[llvm-commits] [llvm] r131885 - /llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

[Chris Lattner]

Author: lattner
Date: Sun May 22 19:09:55 2011
New Revision: 131885

URL: http://llvm.org/viewvc/llvm-project?rev=131885&view=rev
Log:
use the valuetracking isPowerOfTwo function, which is more powerful than checking
for a constant directly.  Thanks to Duncan for pointing this out.

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp?rev=131885&r1=131884&r2=131885&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp Sun May 22 19:09:55 2011
@@ -31,13 +31,13 @@
   
   // ((1 << A) >>u B) --> (1 << (A-B))
   // Because V cannot be zero, we know that B is less than A.
-  Value *A = 0, *B = 0; ConstantInt *One = 0;
-  if (match(V, m_LShr(m_OneUse(m_Shl(m_ConstantInt(One), m_Value(A))),
+  Value *A = 0, *B = 0, *PowerOf2 = 0;
+  if (match(V, m_LShr(m_OneUse(m_Shl(m_Value(PowerOf2), m_Value(A))),
                       m_Value(B))) &&
       // The "1" can be any value known to be a power of 2.
-      One->getValue().isPowerOf2()) {
+      isPowerOfTwo(PowerOf2, IC.getTargetData())) {
     A = IC.Builder->CreateSub(A, B, "tmp");
-    return IC.Builder->CreateShl(One, A);
+    return IC.Builder->CreateShl(PowerOf2, A);
   }
   
   // TODO: Lots more we could do here: