[llvm-commits] [llvm] r133659 - in /llvm/trunk: lib/CodeGen/TailDuplication.cpp test/CodeGen/X86/tail-dup-addr.ll

[Rafael Espindola]

Author: rafael
Date: Wed Jun 22 17:31:57 2011
New Revision: 133659

URL: http://llvm.org/viewvc/llvm-project?rev=133659&view=rev
Log:
Reenable tail duplication of bb with just an unconditional jump, but
don't remove blocks that have their address taken.

Added:
    llvm/trunk/test/CodeGen/X86/tail-dup-addr.ll
Modified:
    llvm/trunk/lib/CodeGen/TailDuplication.cpp

Modified: llvm/trunk/lib/CodeGen/TailDuplication.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TailDuplication.cpp?rev=133659&r1=133658&r2=133659&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TailDuplication.cpp (original)
+++ llvm/trunk/lib/CodeGen/TailDuplication.cpp Wed Jun 22 17:31:57 2011
@@ -207,7 +207,7 @@
       // TailBB's immediate successors are now successors of those predecessors
       // which duplicated TailBB. Add the predecessors as sources to the PHI
       // instructions.
-      bool isDead = MBB->pred_empty();
+      bool isDead = MBB->pred_empty() && !MBB->hasAddressTaken();
       if (PreRegAlloc)
         UpdateSuccessorsPHIs(MBB, isDead, TDBBs, Succs);
 
@@ -568,9 +568,9 @@
 TailDuplicatePass::isSimpleBB(MachineBasicBlock *TailBB) {
   if (TailBB->succ_size() != 1)
     return false;
-  MachineBasicBlock::iterator I = TailBB->getFirstNonPHI();
+  MachineBasicBlock::iterator I = TailBB->begin();
   MachineBasicBlock::iterator E = TailBB->end();
-  while (I->isDebugValue() && I != E)
+  while (I != E && I->isDebugValue())
     ++I;
   if (I == E)
     return true;
@@ -712,7 +712,7 @@
   DenseSet<unsigned> UsedByPhi;
   getRegsUsedByPHIs(*TailBB, &UsedByPhi);
 
-  if (0 && isSimpleBB(TailBB))
+  if (isSimpleBB(TailBB))
     return duplicateSimpleBB(TailBB, TDBBs, UsedByPhi, Copies);
 
   // Iterate through all the unique predecessors and tail-duplicate this

Added: llvm/trunk/test/CodeGen/X86/tail-dup-addr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/tail-dup-addr.ll?rev=133659&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/tail-dup-addr.ll (added)
+++ llvm/trunk/test/CodeGen/X86/tail-dup-addr.ll Wed Jun 22 17:31:57 2011
@@ -0,0 +1,28 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
+
+; Test that we don't drop a block that has its address taken.
+
+; CHECK: Ltmp1:                                  ## Block address taken
+; CHECK: Ltmp2:                                  ## Block address taken
+
+ at a = common global i32 0, align 4
+ at p = common global i8* null, align 8
+
+define void @foo() noreturn nounwind uwtable ssp {
+entry:
+  %tmp = load i32* @a, align 4
+  %foo = icmp eq i32 0, %tmp
+  br i1 %foo, label %sw.bb, label %sw.default
+
+sw.bb:                                            ; preds = %entry
+  store i8* blockaddress(@foo, %sw.bb1), i8** @p, align 8
+  br label %sw.bb1
+
+sw.bb1:                                           ; preds = %sw.default, %sw.bb, %entry
+  store i8* blockaddress(@foo, %sw.default), i8** @p, align 8
+  br label %sw.default
+
+sw.default:                                       ; preds = %sw.bb1, %entry
+  store i8* blockaddress(@foo, %sw.bb1), i8** @p, align 8
+  br label %sw.bb1
+}