[mips] Fix delay slot filler so that instructions with register operand $1 are

allowed in branch delay slot.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168131 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/Mips/brdelayslot.ll

@@ -35,3 +35,35 @@ entry:
 
 declare void @foo4(double)
 
+@g2 = external global i32
+@g1 = external global i32
+@g3 = external global i32
+
+; Check that branch delay slot can be filled with an instruction with operand
+; $1.
+;
+; Default:     foo5:
+; Default-NOT: nop
+
+define void @foo5(i32 %a) nounwind {
+entry:
+  %0 = load i32* @g2, align 4
+  %tobool = icmp eq i32 %a, 0
+  br i1 %tobool, label %if.else, label %if.then
+
+if.then:
+  %1 = load i32* @g1, align 4
+  %add = add nsw i32 %1, %0
+  store i32 %add, i32* @g1, align 4
+  br label %if.end
+
+if.else:
+  %2 = load i32* @g3, align 4
+  %sub = sub nsw i32 %2, %0
+  store i32 %sub, i32* @g3, align 4
+  br label %if.end
+
+if.end:
+  ret void
+}
+