commit 05b72c1fd868b0d3c9596680e63a9de59860f3d1
author Ahmed Bougacha <ahmed.bougacha@gmail.com> Sat Apr 18 23:06:04 2015 +0000
committer Ahmed Bougacha <ahmed.bougacha@gmail.com> Sat Apr 18 23:06:04 2015 +0000
tree 7248b76660b1985531ab012be3b887f8c0402097
parent 6292d50eda0f33e5477e3494c27d375151771183

[MemCpyOpt] Don't force i64 when promoting memset/memcpy sizes.

Harden r235258 to support any integer bitwidth.  The quick glance at
the reference made me think only i32 and i64 were valid types, but
they're not special, so any overload is legal.

Thanks to David Majnemer for noticing!

llvm-svn: 235261

llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp

diff --git a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index 550757a..563e49c 100644
--- a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -876,10 +876,13 @@
 
   IRBuilder<> Builder(MemCpy->getNextNode());
 
-  // If the sizes have different types (i32 vs i64), promote both to i64.
+  // If the sizes have different types, zext the smaller one.
   if (DestSize->getType() != SrcSize->getType()) {
-    DestSize = Builder.CreateZExt(DestSize, Builder.getInt64Ty());
-    SrcSize = Builder.CreateZExt(SrcSize, Builder.getInt64Ty());
+    if (DestSize->getType()->getIntegerBitWidth() >
+        SrcSize->getType()->getIntegerBitWidth())
+      SrcSize = Builder.CreateZExt(SrcSize, DestSize->getType());
+    else
+      DestSize = Builder.CreateZExt(DestSize, SrcSize->getType());
   }
 
   Value *MemsetLen =