[mips] Make unalignedload.ll test stricter and easier to modify for MIPS32r6/MIPS64r6

[dsanders]

Summary

• Split into two functions, one to test each struct.
• R0 and R2 must be defined by an lw with a %got reference to the correct symbol.
• Test for $4 (first argument) where appropriate instead of accepting any register.
• Test that the two lbu's are correctly combined into $4

Depends on D3844

[vmedic]

LGTM

test/CodeGen/Mips/unalignedload.ll

-; RUN: llc  < %s -march=mipsel  | FileCheck %s -check-prefix=CHECK-EL
-; RUN: llc  < %s -march=mips    | FileCheck %s -check-prefix=CHECK-EB
+; RUN: llc  < %s -march=mipsel  | FileCheck %s -check-prefix=ALL -check-prefix=CHECK-EL
+; RUN: llc  < %s -march=mips    | FileCheck %s -check-prefix=ALL -check-prefix=CHECK-EB
 %struct.S2 = type { %struct.S1, %struct.S1 }
 %struct.S1 = type { i8, i8 }
 %struct.S4 = type { [7 x i8] }
 
 @s2 = common global %struct.S2 zeroinitializer, align 1
 @s4 = common global %struct.S4 zeroinitializer, align 1
 
-define void @foo1() nounwind {
+define void @bar1() nounwind {
 entry:
-; CHECK-EL-DAG: lbu ${{[0-9]+}}, 2($[[R0:[0-9]+]])
-; CHECK-EL-DAG: lbu ${{[0-9]+}}, 3($[[R0]])
-; CHECK-EL:     jalr
-; CHECK-EL-DAG: lwl $[[R1:[0-9]+]], 3($[[R2:[0-9]+]])
+; ALL-LABEL: bar1:
+
+; ALL-DAG:      lw $[[R0:[0-9]+]], %got(s2)(
+
+; ALL-DAG:      lbu $[[PART1:[0-9]+]], 2($[[R0]])
+; ALL-DAG:      lbu $[[PART2:[0-9]+]], 3($[[R0]])
+
+; CHECK-EL-DAG: sll $[[T0:[0-9]+]], $[[PART2]], 8
+; CHECK-EL-DAG: or  $4, $[[T0]], $[[PART1]]
+
+; CHECK-EB-DAG: sll $[[T0:[0-9]+]], $[[PART1]], 8
+; CHECK-EB-DAG: or  $[[T1:[0-9]+]], $[[T0]], $[[PART2]]
+; CHECK-EB-DAG: sll $4, $[[T1]], 16
+
+  tail call void @foo2(%struct.S1* byval getelementptr inbounds (%struct.S2* @s2, i32 0, i32 1)) nounwind
+  ret void
+}
+
+define void @bar2() nounwind {
+entry:
+; ALL-LABEL: bar2:
+
+; ALL-DAG:      lw $[[R2:[0-9]+]], %got(s4)(
+
+; CHECK-EL-DAG: lwl $[[R1:4]], 3($[[R2]])
 ; CHECK-EL-DAG: lwr $[[R1]], 0($[[R2]])
 
-; CHECK-EB-DAG: lbu ${{[0-9]+}}, 3($[[R0:[0-9]+]])
-; CHECK-EB-DAG: lbu ${{[0-9]+}}, 2($[[R0]])
-; CHECK-EB:     jalr
-; CHECK-EB-DAG: lwl $[[R1:[0-9]+]], 0($[[R2:[0-9]+]])
+; CHECK-EB-DAG: lwl $[[R1:4]], 0($[[R2]])
 ; CHECK-EB-DAG: lwr $[[R1]], 3($[[R2]])
 
-  tail call void @foo2(%struct.S1* byval getelementptr inbounds (%struct.S2* @s2, i32 0, i32 1)) nounwind
   tail call void @foo4(%struct.S4* byval @s4) nounwind
   ret void
 }
 
 declare void @foo2(%struct.S1* byval)
 
 declare void @foo4(%struct.S4* byval)