commit 9a2cfffdb6340c54ff553c1b81364d0f17fa8f45
author Preston Gurd <preston.gurd@intel.com> Mon Mar 04 18:13:57 2013 +0000
committer Preston Gurd <preston.gurd@intel.com> Mon Mar 04 18:13:57 2013 +0000
tree 999ad911d34f3f83d1140500e731228c5f07df84
parent ff4faabd2d98776372f45f7592482c9239cc40f2

Bypass Slow Divides

* Only apply divide bypass optimization when not optimizing for size. 
* Fixed bug caused by constant for 0 value of type Int32,
  used dividend type to generate the constant instead.
* For atom x86-64 apply the divide bypass to use 16-bit divides instead of
  64-bit divides when operand values are small enough.
* Added lit tests for 64-bit divide bypass.

Patch by Tyler Nowicki!




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176442 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/BypassSlowDivision.cpp

diff --git a/lib/Transforms/Utils/BypassSlowDivision.cpp b/lib/Transforms/Utils/BypassSlowDivision.cpp
index 00cda8e..1f517d0 100644
--- a/lib/Transforms/Utils/BypassSlowDivision.cpp
+++ b/lib/Transforms/Utils/BypassSlowDivision.cpp
@@ -163,7 +163,7 @@
   Value *AndV = MainBuilder.CreateAnd(OrV, BitMask);
 
   // Compare operand values and branch
-  Value *ZeroV = MainBuilder.getInt32(0);
+  Value *ZeroV = ConstantInt::getSigned(Dividend->getType(), 0);
   Value *CmpV = MainBuilder.CreateICmpEQ(AndV, ZeroV);
   MainBuilder.CreateCondBr(CmpV, FastBB, SlowBB);
 
@@ -244,7 +244,7 @@
 
     // Get bitwidth of div/rem instruction
     IntegerType *T = cast<IntegerType>(J->getType());
-    int bitwidth = T->getBitWidth();
+    unsigned int bitwidth = T->getBitWidth();
 
     // Continue if bitwidth is not bypassed
     DenseMap<unsigned int, unsigned int>::const_iterator BI = BypassWidths.find(bitwidth);