When splitting a critical edge, the registers live through the edge are:
- Used in a PHI instruction, or
- Live out from the predecessor, and
- Live in to the successor.
This allows the coalescer to eliminate even more phi joins.
llvm-svn: 89530
DIEs are created from MDNode, which are already uniqued. And DwarfDebug already uses ValueMaps to find and use existing DIE for a given MDNode.
llvm-svn: 89518
which was an expensive checks failure due to a bug in the checking. This
patch in essence reverts the original fix for PR3393, and refixes it by a
tweak to the way expensive checking is done.
llvm-svn: 89454
critical edges in PHIElimination.
This has a huge impact on regalloc performance, and we recover almost all of
the 10% compile time regression that edge splitting introduced.
llvm-svn: 89381
Add a -linearscan-skip-count argument (default to 0) that tells the
allocator to remember the last N registers it allocated and skip them
when looking for a register candidate. This tends to spread out
register usage and free up post-allocation scheduling at the cost of
slightly more register pressure. The primary benefit is the ability
to backschedule reloads.
This is turned off by default.
llvm-svn: 89356
All spiller calls in RegAllocLinearScan now go through the new Spiller interface.
The "-new-spill-framework" command line option has been removed. To use the trivial in-place spiller you should now pass "-spiller=trivial -rewriter=trivial".
(Note the trivial spiller/rewriter are only meant to serve as examples of the new in-place modification work. Enabling them will yield terrible, though hopefully functional, code).
llvm-svn: 89311
When TwoAddressInstructionPass deletes a dead instruction, make sure that all
register kills are accounted for. The 2-addr register does not get special
treatment.
llvm-svn: 89246
when LiveVariables is available.
The -split-phi-edges is now gone, and so is the hack to disable it when using
the local register allocator. The PHIElimination pass no longer has
LiveVariables as a prerequisite - that is what broke the local allocator.
Instead we do critical edge splitting when possible - that is when
LiveVariables is available.
llvm-svn: 89213
contents of the block to be duplicated. Use this for ARM Cortex A8/9 to
be more aggressive tail duplicating indirect branches, since it makes it
much more likely that they will be predicted in the branch target buffer.
Testcase coming soon.
llvm-svn: 89187
The local register allocator doesn't like it when LiveVariables is run.
We should also disable edge splitting under -O0, but that has to wait a bit.
llvm-svn: 89125
unnecessary. It is broken because the "isIdenticalTo" check should be
negated. If that is fixed, this code causes the CodeGen/X86/tail-opts.ll
test to fail, in the dont_merge_oddly function. And, I confirmed that the
regression is real -- the generated code is worse. As far as I can tell,
that tail-opts.ll test is checking for what this code is supposed to handle
and we're doing the right thing anyway.
llvm-svn: 89121
