[llvm-commits] [llvm] r85893 - /llvm/trunk/include/llvm/Support/StandardPasses.h

[Duncan Sands]

Author: baldrick
Date: Tue Nov  3 03:40:08 2009
New Revision: 85893

URL: http://llvm.org/viewvc/llvm-project?rev=85893&view=rev
Log:
Run the functionattrs pass after the inliner, and not before.
This makes both logical sense (see below) and increases the
number of functions marked readnone/readonly by about 1-2%
in practice.  The number of functions marked nocapture goes
up by about 5-10%.  The reason it makes sense is shown by
the following example: if you run -functionattrs -inline on
it, then no attributes are assigned.  But if you instead run
-inline -functionattrs then @f is marked readnone because the
simplifications produced by the inliner eliminate the store.

@x = external global i32

define void @w(i1 %b) {
        br i1 %b, label %write, label %return
write:
        store i32 1, i32 *@x
        br label %return
return:
        ret void
}

define void @f() {
        call void @w(i1 0)
        ret void
}


Modified:
    llvm/trunk/include/llvm/Support/StandardPasses.h

Modified: llvm/trunk/include/llvm/Support/StandardPasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/StandardPasses.h?rev=85893&r1=85892&r2=85893&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Support/StandardPasses.h (original)
+++ llvm/trunk/include/llvm/Support/StandardPasses.h Tue Nov  3 03:40:08 2009
@@ -107,13 +107,12 @@
     PM->add(createCFGSimplificationPass());     // Clean up after IPCP & DAE
     
     // Start of CallGraph SCC passes.
-    if (UnitAtATime) {
-      if (HaveExceptions)
-        PM->add(createPruneEHPass());           // Remove dead EH info
-      PM->add(createFunctionAttrsPass());       // Set readonly/readnone attrs
-    }
+    if (UnitAtATime && HaveExceptions)
+      PM->add(createPruneEHPass());           // Remove dead EH info
     if (InliningPass)
       PM->add(InliningPass);
+    if (UnitAtATime)
+      PM->add(createFunctionAttrsPass());       // Set readonly/readnone attrs
     if (OptimizationLevel > 2)
       PM->add(createArgumentPromotionPass());   // Scalarize uninlined fn args