[llvm-commits] [llvm] r73423 - in /llvm/trunk: lib/CodeGen/IfConversion.cpp test/CodeGen/ARM/ifcvt9.ll

[Evan Cheng]

Author: evancheng
Date: Mon Jun 15 16:24:34 2009
New Revision: 73423

URL: http://llvm.org/viewvc/llvm-project?rev=73423&view=rev
Log:
ifcvt should ignore cfg where true and false successors are the same.

Added:
    llvm/trunk/test/CodeGen/ARM/ifcvt9.ll
Modified:
    llvm/trunk/lib/CodeGen/IfConversion.cpp

Modified: llvm/trunk/lib/CodeGen/IfConversion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/IfConversion.cpp?rev=73423&r1=73422&r2=73423&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/IfConversion.cpp (original)
+++ llvm/trunk/lib/CodeGen/IfConversion.cpp Mon Jun 15 16:24:34 2009
@@ -547,7 +547,11 @@
     // fallthrough.
     if (!BBI.FalseBB)
       BBI.FalseBB = findFalseBlock(BBI.BB, BBI.TrueBB);  
-    assert(BBI.FalseBB && "Expected to find the fallthrough block!");
+    if (!BBI.FalseBB) {
+      // Malformed bcc? True and false blocks are the same?
+      BBI.IsUnpredicable = true;
+      return;
+    }
   }
 
   // Then scan all the instructions.
@@ -663,6 +667,13 @@
     return BBI;
   }
 
+  // Do not ifcvt if true and false fallthrough blocks are the same.
+  if (!BBI.FalseBB) {
+    BBI.IsBeingAnalyzed = false;
+    BBI.IsAnalyzed = true;
+    return BBI;
+  }
+
   BBInfo &TrueBBI  = AnalyzeBlock(BBI.TrueBB, Tokens);
   BBInfo &FalseBBI = AnalyzeBlock(BBI.FalseBB, Tokens);
 

Added: llvm/trunk/test/CodeGen/ARM/ifcvt9.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/ifcvt9.ll?rev=73423&view=auto

==============================================================================
--- llvm/trunk/test/CodeGen/ARM/ifcvt9.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/ifcvt9.ll Mon Jun 15 16:24:34 2009
@@ -0,0 +1,12 @@
+; RUN: llvm-as < %s | llc -march=arm
+
+define fastcc void @t() nounwind {
+entry:
+	br i1 undef, label %bb.i.i3, label %growMapping.exit
+
+bb.i.i3:		; preds = %entry
+	unreachable
+
+growMapping.exit:		; preds = %entry
+	unreachable
+}