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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 | 5dc87d0f4d631b6701471649c0abc7045be8d5cd (patch) | |
| tree | c2b80f2022c228e2d4d8d1da8dbb11f4fb5faa17 /clang/lib/CodeGen/ModuleBuilder.cpp | |
| parent | f6d5d60f993df484ff6bb613a90c1a69786873f3 (diff) | |
| download | llvm-5dc87d0f4d631b6701471649c0abc7045be8d5cd.zip llvm-5dc87d0f4d631b6701471649c0abc7045be8d5cd.tar.gz llvm-5dc87d0f4d631b6701471649c0abc7045be8d5cd.tar.bz2 | |
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.
llvm-svn: 138953
Diffstat (limited to 'clang/lib/CodeGen/ModuleBuilder.cpp')
0 files changed, 0 insertions, 0 deletions