[llvm-commits] CVS: llvm/lib/Transforms/Utils/CloneFunction.cpp

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Utils:

CloneFunction.cpp updated: 1.30 -> 1.31
---
Log message:

Second half of the fix for Transforms/Inline/inline_cleanup.ll

This folds unconditional branches that are often produced by code 
specialization.


---
Diffs of the changes:  (+28 -2)

 CloneFunction.cpp |   30 ++++++++++++++++++++++++++++--
 1 files changed, 28 insertions(+), 2 deletions(-)


Index: llvm/lib/Transforms/Utils/CloneFunction.cpp
diff -u llvm/lib/Transforms/Utils/CloneFunction.cpp:1.30 llvm/lib/Transforms/Utils/CloneFunction.cpp:1.31
--- llvm/lib/Transforms/Utils/CloneFunction.cpp:1.30	Thu Jun  1 15:02:28 2006
+++ llvm/lib/Transforms/Utils/CloneFunction.cpp	Wed Sep 13 16:27:00 2006
@@ -449,6 +449,32 @@
       }
     }
   }
-}
-
+  
+  // Now that the inlined function body has been fully constructed, go through
+  // and zap unconditional fall-through branches.  This happen all the time when
+  // specializing code: code specialization turns conditional branches into
+  // uncond branches, and this code folds them.
+  Function::iterator I = cast<BasicBlock>(ValueMap[&OldFunc->getEntryBlock()]);
+  while (I != NewFunc->end()) {
+    BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
+    if (!BI || BI->isConditional()) { ++I; continue; }
+    
+    BasicBlock *Dest = BI->getSuccessor(0);
+    if (!Dest->getSinglePredecessor()) { ++I; continue; }
+    
+    // We know all single-entry PHI nodes in the inlined function have been
+    // removed, so we just need to splice the blocks.
+    BI->eraseFromParent();
+    
+    // Move all the instructions in the succ to the pred.
+    I->getInstList().splice(I->end(), Dest->getInstList());
+    
+    // Make all PHI nodes that referred to Dest now refer to I as their source.
+    Dest->replaceAllUsesWith(I);
 
+    // Remove the dest block.
+    Dest->eraseFromParent();
+    
+    // Do not increment I, iteratively merge all things this block branches to.
+  }
+}