patch for functions with indirect calls and always_inline attribute

[Gerolf Hoflehner]

Hi

llvm currently does not inline functions with indirect branches. We had some internal discussion and think the always_inline attribute should overrule that restriction. 

Gerolf


 

Index: lib/Analysis/IPA/InlineCost.cpp
===================================================================
--- lib/Analysis/IPA/InlineCost.cpp     (revision 206204)
+++ lib/Analysis/IPA/InlineCost.cpp     (working copy)
@@ -1301,7 +1301,8 @@
                                    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()))
+    if (isa<IndirectBrInst>(BI->getTerminator()) &&
+        !F.hasFnAttribute(Attribute::AlwaysInline))
       return false;
 
     for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE;
Index: test/Transforms/Inline/always-inline-attribute.ll
===================================================================
--- test/Transforms/Inline/always-inline-attribute.ll   (revision 0)
+++ test/Transforms/Inline/always-inline-attribute.ll   (working copy)
@@ -0,0 +1,26 @@
+; RUN: opt < %s -O3 -S | FileCheck %s
+ at gv = external global i32
+
+define i32 @main() nounwind {
+; CHECK-NOT: call i32 @foo
+  %1 = load i32* @gv, align 4
+  %2 = tail call i32 @foo(i32 %1)
+  unreachable
+}
+
+define internal i32 @foo(i32) alwaysinline {
+  br label %2
+
+; <label>:2                                       ; preds = %8, %1
+  %3 = phi i32 [ %0, %1 ], [ %10, %8 ]
+  %4 = phi i8* [ blockaddress(@foo, %2), %1 ], [ %6, %8 ]
+  %5 = icmp eq i32 %3, 1
+  %6 = select i1 %5, i8* blockaddress(@foo, %8), i8* %4
+  %7 = add nsw i32 %3, -1
+  br label %8
+
+; <label>:8                                       ; preds = %8, %2
+  %9 = phi i32 [ %7, %2 ], [ %10, %8 ]
+  %10 = add nsw i32 %9, -1
+  indirectbr i8* %6, [label %2, label %8]
+}
Index: test/Transforms/Inline/always-inline.ll
===================================================================
--- test/Transforms/Inline/always-inline.ll     (revision 206203)
+++ test/Transforms/Inline/always-inline.ll     (working copy)
@@ -78,7 +78,7 @@
   ret i32 %add
 }
 
-define i32 @inner5(i8* %addr) alwaysinline {
+define i32 @inner5(i8* %addr) {
 entry:
   indirectbr i8* %addr, [ label %one, label %two ]

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