[llvm-commits] [llvm] r62985 - in /llvm/trunk: lib/Transforms/Scalar/CondPropagate.cpp test/Transforms/CondProp/2009-01-25-SingleEntryPHI.ll

[Chris Lattner]

Author: lattner
Date: Sun Jan 25 20:18:20 2009
New Revision: 62985

URL: http://llvm.org/viewvc/llvm-project?rev=62985&view=rev
Log:
Handle single-entry phi nodes gracefully in condprop.

Added:
    llvm/trunk/test/Transforms/CondProp/2009-01-25-SingleEntryPHI.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/CondPropagate.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/CondPropagate.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CondPropagate.cpp?rev=62985&r1=62984&r2=62985&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CondPropagate.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/CondPropagate.cpp Sun Jan 25 20:18:20 2009
@@ -126,6 +126,14 @@
   // one use (the branch), and is the only instruction besides the branch in the
   // block.
   PHINode *PN = cast<PHINode>(BI->getCondition());
+
+  if (PN->getNumIncomingValues() == 1) {
+    // Eliminate single-entry PHI nodes.
+    FoldSingleEntryPHINodes(PN->getParent());
+    return;
+  }
+  
+  
   if (!PN->hasOneUse()) return;
 
   BasicBlock *BB = BI->getParent();

Added: llvm/trunk/test/Transforms/CondProp/2009-01-25-SingleEntryPHI.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/CondProp/2009-01-25-SingleEntryPHI.ll?rev=62985&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/CondProp/2009-01-25-SingleEntryPHI.ll (added)
+++ llvm/trunk/test/Transforms/CondProp/2009-01-25-SingleEntryPHI.ll Sun Jan 25 20:18:20 2009
@@ -0,0 +1,37 @@
+; RUN: llvm-as < %s | opt -condprop | llvm-dis
+; PR3405
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @main(i32 %argc, i8** %argv) nounwind {
+entry:
+	br label %bb2
+
+bb2:		; preds = %bb.bb2_crit_edge, %entry
+	br i1 false, label %bb5.thread2, label %bb
+
+bb:		; preds = %bb2
+	br i1 false, label %bb3, label %bb.bb2_crit_edge
+
+bb.bb2_crit_edge:		; preds = %bb
+	br label %bb2
+
+bb3:		; preds = %bb
+	%.lcssa4 = phi i1 [ false, %bb ]		; <i1> [#uses=1]
+	br i1 %.lcssa4, label %bb5.thread, label %bb6
+
+bb5.thread:		; preds = %bb3
+	br label %bb7
+
+bb7:		; preds = %bb5.thread2, %bb5.thread
+	br label %UnifiedReturnBlock
+
+bb6:		; preds = %bb3
+	br label %UnifiedReturnBlock
+
+bb5.thread2:		; preds = %bb2
+	br label %bb7
+
+UnifiedReturnBlock:		; preds = %bb6, %bb7
+	ret i32 0
+}