[llvm-commits] [llvm] r82386 - in /llvm/trunk: lib/VMCore/ConstantFold.cpp test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll

[Nick Lewycky]

Author: nicholas
Date: Sun Sep 20 02:21:39 2009
New Revision: 82386

URL: http://llvm.org/viewvc/llvm-project?rev=82386&view=rev
Log:
Fold 'icmp eq (icmp), true' into an xor(icmp).

Modified:
    llvm/trunk/lib/VMCore/ConstantFold.cpp
    llvm/trunk/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll

Modified: llvm/trunk/lib/VMCore/ConstantFold.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/ConstantFold.cpp?rev=82386&r1=82385&r2=82386&view=diff

==============================================================================
--- llvm/trunk/lib/VMCore/ConstantFold.cpp (original)
+++ llvm/trunk/lib/VMCore/ConstantFold.cpp Sun Sep 20 02:21:39 2009
@@ -1428,6 +1428,20 @@
       }
   }
 
+  // If the comparison is a comparison between two i1's, simplify it.
+  if (C1->getType() == Type::getInt1Ty(Context)) {
+    switch(pred) {
+    case ICmpInst::ICMP_EQ:
+      if (isa<ConstantInt>(C2))
+        return ConstantExpr::getXor(C1, ConstantExpr::getNot(C2));
+      return ConstantExpr::getXor(ConstantExpr::getNot(C1), C2);
+    case ICmpInst::ICMP_NE:
+      return ConstantExpr::getXor(C1, C2);
+    default:
+      break;
+    }
+  }
+
   if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
     APInt V1 = cast<ConstantInt>(C1)->getValue();
     APInt V2 = cast<ConstantInt>(C2)->getValue();

Modified: llvm/trunk/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll?rev=82386&r1=82385&r2=82386&view=diff

==============================================================================
--- llvm/trunk/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll (original)
+++ llvm/trunk/test/Transforms/ConstProp/2009-09-19-ConstFold-i1-ConstExpr.ll Sun Sep 20 02:21:39 2009
@@ -27,3 +27,12 @@
 ; CHECK: @I = global i1 icmp ult (i8* @X, i8* @Y) ; <i1*> [#uses=0]
 @J = global i1 xor (i1 icmp ult (i8* @X, i8* @Y), i1 true)
 ; CHECK: @J = global i1 icmp uge (i8* @X, i8* @Y) ; <i1*> [#uses=0]
+
+ at K = global i1 icmp eq (i1 icmp ult (i8* @X, i8* @Y), i1 false)
+; CHECK: @K = global i1 icmp uge (i8* @X, i8* @Y) ; <i1*> [#uses=0]
+ at L = global i1 icmp eq (i1 icmp ult (i8* @X, i8* @Y), i1 true)
+; CHECK: @L = global i1 icmp ult (i8* @X, i8* @Y) ; <i1*> [#uses=0]
+ at M = global i1 icmp ne (i1 icmp ult (i8* @X, i8* @Y), i1 true)
+; CHECK: @M = global i1 icmp uge (i8* @X, i8* @Y) ; <i1*> [#uses=0]
+ at N = global i1 icmp ne (i1 icmp ult (i8* @X, i8* @Y), i1 false)
+; CHECK: @N = global i1 icmp ult (i8* @X, i8* @Y) ; <i1*> [#uses=0]