Commit Graph

17 Commits

Author SHA1 Message Date
Dan Gohman
f52038a204 Delete unnecessary elses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63214 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-28 18:03:09 +00:00
Dan Gohman
33a9cb4f40 Make ISel ignore dead nodes. The DAGCombiner normally eliminates
dead nodes, but in this case its missing one. Fixing the DAGCombiner
is desirable, but it's somewhat involved.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58777 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-05 22:56:47 +00:00
Dan Gohman
fbcb52afdf The HadDelete field is no longer used.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58761 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-05 17:35:14 +00:00
Dan Gohman
695ea6e57e Update some comments to reflect the new code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58759 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-05 17:13:57 +00:00
Dan Gohman
8be6bbe5bf Eliminate the ISel priority queue, which used the topological order for a
priority function. Instead, just iterate over the AllNodes list, which is
already in topological order. This eliminates a fair amount of bookkeeping,
and speeds up the isel phase by about 15% on many testcases.

The impact on most targets is that AddToISelQueue calls can be simply removed.

In the x86 target, there are two additional notable changes.

The rule-bending AND+SHIFT optimization in MatchAddress that creates new
pre-isel nodes during isel is now a little more verbose, but more robust.
Instead of either creating an invalid DAG or creating an invalid topological
sort, as it has historically done, it can now just insert the new nodes into
the node list at a position where they will be consistent with the topological
ordering.

Also, the address-matching code has logic that checked to see if a node was
"already selected". However, when a node is selected, it has all its uses
taken away via ReplaceAllUsesWith or equivalent, so it won't recieve any
further visits from MatchAddress. This code is now removed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58748 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-05 04:14:16 +00:00
Dan Gohman
00b58dfc88 Totally disable the setSubgraphColor calls temporarily, as they're
currently troublesome even for #ifndef NDEBUG builds.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58512 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-31 16:12:56 +00:00
Dan Gohman
f4717aa1b2 Add some more information to the top-level comment for this file.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58339 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-28 18:47:37 +00:00
Evan Cheng
83f5c856d9 Avoid calls to setSubgraphColor in release mode. They generate lots of error messages and slow down compilation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58336 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-28 17:23:13 +00:00
David Greene
8ad4c00c00 Have TableGen emit setSubgraphColor calls under control of a -gen-debug
flag.  Then in a debugger developers can set breakpoints at these calls
to see waht is about to be selected and what the resulting subgraph
looks like.  This really helps when debugging instruction selection.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58278 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-27 21:56:29 +00:00
Dan Gohman
f06c835f76 Optimize SelectionDAG's AssignTopologicalOrder even further.
Completely eliminate the TopOrder std::vector. Instead, sort
the AllNodes list in place. This also eliminates the need to
call AllNodes.size(), a linear-time operation, before
performing the sort.

Also, eliminate the Sources temporary std::vector, since it
essentially duplicates the sorted result as it is being
built.

This also changes the direction of the topological sort
from bottom-up to top-down. The AllNodes list starts out in
roughly top-down order, so this reduces the amount of
reordering needed. Top-down is also more convenient for
Legalize, and ISel needed only minor adjustments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56867 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-30 18:30:35 +00:00
Gabor Greif
ba36cb5242 erect abstraction boundaries for accessing SDValue members, rename Val -> Node to reflect semantics
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55504 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-28 21:40:38 +00:00
Dan Gohman
ad3460c3c9 Simplify SelectRoot's interface, and factor out some common code
from all targets.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55124 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-21 16:36:34 +00:00
Dan Gohman
475871a144 Rename SDOperand to SDValue.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54128 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-27 21:46:04 +00:00
Dan Gohman
e8be6c6391 Add a new function, ReplaceAllUsesOfValuesWith, which handles bulk
replacement of multiple values. This is slightly more efficient
than doing multiple ReplaceAllUsesOfValueWith calls, and theoretically
could be optimized even further. However, an important property of this
new function is that it handles the case where the source value set and
destination value set overlap. This makes it feasible for isel to use
SelectNodeTo in many very common cases, which is advantageous because
SelectNodeTo avoids a temporary node and it doesn't require CSEMap
updates for users of values that don't change position.

Revamp MorphNodeTo, which is what does all the work of SelectNodeTo, to
handle operand lists more efficiently, and to correctly handle a number
of corner cases to which its new wider use exposes it.

This commit also includes a change to the encoding of post-isel opcodes
in SDNodes; now instead of being sandwiched between the target-independent
pre-isel opcodes and the target-dependent pre-isel opcodes, post-isel
opcodes are now represented as negative values. This makes it possible
to test if an opcode is pre-isel or post-isel without having to know
the size of the current target's post-isel instruction set.

These changes speed up llc overall by 3% and reduce memory usage by 10%
on the InstructionCombining.cpp testcase with -fast and -regalloc=local.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53728 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-17 19:10:17 +00:00
Evan Cheng
79d99b8b14 Indentation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53727 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-17 18:41:20 +00:00
Duncan Sands
edfcf598fa Sometimes (rarely) nodes held in LegalizeTypes
maps can be deleted.  This happens when RAUW
replaces a node N with another equivalent node
E, deleting the first node.  Solve this by
adding (N, E) to ReplacedNodes, which is already
used to remap nodes to replacements.  This means
that deleted nodes are being allowed in maps,
which can be delicate: the memory may be reused
for a new node which might get confused with the
old deleted node pointer hanging around in the
maps, so detect this and flush out maps if it
occurs (ExpungeNode).  The expunging operation
is expensive, however it never occurs during
a llvm-gcc bootstrap or anywhere in the nightly
testsuite.  It occurs three times in "make check":
Alpha/illegal-element-type.ll,
PowerPC/illegal-element-type.ll and
X86/mmx-shift.ll.  If expunging proves to be too
expensive then there are other more complicated
ways of solving the problem.
In the normal case this patch adds the overhead
of a few more map lookups, which is hopefully
negligable.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52214 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-11 11:42:12 +00:00
Roman Levenstein
6422e8aa1c Do not generate by TableGen the hard-coded standard, target-independent part of
DAG instruction selectors. Introudce a dedicated header file for this part:
include/llvm/CodeGen/DAGISelHeader.h

TableGen now only generates the include preprocessor directive to include this
new header.

This is a preparation for supporting multiple implementations of instruction
selectors in the future.

Reviewed and approved by Evan and Dan.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51102 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-14 10:17:11 +00:00