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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2011-04-04 21:00:03 +0000 |
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| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2011-04-04 21:00:03 +0000 |
| commit | 4662a9f270fe2c916c35545718720ed181384c30 (patch) | |
| tree | 331cf4d4d3f80cbba0e2473652746b2b27d10ee7 /tools | |
| parent | 0c1953d8cf02edfae896b0a983d345ad61b13b9f (diff) | |
| download | llvm-4662a9f270fe2c916c35545718720ed181384c30.tar.gz llvm-4662a9f270fe2c916c35545718720ed181384c30.tar.bz2 llvm-4662a9f270fe2c916c35545718720ed181384c30.tar.xz | |
Allow coalescing with reserved physregs in certain cases:
When a virtual register has a single value that is defined as a copy of a
reserved register, permit that copy to be joined. These virtual register are
usually copies of the stack pointer:
%vreg75<def> = COPY %ESP; GR32:%vreg75
MOV32mr %vreg75, 1, %noreg, 0, %noreg, %vreg74<kill>
MOV32mi %vreg75, 1, %noreg, 8, %noreg, 0
MOV32mi %vreg75<kill>, 1, %noreg, 4, %noreg, 0
CALLpcrel32 ...
Coalescing these virtual registers early decreases register pressure.
Previously, they were coalesced by RALinScan::attemptTrivialCoalescing after
register allocation was completed.
The lower register pressure causes the mcinst-lowering-cmp0.ll test case to fail
because it depends on linear scan spilling a particular register.
I am deleting 2008-08-05-SpillerBug.ll because it is counting the number of
instructions emitted, and its revision history shows the 'correct' count being
edited many times.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128845 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'tools')
0 files changed, 0 insertions, 0 deletions