Added asserts whenever attempting to use a potentially
uninitialized pass. This helps people trying to develop a new pass and
people trying to understand the bug reports filed by the former people.
llvm-svn: 132520
When compiling a program with lots of small functions like
483.xalancbmk, this makes RAFast 11% faster.
Add some comments to clarify the difference between unallocatable and
reserved registers. It's quite subtle.
The fast register allocator depends on EFLAGS' not being allocatable on
x86. That way it can completely avoid tracking liveness, and it won't
mind when there are multiple uses of a single def.
llvm-svn: 132514
Some register classes are only used for instruction operand constraints.
They should never be used for virtual registers. Previously, those
register classes were given an empty allocation order, but now you can
say 'let isAllocatable=0' in the register class definition.
TableGen calculates if a register is part of any allocatable register
class, and makes that information available in TargetRegisterDesc::inAllocatableClass.
The goal here is to eliminate use cases for overriding allocation_order_*
methods.
llvm-svn: 132508
I was confused whether new uint8_t[] would zero-initialize the returned
array, and it seems that so is gcc-4.0.
This should fix the test failures on darwin 9.
llvm-svn: 132500
Instead, use simpler approach and let DBG_VALUE follow its predecessor instruction. After live debug value analysis pass, all DBG_VALUE instruction are placed at the right place. Thanks Jakob for the hint!
llvm-svn: 132483
Parsing a register name/number for .cfi directives can't assume that a
register name starts with a '%' token. Be more flexible and check for a
register number instead. Still unlikely to be perfect, but it allows us
to parse both plain identifiers as register names and integers as register
numbers, which is what we're wanting to support at this point.
llvm-svn: 132466
register classes.
It provides information for each register class that cannot be
determined statically, like:
- The number of allocatable registers in a class after filtering out the
reserved and invalid registers.
- The preferred allocation order with registers that overlap callee-saved
registers last.
- The last callee-saved register that overlaps a given physical register.
This information usually doesn't change between functions, so it is
reused for compiling multiple functions when possible. The many
possible combinations of reserved and callee saves registers makes it
unfeasible to compute this information statically in TableGen.
Use RegisterClassInfo to count available registers in various heuristics
in SimpleRegisterCoalescing, making the pass run 4% faster.
llvm-svn: 132450
In the given testcase, the "Clobber" was pointing to a load, and GVN was incorrectly assuming that meant that the "Clobber" load overlapped the load being analyzed (when they are actually unrelated).
The included testcase tests both this commit and r132434.
Part two of rdar://9429882. (r132434 was mislabeled.)
llvm-svn: 132442
