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
diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp
index 1457bea..d88f8a8 100644
--- a/lib/Analysis/LoopInfo.cpp
+++ b/lib/Analysis/LoopInfo.cpp
@@ -213,10 +213,22 @@
/// isSafeToClone - Return true if the loop body is safe to clone in practice.
/// Routines that reform the loop CFG and split edges often fail on indirectbr.
bool Loop::isSafeToClone() const {
- // Return false if any loop blocks contain indirectbrs.
+ // Return false if any loop blocks contain indirectbrs, or there are any calls
+ // to noduplicate functions.
for (Loop::block_iterator I = block_begin(), E = block_end(); I != E; ++I) {
- if (isa<IndirectBrInst>((*I)->getTerminator()))
+ if (isa<IndirectBrInst>((*I)->getTerminator())) {
return false;
+ } else if (const InvokeInst *II = dyn_cast<InvokeInst>((*I)->getTerminator())) {
+ if (II->hasFnAttr(Attribute::NoDuplicate))
+ return false;
+ }
+
+ for (BasicBlock::iterator BI = (*I)->begin(), BE = (*I)->end(); BI != BE; ++BI) {
+ if (const CallInst *CI = dyn_cast<CallInst>(BI)) {
+ if (CI->hasFnAttr(Attribute::NoDuplicate))
+ return false;
+ }
+ }
}
return true;
}