Commit Graph

23 Commits

Author SHA1 Message Date
Evan Cheng
3115698611 Rewrite machine cse to avoid recursion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101964 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-21 00:21:07 +00:00
Evan Cheng
d6060a4ce9 Typo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101914 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-20 17:27:38 +00:00
Evan Cheng
db8771af28 After trivial coalescing, the MI being visited may have become a copy. Avoid adding it to CSE hash table since copies aren't being considered for CSE and they may be deleted.
rdar://7819990


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100170 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-02 02:21:24 +00:00
Evan Cheng
2250425d6e dbg_value may end a block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99378 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-24 01:50:28 +00:00
Evan Cheng
112e5e7eff Code clean up.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99319 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-23 20:33:48 +00:00
Dale Johannesen
e68ea060c7 Fix debug_value handling.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98224 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-11 02:10:24 +00:00
Evan Cheng
2938a00f29 Add a couple more heuristics to neuter machine cse some more.
1. Be careful with cse "cheap" expressions. e.g. constant materialization. Only cse them when the common expression is local or in a direct predecessor. We don't want cse of cheap instruction causing other expressions to be spilled.
2. Watch out for the case where the expression doesn't itself uses a virtual register. e.g. lea of frame object. If the common expression itself is used by copies (common for passing addresses to function calls), don't perform the cse. Since these expressions do not use a register, it creates a live range but doesn't close any, we want to be very careful with increasing register pressure.

Note these are heuristics so machine cse doesn't make register allocator unhappy. Once we have proper live range splitting and re-materialization support in place, these should be evaluated again.

Now machine cse is almost always a win on llvm nightly tests on x86 and x86_64.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98121 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-10 02:12:03 +00:00
Evan Cheng
bfc9999563 Allow more cross-rc coalescing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98048 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-09 06:38:17 +00:00
Jakob Stoklund Olesen
1552cccc76 Don't do illegal cross-class coalescing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98044 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-09 03:56:06 +00:00
Evan Cheng
31f94c7c22 - Make the machine cse dumb coalescer (as opposed to the more awesome simple
coalescer) handle sub-register classes.
- Add heuristics to avoid non-profitable cse. Given the current lack of live
  range splitting, avoid cse when an expression has PHI use and the would be
  new use is in a BB where the expression wasn't already being used.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98043 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-09 03:21:12 +00:00
Evan Cheng
5196018d9c Don't waste time trying to CSE labels, phis, inline asm. Definitely avoid cse implicit-def for obvious performance reason.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98009 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-08 23:49:12 +00:00
Evan Cheng
6c3b8ac6c9 Restrict machine cse to really trivial coalescing. Leave the heavy lifting to a real coalescer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98007 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-08 23:28:08 +00:00
Evan Cheng
6cc1aeaad2 Don't update physical register def.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97861 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-06 01:14:19 +00:00
Evan Cheng
a5f32cb3d3 Avoid cse load instructions unless they are known to be invariant loads.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97747 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-04 21:18:08 +00:00
Evan Cheng
b3958e8032 Look ahead a bit to determine if a physical register def that is not marked dead is really alive. This is necessary to catch a lot of common cse opportunities for targets like x86.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97706 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-04 01:33:55 +00:00
Evan Cheng
67bda7215b Fix a logic error. An instruction that has a live physical register def cannot be CSE'ed, but it *can* be used to replace a common subexpression.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97688 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03 23:59:08 +00:00
Evan Cheng
05bdcbb1ae Re-apply r97667 but with a little bit of thought put into the patch. This implements a special DenseMapInfo trait for DenseMap<MachineInstr*> that compare the value of the MachineInstr rather than the pointer value. Since the hashing and equality test functions ignore defs it's useful for doing CSE kind optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97678 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03 23:27:36 +00:00
Dan Gohman
319dfa3fb3 Revert 97667. It broke a bunch of tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97673 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03 22:40:03 +00:00
Evan Cheng
a054ae02fd Move DenseMapInfo for MachineInstr* to MachineInstr.h
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97667 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03 21:47:16 +00:00
Evan Cheng
16b48b8a05 Machine CSE work in progress. It's doing some CSE now. But implicit def of physical registers are getting in the way.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97664 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03 21:20:05 +00:00
Evan Cheng
6ba9554988 Work in progress. Finding some cse now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97635 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03 02:48:20 +00:00
Evan Cheng
c5bbba1e49 Fix typo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97577 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-02 19:02:27 +00:00
Evan Cheng
c6fe333688 Add skeleton of a machine level cse pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97543 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-02 02:38:24 +00:00