llvm-6502/lib
Cameron Zwarich 4e7f23b1b6 Land a first cut at StrongPHIElimination. There are only 5 new test failures
when running without the verifier, and I have not yet checked them to see if
the new results are still correct. There are more verifier failures, but they
all seem to be additional occurrences of verifier failures that occur with the
existing PHIElimination pass. There are a few obvious issues with the code:

1) It doesn't properly update the register equivalence classes during copy
insertion, and instead recomputes them before merging live intervals and
renaming registers. I wanted to keep this first patch simple for debugging
purposes, but it shouldn't be very hard to do this.

2) It doesn't mix the renaming and live interval merging with the copy insertion
process, which leads to a lot of virtual register churn. Virtual registers and
live intervals are created, only to later be merged into others. The code should
be smarter and only create a new virtual register if there is no existing
register in the same congruence class.

3) In one place the code uses a DenseMap per basic block, which is unnecessary
heap allocation. There should be an inline storage version of DenseMap.

I did a quick compile-time test of running llc on 403.gcc with and without
StrongPHIElimination. It is slightly slower with StrongPHIElimination, because
the small decrease in the coalescer runtime can't beat the increase in phi
elimination runtime. Perhaps fixing the above performance issues will narrow
the gap.

I also haven't yet run any tests of the quality of the generated code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122582 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-27 10:08:19 +00:00
..
Analysis move isBytewiseValue out to ValueTracking.h/cpp 2010-12-26 20:15:01 +00:00
Archive MemoryBuffer now return an error_code and returns a OwningPtr<MemoryBuffer> via an out parm. 2010-12-16 03:29:14 +00:00
AsmParser Add missing standard headers. Patch by Joerg Sonnenberger! 2010-12-19 20:43:38 +00:00
Bitcode Add missing standard headers. Patch by Joerg Sonnenberger! 2010-12-19 20:43:38 +00:00
CodeGen Land a first cut at StrongPHIElimination. There are only 5 new test failures 2010-12-27 10:08:19 +00:00
CompilerDriver Support/PathV1: Deprecate get{Basename,Dirname,Suffix}. 2010-12-18 22:23:07 +00:00
ExecutionEngine Remove unneeded zero arrays. 2010-12-04 15:28:22 +00:00
Linker Fix whitespace. 2010-12-18 22:23:15 +00:00
MC Handle reloc_riprel_4byte_movq_load. Should make the bots happy. 2010-12-27 02:03:24 +00:00
Object Fix mismatched new[]/delete. 2010-12-17 09:56:50 +00:00
Support Support/PathV1: Deprecate GetRootDirectory. 2010-12-27 03:21:41 +00:00
Target Add support for the same encodings of the personality function that gnu as 2010-12-27 00:36:05 +00:00
Transforms BuildLibCalls: Nuke EmitMemCpy, EmitMemMove and EmitMemSet. They are dead and superseded by IRBuilder. 2010-12-27 00:25:32 +00:00
VMCore add methods to IRBuilder to create memcpy/memset/memmove. 2010-12-26 22:49:25 +00:00
Makefile Add LLVMObject Library. 2010-11-15 03:21:41 +00:00