[mips] Enable arithmetic and binary operations for the i128 data type.

Summary:
This patch adds support for some operations that were missing from
128-bit integer types (add/sub/mul/sdiv/udiv... etc.). With these
changes we can support the __int128_t and __uint128_t data types
from C/C++.

Depends on D7125

Reviewers: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7143

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227089 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/Mips/llvm-ir/srem.ll

@@ -114,3 +114,16 @@ entry:
   %r = srem i64 %a, %b
   ret i64 %r
 }
+
+define signext i128 @srem_i128(i128 signext %a, i128 signext %b) {
+entry:
+; ALL-LABEL: srem_i128:
+
+  ; GP32:         lw      $25, %call16(__modti3)($gp)
+
+  ; GP64-NOT-R6:  ld      $25, %call16(__modti3)($gp)
+  ; 64-R6:        ld      $25, %call16(__modti3)($gp)
+
+  %r = srem i128 %a, %b
+  ret i128 %r
+}