[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

llvm-svn: 227089
diff --git a/llvm/test/CodeGen/Mips/llvm-ir/add.ll b/llvm/test/CodeGen/Mips/llvm-ir/add.ll
index 8890992..83774ed 100644
--- a/llvm/test/CodeGen/Mips/llvm-ir/add.ll
+++ b/llvm/test/CodeGen/Mips/llvm-ir/add.ll
@@ -83,3 +83,33 @@
   %r = add i64 %a, %b
   ret i64 %r
 }
+
+define signext i128 @add_i128(i128 signext %a, i128 signext %b) {
+entry:
+; ALL-LABEL: add_i128:
+
+  ; GP32:       lw        $[[T0:[0-9]+]], 28($sp)
+  ; GP32:       addu      $[[T1:[0-9]+]], $7, $[[T0]]
+  ; GP32:       sltu      $[[T2:[0-9]+]], $[[T1]], $[[T0]]
+  ; GP32:       lw        $[[T3:[0-9]+]], 24($sp)
+  ; GP32:       addu      $[[T4:[0-9]+]], $[[T2]], $[[T3]]
+  ; GP32:       addu      $[[T5:[0-9]+]], $6, $[[T4]]
+  ; GP32:       sltu      $[[T6:[0-9]+]], $[[T5]], $[[T3]]
+  ; GP32:       lw        $[[T7:[0-9]+]], 20($sp)
+  ; GP32:       addu      $[[T8:[0-9]+]], $[[T6]], $[[T7]]
+  ; GP32:       lw        $[[T9:[0-9]+]], 16($sp)
+  ; GP32:       addu      $3, $5, $[[T8]]
+  ; GP32:       sltu      $[[T10:[0-9]+]], $3, $[[T7]]
+  ; GP32:       addu      $[[T11:[0-9]+]], $[[T10]], $[[T9]]
+  ; GP32:       addu      $2, $4, $[[T11]]
+  ; GP32:       move      $4, $[[T5]]
+  ; GP32:       move      $5, $[[T1]]
+
+  ; GP64:       daddu     $3, $5, $7
+  ; GP64:       sltu      $[[T0:[0-9]+]], $3, $7
+  ; GP64:       daddu     $[[T1:[0-9]+]], $[[T0]], $6
+  ; GP64:       daddu     $2, $4, $[[T1]]
+
+  %r = add i128 %a, %b
+  ret i128 %r
+}