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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2011-09-01 18:27:51 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2011-09-01 18:27:51 +0000 |
| commit | 4a0a18af4a9a47466a6077a158387ba4f57bf636 (patch) | |
| tree | c147d444f5f533499a7252ed62065e83b92fbd01 /lib/MC/MCDisassembler/EDDisassembler.cpp | |
| parent | 2f25d9b9334662e846460e98a8fe2dae4f233068 (diff) | |
Permit remat of partial register defs when it is safe.
An instruction may define part of a register where the other bits are
undefined. In that case, it is safe to rematerialize the instruction.
For example:
%vreg2:ssub_0<def> = VLDRS <cp#0>, 0, pred:14, pred:%noreg, %vreg2<imp-def>
The extra <imp-def> operand indicates that the instruction does not read
the other parts of the virtual register, so a remat is safe.
This patch simply allows multiple def operands for the virtual register.
It is MI->readsVirtualRegister() that determines if we depend on a
previous value so remat is impossible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138953 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/MC/MCDisassembler/EDDisassembler.cpp')
0 files changed, 0 insertions, 0 deletions