[mips] MIPS-IV is broadly the same as MIPS64 so duplicate all -mcpu=mips64 tests with -mcpu=mips4 as a starting point

Summary:
Two exceptions to this:
  test/CodeGen/Mips/octeon.ll
  test/CodeGen/Mips/octeon_popcnt.ll
these test extensions to MIPS64

One test is altered for MIPS-IV:
  test/CodeGen/Mips/mips64countleading.ll
    Tests dclo/dclz which were added in MIPS64. The MIPS-IV version tests
    that dclo/dclz are not emitted.

Four tests fail and are not in this patch:
  test/CodeGen/Mips/abicalls.ll
  test/CodeGen/Mips/fcopysign-f32-f64.ll
  test/CodeGen/Mips/fcopysign.ll
  test/CodeGen/Mips/stack-alignment.ll

Depends on D3343

Reviewers: matheusalmeida, vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D3344

llvm-svn: 206185
diff --git a/llvm/test/CodeGen/Mips/mips64ext.ll b/llvm/test/CodeGen/Mips/mips64ext.ll
index 02a35f8..22ea0eb 100644
--- a/llvm/test/CodeGen/Mips/mips64ext.ll
+++ b/llvm/test/CodeGen/Mips/mips64ext.ll
@@ -1,4 +1,5 @@
-; RUN: llc  < %s -march=mips64el -mcpu=mips64 -mattr=n64 | FileCheck %s 
+; RUN: llc  < %s -march=mips64el -mcpu=mips4 -mattr=n64 | FileCheck %s
+; RUN: llc  < %s -march=mips64el -mcpu=mips64 -mattr=n64 | FileCheck %s
 
 define i64 @zext64_32(i32 %a) nounwind readnone {
 entry: