When the hash function uses object pointers all free entries eventually
become tombstones as they are used at least once, regardless of the size.
DenseMap cannot function with zero empty keys, so it double size to get
get ridof the tombstones.
However DenseMap never shrinks automatically unless it is cleared, so
the net result is that certain tables grow infinitely.
The solution is to make a fresh copy of the table without tombstones
instead of doubling size, by simply calling grow with the current size.
Patch by José Fonseca!
llvm-svn: 128564
The rewriter can keep track of multiple stack slots in the same register if they
happen to have the same value. When an instruction modifies a stack slot by
defining a register that is mapped to a stack slot, other stack slots in that
register are no longer valid.
This is a very rare problem, and I don't have a simple test case. I get the
impression that VirtRegRewriter knows it is about to be deleted, inventing a
last opaque problem.
<rdar://problem/9204040>
llvm-svn: 128562
The idea is, that if an ieee 754 float is divided by a power of two, we can
turn the division into a cheaper multiplication. This function sees if we can
get an exact multiplicative inverse for a divisor and returns it if possible.
This is the hard part of PR9587.
I tested many inputs against llvm-gcc's frotend implementation of this
optimization and didn't find any difference. However, floating point is the
land of weird edge cases, so any review would be appreciated.
llvm-svn: 128545
When DCE clones a live range because it separates into connected components,
make sure that the clones enter the same register allocator stage as the
register they were cloned from.
For instance, clones may be split even when they where created during spilling.
Other registers created during spilling are not candidates for splitting or even
(re-)spilling.
llvm-svn: 128524
was lowering them to sext / uxt + mul instructions. Unfortunately the
optimization passes may hoist the extensions out of the loop and separate them.
When that happens, the long multiplication instructions can be broken into
several scalar instructions, causing significant performance issue.
Note the vmla and vmls intrinsics are not added back. Frontend will codegen them
as intrinsics vmull* + add / sub. Also note the isel optimizations for catching
mul + sext / zext are not changed either.
First part of rdar://8832507, rdar://9203134
llvm-svn: 128502
- Also emit a list of packages and groups sorted by name
- Avoid iterating over DenseSet so that the output of the arrays is deterministic.
llvm-svn: 128489
unnecesary conditionals and introduced a new convenience function.
The problem was that the list of libraries for Clang's unit tests was
<clang libraries> <system libraries> <llvm libraries>. As the llvm
libraries references symbols defined on the system libraries, those
were reported as undefined.
llvm-svn: 128484
