[llvm-commits] [llvm] r169209 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp test/Transforms/InstCombine/shift.ll

[Shuxin Yang]

Author: shuxin_yang
Date: Mon Dec  3 21:28:32 2012
New Revision: 169209

URL: http://llvm.org/viewvc/llvm-project?rev=169209&view=rev
Log:
rdar://12329730 (2nd part, revised)

The type of shirt-right (logical or arithemetic) should remain unchanged 
when transforming  "X << C1 >> C2" into "X << (C1-C2)"

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
    llvm/trunk/test/Transforms/InstCombine/shift.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp?rev=169209&r1=169208&r2=169209&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp Mon Dec  3 21:28:32 2012
@@ -876,7 +876,8 @@
       New->setHasNoUnsignedWrap(Orig->hasNoUnsignedWrap());
     } else {
       Constant *Amt = ConstantInt::get(VarX->getType(), ShrAmt - ShlAmt);
-      New = BinaryOperator::CreateLShr(VarX, Amt);
+      New = isLshr ? BinaryOperator::CreateLShr(VarX, Amt) :
+                     BinaryOperator::CreateAShr(VarX, Amt);
     }
 
     return InsertNewInstWith(New, *Shl);

Modified: llvm/trunk/test/Transforms/InstCombine/shift.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/shift.ll?rev=169209&r1=169208&r2=169209&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/shift.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/shift.ll Mon Dec  3 21:28:32 2012
@@ -723,7 +723,7 @@
   %or = or i32 %shl, 1
   ret i32 %or
 ; CHECK: @test60
-; CHECK: lshr i32 %x, 3
+; CHECK: ashr i32 %x, 3
 }