[llvm-commits] CVS: llvm/lib/CodeGen/BranchFolding.cpp

[Dale Johannesen]

Changes in directory llvm/lib/CodeGen:

BranchFolding.cpp updated: 1.60 -> 1.61
---
Log message:

Arrange for only 1 of multiple branches to landing pad to be kept.
Do not remove empty landing pads (EH table needs to be updated)


---
Diffs of the changes:  (+13 -4)

 BranchFolding.cpp |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)


Index: llvm/lib/CodeGen/BranchFolding.cpp
diff -u llvm/lib/CodeGen/BranchFolding.cpp:1.60 llvm/lib/CodeGen/BranchFolding.cpp:1.61
--- llvm/lib/CodeGen/BranchFolding.cpp:1.60	Tue May 29 19:32:01 2007
+++ llvm/lib/CodeGen/BranchFolding.cpp	Thu May 31 16:54:00 2007
@@ -684,18 +684,26 @@
     }
   }
   
-  MachineBasicBlock::pred_iterator SI = MBB.succ_begin();
+  MachineBasicBlock::succ_iterator SI = MBB.succ_begin();
+  bool foundPad = false;
   while (SI != MBB.succ_end()) {
     if (*SI == DestA && DestA == DestB) {
       DestA = DestB = 0;
+      if ((*SI)->isLandingPad())
+        foundPad = true;
       ++SI;
     } else if (*SI == DestA) {
       DestA = 0;
+      if ((*SI)->isLandingPad())
+        foundPad = true;
       ++SI;
     } else if (*SI == DestB) {
       DestB = 0;
+      if ((*SI)->isLandingPad())
+        foundPad = true;
       ++SI;
-    } else if ((*SI)->isLandingPad()) {
+    } else if ((*SI)->isLandingPad() && !foundPad) {
+      foundPad = true;
       ++SI;
     } else {
       // Otherwise, this is a superfluous edge, remove it.
@@ -832,8 +840,9 @@
   ++FallThrough;
   
   // If this block is empty, make everyone use its fall-through, not the block
-  // explicitly.
-  if (MBB->empty()) {
+  // explicitly.  Landing pads should not do this since the landing-pad table
+  // points to this block.
+  if (MBB->empty() && !MBB->isLandingPad()) {
     // Dead block?  Leave for cleanup later.
     if (MBB->pred_empty()) return;