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| author | Owen Anderson <resistor@mac.com> | 2010-09-21 18:41:19 +0000 |
|---|---|---|
| committer | Owen Anderson <resistor@mac.com> | 2010-09-21 18:41:19 +0000 |
| commit | c004eec71b49ae13ee4d9f859c61cdb9ed092b22 (patch) | |
| tree | 23a74efbf817f08bb796242ade0c68d03bf68c17 /lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | |
| parent | 89bfef003ec71792d078d489566655006b89bc43 (diff) | |
| download | external_llvm-c004eec71b49ae13ee4d9f859c61cdb9ed092b22.zip external_llvm-c004eec71b49ae13ee4d9f859c61cdb9ed092b22.tar.gz external_llvm-c004eec71b49ae13ee4d9f859c61cdb9ed092b22.tar.bz2 | |
When adding the carry bit to another value on X86, exploit the fact that the carry-materialization
(sbbl x, x) sets the registers to 0 or ~0. Combined with two's complement arithmetic, we can fold
the intermediate AND and the ADD into a single SUB.
This fixes <rdar://problem/8449754>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114460 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/LegalizeDAG.cpp')
0 files changed, 0 insertions, 0 deletions