[llvm-commits] [llvm] r153966 - /llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp

[Chad Rosier]

Author: mcrosier
Date: Tue Apr  3 15:11:24 2012
New Revision: 153966

URL: http://llvm.org/viewvc/llvm-project?rev=153966&view=rev
Log:
Fix an issue in SimplifySetCC() specific to vector comparisons.

When folding X == X we need to check getBooleanContents() to determine if the
result is a vector of ones or a vector of negative ones. 

I tried creating a test case, but the problem seems to only be exposed on a
much older version of clang (around r144500).
rdar://10923049

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp?rev=153966&r1=153965&r2=153966&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp Tue Apr  3 15:11:24 2012
@@ -2432,8 +2432,16 @@
 
   if (N0 == N1) {
     // We can always fold X == X for integer setcc's.
-    if (N0.getValueType().isInteger())
-      return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
+    if (N0.getValueType().isInteger()) {
+      switch (getBooleanContents(N0.getValueType().isVector())) {
+      default: llvm_unreachable ("Unknown boolean content.");
+      case UndefinedBooleanContent: 
+      case ZeroOrOneBooleanContent: 
+        return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
+      case ZeroOrNegativeOneBooleanContent:
+        return DAG.getConstant(ISD::isTrueWhenEqual(Cond) ? -1 : 0, VT);
+      }
+    }
     unsigned UOF = ISD::getUnorderedFlavor(Cond);
     if (UOF == 2)   // FP operators that are undefined on NaNs.
       return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);