[llvm-commits] [llvm] r124527 - in /llvm/trunk: lib/Transforms/Scalar/TailRecursionElimination.cpp test/Transforms/TailCallElim/dup_tail.ll

[Evan Cheng]

Author: evancheng
Date: Fri Jan 28 22:53:35 2011
New Revision: 124527

URL: http://llvm.org/viewvc/llvm-project?rev=124527&view=rev
Log:
Add a test for TCE return duplication.

Added:
    llvm/trunk/test/Transforms/TailCallElim/dup_tail.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp?rev=124527&r1=124526&r2=124527&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp Fri Jan 28 22:53:35 2011
@@ -72,6 +72,7 @@
 using namespace llvm;
 
 STATISTIC(NumEliminated, "Number of tail calls removed");
+STATISTIC(NumRetDuped,   "Number of return duplicated");
 STATISTIC(NumAccumAdded, "Number of accumulators introduced");
 
 namespace {
@@ -606,6 +607,7 @@
       EliminateRecursiveTailCall(CI, FoldReturnIntoUncondBranch(Ret, BB, Pred),
                                  OldEntry, TailCallsAreMarkedTail, ArgumentPHIs,
                                  CannotTailCallElimCallsMarkedTail);
+      ++NumRetDuped;
       Change = true;
     }
   }

Added: llvm/trunk/test/Transforms/TailCallElim/dup_tail.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/TailCallElim/dup_tail.ll?rev=124527&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/TailCallElim/dup_tail.ll (added)
+++ llvm/trunk/test/Transforms/TailCallElim/dup_tail.ll Fri Jan 28 22:53:35 2011
@@ -0,0 +1,23 @@
+; Duplicate the return into if.end to enable TCE.
+; RUN: opt %s -tailcallelim -stats -disable-output |& grep {Number of return duplicated}
+
+define i32 @fib(i32 %n) nounwind ssp {
+entry:
+  %cmp = icmp slt i32 %n, 2
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  br label %return
+
+if.end:                                           ; preds = %entry
+  %sub = add nsw i32 %n, -2
+  %call = call i32 @fib(i32 %sub)
+  %sub3 = add nsw i32 %n, -1
+  %call4 = call i32 @fib(i32 %sub3)
+  %add = add nsw i32 %call, %call4
+  br label %return
+
+return:                                           ; preds = %if.end, %if.then
+  %retval.0 = phi i32 [ 1, %if.then ], [ %add, %if.end ]
+  ret i32 %retval.0
+}