replaced by a bigger array in SmallPtrSet (by overridding it), instead just use a
pointer to the start of the storage, and have SmallPtrSet pass in the value to use.
This has the disadvantage that SmallPtrSet becomes bigger by one pointer. It has
the advantage that it no longer uses tricky C++ rules, and is clearly correct while
I'm not sure the previous version was. This was inspired by g++-4.6 pointing out
that SmallPtrSetImpl was writing off the end of SmallArray, which it was. Since
SmallArray is replaced with a bigger array in SmallPtrSet, the write was still to
valid memory. But it was writing off the end of the declared array type - sounds
kind of dubious to me, like it sounded dubious to g++-4.6. Maybe g++-4.6 is wrong
and this construct is perfectly valid and correctly compiled by all compilers, but
I think it is better to avoid the whole can of worms by avoiding this construct.
llvm-svn: 107285
SmallArray[SmallSize] in the SmallPtrSetIteratorImpl, and this is
one off the end of the array. For those who care, right now gcc
warns about writing off the end because it is confused about the
declaration of SmallArray as having length 1 in the parent class
SmallPtrSetIteratorImpl. However if you tweak code to unconfuse
it, then it still warns about writing off the end of the array,
because of this buffer overflow. In short, even with this fix
gcc-4.6 will warn about writing off the end of the array, but now
that is only because it is confused.
llvm-svn: 107200
the Profile method. Currently this only works with the default FoldingSetTraits
implementation.
The point of this is to allow nodes to not store context values which are only
used during profiling. A better solution would thread this value through the
folding algorithms, but then those would need to be (1) templated and
(2) non-opaque.
llvm-svn: 105819
'class llvm::DAGDeltaAlgorithm' has virtual functions and accessible non-virtual destructor
Not sure if this is the best solution, but this class has state and some of the
classes that inherit from it also do, so it looks appropriate.
llvm-svn: 105675
- This provides a convenient alternative to using something llvm::prior or
manual iterator access, for example::
if (T *Prev = foo->getPrevNode())
...
instead of::
iterator it(foo);
if (it != begin()) {
--it;
...
}
- Chris, please review.
llvm-svn: 103647
Microoptimize Twine's with unsigned and int to not pin their value to
the stack. This saves stack space in common cases and allows mem2reg
in the caller. A simple example is:
void foo(const Twine &);
void bar(int x) {
foo("xyz: " + Twine(x));
}
Before:
__Z3bari:
subq $40, %rsp
movl %edi, 36(%rsp)
leaq L_.str3(%rip), %rax
leaq 36(%rsp), %rcx
leaq 8(%rsp), %rdi
movq %rax, 8(%rsp)
movq %rcx, 16(%rsp)
movb $3, 24(%rsp)
movb $7, 25(%rsp)
callq __Z3fooRKN4llvm5TwineE
addq $40, %rsp
ret
After:
__Z3bari:
subq $24, %rsp
leaq L_.str3(%rip), %rax
movq %rax, (%rsp)
movslq %edi, %rax
movq %rax, 8(%rsp)
movb $3, 16(%rsp)
movb $7, 17(%rsp)
leaq (%rsp), %rdi
callq __Z3fooRKN4llvm5TwineE
addq $24, %rsp
ret
It saves 16 bytes of stack and one instruction in this case.
llvm-svn: 103107
Limit alignment in SmallVector 8, otherwise GCC assumes 16 byte alignment.
opetaror new, and malloc only return 8-byte aligned memory on 32-bit Linux,
which cause a crash if code is compiled with -O3 (or -ftree-vectorize) and some
SmallVector code is vectorized.
llvm-svn: 102604
CGSCC can delete nodes in regions of the callgraph that
have already been visited. If new CG nodes are allocated
to the same pointer, we shouldn't abort, just handle it
correctly by assigning a new number. This should restore
stability by removing invalidated pointers that *will* be
reused from the densemap in the iterator.
llvm-svn: 101628
to keep the node entries in scc_iterator up to date instead of dangling as
the SCC mutates.
This is a really terrible problem which was causing -g to affect codegen
because it would permute the memory image of the compiler process.
Thanks to Dale for expertly hunting it down.
llvm-svn: 101565
ownership over the pointer it contains. Useful when we want to
communicate ownership while still having several clients holding on to
the same pointer *without* introducing reference counting.
llvm-svn: 100463
