[llvm] r174156 - Revert r174152. The shift amount may overflow and in that case this transformation is illegal.

[Nadav Rotem]

Author: nadav
Date: Fri Feb  1 01:59:33 2013
New Revision: 174156

URL: http://llvm.org/viewvc/llvm-project?rev=174156&view=rev
Log:
Revert r174152. The shift amount may overflow and in that case this transformation is illegal. 

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

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp?rev=174156&r1=174155&r2=174156&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineShifts.cpp Fri Feb  1 01:59:33 2013
@@ -709,12 +709,6 @@ Instruction *InstCombiner::visitShl(Bina
       match(I.getOperand(1), m_Constant(C2)))
     return BinaryOperator::CreateShl(ConstantExpr::getShl(C1, C2), A);
 
-  // shl (c1 , add(y , c2)) -> (shl (shl(c1, c2)), y)
-  if (match(I.getOperand(0), m_Constant(C1)) &&
-      match(I.getOperand(1), m_Add(m_Value(A), m_Constant(C2)))) {
-    return BinaryOperator::CreateShl(ConstantExpr::getShl(C1, C2), A);
-  }
-
   return 0;
 }
 

Modified: llvm/trunk/test/Transforms/InstCombine/shift.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/shift.ll?rev=174156&r1=174155&r2=174156&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/shift.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/shift.ll Fri Feb  1 01:59:33 2013
@@ -745,23 +745,3 @@ define i32 @test62(i32 %x) {
 ; CHECK: @test62
 ; CHECK: ashr exact i32 %x, 3
 }
-
-; CHECK: @test63
-; CHECK: shl <4 x i32> <i32 1, i32 2, i32 4, i32 8>, %B
-define <4 x i32> @test63(i32 %n) {
-entry:
-  %K = insertelement <4 x i32> undef, i32 %n, i32 0
-  %B = shufflevector <4 x i32> %K, <4 x i32> undef, <4 x i32> zeroinitializer
-  %A = add <4 x i32> %B, <i32 0, i32 1, i32 2, i32 3>
-  %T = shl <4 x i32> <i32 1, i32 1, i32 1, i32 1>, %A
-  ret <4 x i32> %T
-}
-
-; CHECK: @test64
-; CHECK: shl i32 524288, %n
-define i32 @test64(i32 %n) {
-entry:
-  %A = add i32 %n, 19
-  %T = shl i32 1 , %A
-  ret i32 %T
-}