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| author | James Molloy <james.molloy@arm.com> | 2012-12-20 16:04:27 +0000 |
|---|---|---|
| committer | James Molloy <james.molloy@arm.com> | 2012-12-20 16:04:27 +0000 |
| commit | 67ae13575900e8efd056672987249fd0adbf5e73 (patch) | |
| tree | c297968f698f92b4b2d7b06c6d892a2299061887 /docs | |
| parent | 6af228a92a7b8414fa3c1b3c37ee659d32e66e1b (diff) | |
| download | llvm-67ae13575900e8efd056672987249fd0adbf5e73.tar.gz llvm-67ae13575900e8efd056672987249fd0adbf5e73.tar.bz2 llvm-67ae13575900e8efd056672987249fd0adbf5e73.tar.xz | |
Add a new attribute, 'noduplicate'. If a function contains a noduplicate call, the call cannot be duplicated - Jump threading, loop unrolling, loop unswitching, and loop rotation are inhibited if they would duplicate the call.
Similarly inlining of the function is inhibited, if that would duplicate the call (in particular inlining is still allowed when there is only one callsite and the function has internal linkage).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170704 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/LangRef.rst | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/docs/LangRef.rst b/docs/LangRef.rst index 1ea475dee6..3c49ed0a87 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -845,6 +845,17 @@ example: show that no exceptions passes by it. This is normally the case for the ELF x86-64 abi, but it can be disabled for some compilation units. +``noduplicate`` + This attribute indicates that calls to the function cannot be + duplicated. A call to a ``noduplicate`` function may be moved + within its parent function, but may not be duplicated within + its parent function. + + A function containing a ``noduplicate`` call may still + be an inlining candidate, provided that the call is not + duplicated by inlining. That implies that the function has + internal linkage and only has one call site, so the original + call is dead after inlining. .. _moduleasm: |