[PATCH] [PATCH] Teach the Inliner about attribute optnone

[Andrea Di Biagio]

  I uploaded new version of the patch.

  As suggested by Eric, I changed the description of attribute optnone in docs/LangRef.rst explaining why `optnone' functions are not inlined.

  Please let me know what do you think.

  Thanks
  Andrea

http://llvm-reviews.chandlerc.com/D1642

CHANGE SINCE LAST DIFF
  http://llvm-reviews.chandlerc.com/D1642?vs=4172&id=4175#toc

Files:
  docs/LangRef.rst
  lib/Analysis/IPA/InlineCost.cpp
  test/Transforms/Inline/inline-optnone.ll

Index: docs/LangRef.rst
===================================================================
--- docs/LangRef.rst
+++ docs/LangRef.rst
@@ -887,7 +887,9 @@
     attribute; this attribute is also incompatible
     with the ``minsize`` attribute and the ``optsize`` attribute.
     
-    The inliner should never inline this function in any situation.
+    The inliner should never inline this function in any situation; this
+    is to guarantee that the code coming from an optnone function is
+    never optimized.
     Only functions with the ``alwaysinline`` attribute are valid
     candidates for inlining inside the body of this function.
 ``optsize``
Index: lib/Analysis/IPA/InlineCost.cpp
===================================================================
--- lib/Analysis/IPA/InlineCost.cpp
+++ lib/Analysis/IPA/InlineCost.cpp
@@ -1201,6 +1201,16 @@
     return llvm::InlineCost::getNever();
   }
 
+  // Never inline functions without always-inline attributes if the
+  // caller has optnone attribute.
+  if (CS.getCaller()->hasFnAttribute(Attribute::OptimizeNone))
+    return llvm::InlineCost::getNever();
+
+  // Don't inline this call if the caller has the optnone attribute
+  // (and the callee doesn't have always_inline, checked previously).
+  if (Callee->hasFnAttribute(Attribute::OptimizeNone))
+    return llvm::InlineCost::getNever();
+
   // Never inline functions with conflicting attributes (unless callee has
   // always-inline attribute).
   if (!functionsHaveCompatibleAttributes(CS.getCaller(), Callee))
Index: test/Transforms/Inline/inline-optnone.ll
===================================================================
--- test/Transforms/Inline/inline-optnone.ll
+++ test/Transforms/Inline/inline-optnone.ll
@@ -0,0 +1,52 @@
+; RUN: opt < %s -inline -S | FileCheck %s
+
+; Test that functions with attribute optnone are not inlined.
+; Also test that only functions with attribute alwaysinline
+; are valid candidate for inlining if the caller has optnone attribute.
+
+; Function Attrs: alwaysinline nounwind readnone uwtable
+define i32 @alwaysInlineFunction(i32 %a) #0 {
+entry:
+  %mul = mul i32 %a, %a
+  ret i32 %mul
+}
+
+; Function Attrs: nounwind readnone uwtable
+define i32 @simpleFunction(i32 %a) #1 {
+entry:
+  %add = add i32 %a, %a
+  ret i32 %add
+}
+
+; Function Attrs: nounwind optnone readnone uwtable
+define i32 @OptnoneFunction(i32 %a) #2 {
+entry:
+  %0 = tail call i32 @alwaysInlineFunction(i32 %a)
+  %1 = tail call i32 @simpleFunction(i32 %a)
+  %add = add i32 %0, %1
+  ret i32 %add
+}
+
+; CHECK-LABEL: @OptnoneFunction
+; CHECK-NOT: call i32 @alwaysInlineFunction(i32 %a)
+; CHECK: call i32 @simpleFunction(i32 %a)
+; CHECK: ret
+
+; Function Attrs: nounwind readnone uwtable
+define i32 @bar(i32 %a) #1 {
+entry:
+  %0 = tail call i32 @OptnoneFunction(i32 5)
+  %1 = tail call i32 @simpleFunction(i32 6)
+  %add = add i32 %0, %1
+  ret i32 %add
+}
+
+; CHECK-LABEL: @bar
+; CHECK: call i32 @OptnoneFunction(i32 5)
+; CHECK-NOT: call i32 @simpleFunction(i32 6)
+; CHECK: ret
+
+
+attributes #0 = { alwaysinline nounwind readnone uwtable }
+attributes #1 = { nounwind readnone uwtable }
+attributes #2 = { nounwind optnone readnone uwtable }
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D1642.2.patch
Type: text/x-patch
Size: 3203 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20130910/490f1408/attachment.bin>