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| author | Hal Finkel <hfinkel@anl.gov> | 2013-03-26 18:56:54 +0000 |
|---|---|---|
| committer | Hal Finkel <hfinkel@anl.gov> | 2013-03-26 18:56:54 +0000 |
| commit | 8846129f6eb58982a2cac22306c8c9b586084475 (patch) | |
| tree | bd24c433fd6347a3238caebe8f4636ed48b80725 /lib/Support/Program.cpp | |
| parent | b4f60e9f772de7152a0880d84c5ef511f6d2c642 (diff) | |
Update PEI's virtual-register-based scavenging to support multiple simultaneous mappings
The previous algorithm could not deal properly with scavenging multiple virtual
registers because it kept only one live virtual -> physical mapping (and
iterated through operands in order). Now we don't maintain a current mapping,
but rather use replaceRegWith to completely remove the virtual register as
soon as the mapping is established.
In order to allow the register scavenger to return a physical register killed
by an instruction for definition by that same instruction, we now call
RS->forward(I) prior to eliminating virtual registers defined in I. This
requires a minor update to forward to ignore virtual registers.
These new features will be tested in forthcoming commits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178058 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Support/Program.cpp')
0 files changed, 0 insertions, 0 deletions