Commit Graph

65 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen 543bef6ead Track register ages more accurately.
Keep track of the last instruction to define each register individually
instead of per DomainValue.  This lets us track more accurately when a
register was last written.

Also track register ages across basic blocks.  When entering a new
basic block, use the least stale predecessor def as a worst case
estimate for register age.

The register age is used to arbitrate between conflicting domains. The
most recently defined register wins.

llvm-svn: 144601
2011-11-15 01:15:25 +00:00
Jakob Stoklund Olesen 3dc89c9768 Collapse DomainValues across loop back-edges.
During the initial RPO traversal of the basic blocks, remember the ones
that are incomplete because of back-edges from predecessors that haven't
been visited yet.

After the initial RPO, revisit all those loop headers so the incoming
DomainValues on the back-edges can be properly collapsed.

This will properly fix execution domains on software pipelined code,
like the included test case.

llvm-svn: 144151
2011-11-09 01:06:56 +00:00
Jakob Stoklund Olesen 53ec977cd2 Link to the live DomainValue after merging.
When merging two uncollapsed DomainValues, place a link to the active
DomainValue from the passive DomainValue.  This allows old stale
references to the passive DomainValue to be updated to point to the
active DomainValue.

The new resolve() function finds the active DomainValue and updates the
pointer.

This change makes old live-out lists more useful since they may contain
uncollapsed DomainValues that have since been merged into other
DomainValues.

llvm-svn: 144149
2011-11-09 00:06:18 +00:00
Jakob Stoklund Olesen b7e44a3f5f Track reference count independently from clear().
This allows clear() to be called on a DomainValue with references.

llvm-svn: 144147
2011-11-08 23:26:00 +00:00
Jakob Stoklund Olesen 5d08293999 Call release() directly when cleaning up the remaining DomainValues.
There is no need to involve the LiveRegs array and kill() any longer.

llvm-svn: 144133
2011-11-08 22:05:17 +00:00
Jakob Stoklund Olesen 9e338bb0f3 Rename all methods to follow style guide.
No functional change.

llvm-svn: 144132
2011-11-08 21:57:47 +00:00
Jakob Stoklund Olesen 1438e191bd Handle reference counts in one function: release().
This new function will decrement the reference count, and collapse a
domain value when the last reference is gone.

This simplifies DomainValue reference counting, and decouples it from
the LiveRegs array.

llvm-svn: 144131
2011-11-08 21:57:44 +00:00
Jakob Stoklund Olesen 1205881820 Clear old DomainValue after merging.
The old value may still be referenced by some live-out list, and we
don't wan't to collapse those instructions twice.

This fixes the "Can only swizzle VMOVD" assertion in some armv7 SPEC
builds.

<rdar://problem/10413292>

llvm-svn: 144117
2011-11-08 20:57:04 +00:00
Jakob Stoklund Olesen a70e9417fb Kill and collapse outstanding DomainValues.
DomainValues that are only used by "don't care" instructions are now
collapsed to the first possible execution domain after all basic blocks
have been processed.  This typically means the PS domain on x86.

For example, the vsel_i64 and vsel_double functions in sse2-blend.ll are
completely collapsed to the PS domain instead of containing a mix of
execution domains created by isel.

llvm-svn: 144037
2011-11-07 23:08:21 +00:00
Jakob Stoklund Olesen 68e197e151 Use a reverse post order instead of a DFS order.
The enterBasicBlock() function is combining live-out values from
predecessor blocks.  The RPO traversal means that more predecessors
have been visited when that happens, only back-edges are missing.

llvm-svn: 144025
2011-11-07 21:59:29 +00:00
Jakob Stoklund Olesen 736cf46c3e Extract two methods. No functional change.
llvm-svn: 144020
2011-11-07 21:40:27 +00:00
Jakob Stoklund Olesen 44dcc589b3 MBB doesn't need to be a class member.
llvm-svn: 144015
2011-11-07 21:23:42 +00:00
Jakob Stoklund Olesen baffa7d35d Fix pass name after the source was moved.
llvm-svn: 144014
2011-11-07 21:23:39 +00:00
Jakob Stoklund Olesen bd5109f14d Rename class and clean up source.
No functional change intended.

llvm-svn: 140664
2011-09-28 00:01:56 +00:00
Jakob Stoklund Olesen 934b7d7645 Rename SSEDomainFix -> lib/CodeGen/ExecutionDepsFix.
I'll clean up the source in the next commit.

llvm-svn: 140663
2011-09-28 00:01:54 +00:00