[llvm-commits] [llvm] r125711 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineAddSub.cpp test/Transforms/InstCombine/add2.ll

[Chris Lattner]

Author: lattner
Date: Wed Feb 16 20:23:02 2011
New Revision: 125711

URL: http://llvm.org/viewvc/llvm-project?rev=125711&view=rev
Log:
preserve NUW/NSW when transforming add x,x

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
    llvm/trunk/test/Transforms/InstCombine/add2.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp?rev=125711&r1=125710&r2=125711&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp Wed Feb 16 20:23:02 2011
@@ -147,8 +147,13 @@
     return BinaryOperator::CreateXor(LHS, RHS);
 
   // X + X --> X << 1
-  if (LHS == RHS && I.getType()->isIntegerTy())
-    return BinaryOperator::CreateShl(LHS, ConstantInt::get(I.getType(), 1));
+  if (LHS == RHS && I.getType()->isIntegerTy()) {
+    BinaryOperator *New =
+      BinaryOperator::CreateShl(LHS, ConstantInt::get(I.getType(), 1));
+    New->setHasNoSignedWrap(I.hasNoSignedWrap());
+    New->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
+    return New;
+  }
 
   // -A + B  -->  B - A
   // -A + -B  -->  -(A + B)

Modified: llvm/trunk/test/Transforms/InstCombine/add2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/add2.ll?rev=125711&r1=125710&r2=125711&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/add2.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/add2.ll Wed Feb 16 20:23:02 2011
@@ -33,3 +33,11 @@
 ; CHECK-NEXT: ret i32
 }
 
+define i32 @test4(i32 %A) {
+  %B = add nuw i32 %A, %A
+  ret i32 %B
+; CHECK: @test4
+; CHECK-NEXT: %B = shl nuw i32 %A, 1
+; CHECK-NEXT: ret i32 %B
+}
+