[opaque pointer types] Pass value type to GetElementPtr creation.

This cleans up all GetElementPtr creation in LLVM to explicitly pass a
value type rather than deriving it from the pointer's element-type.

Differential Revision: https://reviews.llvm.org/D57173

llvm-svn: 352913
diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 5181f49..da368b2 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -737,7 +737,8 @@
 
     // strstr("abcd", "bc") -> gep((char*)"abcd", 1)
     Value *Result = castToCStr(CI->getArgOperand(0), B);
-    Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr");
+    Result =
+        B.CreateConstInBoundsGEP1_64(B.getInt8Ty(), Result, Offset, "strstr");
     return B.CreateBitCast(Result, CI->getType());
   }