
higher than the cost of a second store to the same location, and that the
secondary benefits of creating a bigger basic block for other optimizations to
work on outway the potential case were the branch would be correctly predicted
and the cost of the executing the second store would be noticably reflected in
performance.
hmmer's execution time improves by 30% on an imac12,2 on ref data sets. With
this change we are on par with gcc's performance (gcc also performs this
transformation). There was a 1.2 % performance improvement on a ARM swift chip.
Other tests in the test-suite+external seem to be mostly uninfluenced in my
experiments:
This optimization was triggered on 41 tests such that the executable was
different before/after the patch. Only 1 out of the 40 tests (dealII) was
reproducable below 100% (by about .4%). Given that hmmer benefits so much I
believe this to be a fair trade off.
I am going to watch performance numbers across the builtbots and will revert
this if anything unexpected comes up.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179957 91177308-0d34-0410-b5e6-96231b3b80d8
Previously, when spilling 64-bit paired registers, an LDMIA with both
a FrameIndex and an offset was produced. This kind of instruction
shouldn't exist, and the extra operand was being confused with the
predicate, causing aborts later on.
This removes the invalid 0-offset from the instruction being
produced.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179956 91177308-0d34-0410-b5e6-96231b3b80d8
I think it's almost impossible to fold atomic fences profitably under
LLVM/C++11 semantics. As a result, this is now unused and just
cluttering up the target interface.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179940 91177308-0d34-0410-b5e6-96231b3b80d8
This is part of a future patch to use yamlio that incorrectly ended up in a
cleanup patch.
Thanks to Benjamin Kramer for reporting it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179938 91177308-0d34-0410-b5e6-96231b3b80d8
The getSwappedPredicate function can be used in other places (such as in
improvements to the PPCCTRLoops pass). Instead of trapping it as a static
function in PPCInstrInfo, move it into PPCPredicates with other
predicate-related things.
No functionality change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179926 91177308-0d34-0410-b5e6-96231b3b80d8
Instead, use MappingNormalization to directly parse COFF::header. Also change
the naming convention of the helper classes to be a bit shorter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179917 91177308-0d34-0410-b5e6-96231b3b80d8
The logic that actually compares the types considers pointers and integers the
same if they are of the same size. This created a strange mismatch between hash
and reality and made the test case for this fail on some platforms (yay,
test cases).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179905 91177308-0d34-0410-b5e6-96231b3b80d8
trying to move as much FastISel logic as possible out of the main path in
SelectionDAGISel - intermixing them just adds confusion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179902 91177308-0d34-0410-b5e6-96231b3b80d8
When matching a compare with a subtract where the arguments of the compare are
swapped w.r.t. the arguments of the subtract, we need to negate the predicates
(or CR bit indices) of the users. This, however, is not the same as inverting
the predicate (negating LT -> GT, but inverting LT -> GE, for example). The ARM
backend seems to do this correctly, but when I adapted the code for the PPC
backend, I introduced an error in this logic.
Comparison optimization is now enabled again by default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179899 91177308-0d34-0410-b5e6-96231b3b80d8
Also make some static function class functions to avoid having to mention the
class namespace for enums all the time.
No functionality change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179886 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds support for recoded (meaning assembly-language compatible to
standard mips32) arithmetic 32-bit instructions.
Patch by Zoran Jovanovic.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179873 91177308-0d34-0410-b5e6-96231b3b80d8
