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

1 files changed, 6 insertions, 3 deletions

diff --git a/include/llvm/Analysis/CodeMetrics.h b/include/llvm/Analysis/CodeMetrics.h
index 4398faa20a..35eabec6ee 100644
--- a/include/llvm/Analysis/CodeMetrics.h
+++ b/include/llvm/Analysis/CodeMetrics.h
@@ -46,8 +46,11 @@ namespace llvm {
     /// \brief True if this function calls itself.
     bool isRecursive;
 
-    /// \brief True if this function contains one or more indirect branches.
-    bool containsIndirectBr;
+    /// \brief True if this function cannot be duplicated.
+    ///
+    /// True if this function contains one or more indirect branches, or it contains
+    /// one or more 'noduplicate' instructions.
+    bool notDuplicatable;
 
     /// \brief True if this function calls alloca (in the C sense).
     bool usesDynamicAlloca;
@@ -79,7 +82,7 @@ namespace llvm {
     unsigned NumRets;
 
     CodeMetrics() : exposesReturnsTwice(false), isRecursive(false),
-                    containsIndirectBr(false), usesDynamicAlloca(false),
+                    notDuplicatable(false), usesDynamicAlloca(false),
                     NumInsts(0), NumBlocks(0), NumCalls(0),
                     NumInlineCandidates(0), NumVectorInsts(0),
                     NumRets(0) {}