Inline a function when the always_inline attribute

is set even when it contains a indirect branch.
The attribute overrules correctness concerns
like the escape of a local block address.

This is for rdar://16501761




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206429 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 2 deletions

diff --git a/lib/Analysis/IPA/InlineCost.cpp b/lib/Analysis/IPA/InlineCost.cpp
index a803f8c3bf..683637f5b7 100644
--- a/lib/Analysis/IPA/InlineCost.cpp
+++ b/lib/Analysis/IPA/InlineCost.cpp
@@ -1300,8 +1300,14 @@ bool InlineCostAnalysis::isInlineViable(Function &F) {
     F.getAttributes().hasAttribute(AttributeSet::FunctionIndex,
                                    Attribute::ReturnsTwice);
   for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
-    // Disallow inlining of functions which contain an indirect branch.
-    if (isa<IndirectBrInst>(BI->getTerminator()))
+    // Disallow inlining of functions which contain an indirect branch,
+    // unless the always_inline attribute is set.
+    // The attribute serves as a assertion that no local address
+    // like a block label can escpape the function.
+    // Revisit enabling inlining for functions with indirect branches
+    // when a more sophisticated espape/points-to analysis becomes available.
+    if (isa<IndirectBrInst>(BI->getTerminator()) &&
+        !F.hasFnAttribute(Attribute::AlwaysInline))
       return false;
 
     for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE;