[llvm-commits] [llvm] r62958 - /llvm/trunk/lib/Analysis/ScalarEvolution.cpp

[Nick Lewycky]

Author: nicholas
Date: Sun Jan 25 02:16:27 2009
New Revision: 62958

URL: http://llvm.org/viewvc/llvm-project?rev=62958&view=rev
Log:
Start generating arbitrary precision integer SCEVs. This removes the temporary
code that rounded up and capped the size.

Modified:
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=62958&r1=62957&r2=62958&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Sun Jan 25 02:16:27 2009
@@ -585,17 +585,7 @@
   }
 
   // We need at least W + T bits for the multiplication step
-  // FIXME: A temporary hack; we round up the bitwidths
-  // to the nearest power of 2 to be nice to the code generator.
-  unsigned CalculationBits = 1U << Log2_32_Ceil(W + T);
-  // FIXME: Temporary hack to avoid generating integers that are too wide.
-  // Although, it's not completely clear how to determine how much
-  // widening is safe; for example, on X86, we can't really widen
-  // beyond 64 because we need to be able to do multiplication
-  // that's CalculationBits wide, but on X86-64, we can safely widen up to
-  // 128 bits.
-  if (CalculationBits > 64)
-    return new SCEVCouldNotCompute();
+  unsigned CalculationBits = W + T;
 
   // Calcuate 2^T, at width T+W.
   APInt DivFactor = APInt(CalculationBits, 1).shl(T);