Implement ARM32 switch lowering.

tests_lit/llvm2ice_tests/switch-opt.ll

 ; This tests a switch statement, including multiple branches to the
 ; same label which also results in phi instructions with multiple
 ; entries for the same incoming edge.
 
 ; RUN: %p2i -i %s --filetype=obj --disassemble --args -O2 | FileCheck %s
 
+; RUN: %if --need=target_ARM32 --command %p2i --filetype=asm --assemble \
+; RUN:   --disassemble --target arm32 -i %s --args -Om1 --skip-unimplemented \

[jvoung (off chromium), 2015/06/25 21:24:50]

Can you leave a "TODO(jvoung): to switch this to O2, once the phi assignments is
done for ARM"?

[ascull, 2015/06/29 17:00:03]

Done.

+; RUN:   | %if --need=target_ARM32 --command FileCheck --check-prefix ARM32 %s
+
 define i32 @testSwitch(i32 %a) {
 entry:
   switch i32 %a, label %sw.default [
     i32 1, label %sw.epilog
     i32 2, label %sw.epilog
     i32 3, label %sw.epilog
     i32 7, label %sw.bb1
     i32 8, label %sw.bb1
     i32 15, label %sw.bb2
     i32 14, label %sw.bb2
@@ skipping 25 matching lines @@
   switch i32 10, label %sw.default [
     i32 1, label %sw.default
   ]
 
 sw.default:
   ret i32 20
 }
 ; CHECK-LABEL: testSwitchImm
 ; CHECK-NOT: cmp 0x{{[0-9a-f]*}},
 
+; ARM32-LABEL: testSwitchImm
+; ARM32: cmp {{r[0-9]+}}, #1
+; ARM32-NEXT: beq
+; ARM32-NEXT: b
+
 ; Test for correct 64-bit lowering.
 define internal i32 @testSwitch64(i64 %a) {
 entry:
   switch i64 %a, label %sw.default [
     i64 123, label %return
     i64 234, label %sw.bb1
     i64 345, label %sw.bb2
     i64 78187493520, label %sw.bb3
   ]
 
@@ skipping 24 matching lines @@
 ; CHECK-NEXT: je
 ; CHECK: cmp {{.*}},0x159
 ; CHECK-NEXT: jne
 ; CHECK-NEXT: cmp {{.*}},0x0
 ; CHECK-NEXT: je
 ; CHECK: cmp {{.*}},0x34567890
 ; CHECK-NEXT: jne
 ; CHECK-NEXT: cmp {{.*}},0x12
 ; CHECK-NEXT: je
 
+; ARM32-LABEL: testSwitch64
+; ARM32: cmp {{r[0-9]+}}, #123
+; ARM32-NEXT: cmpeq {{r[0-9]+}}, #0
+; ARM32-NEXT: beq
+; ARM32: cmp {{r[0-9]+}}, #234
+; ARM32-NEXT: cmpeq {{r[0-9]+}}, #0
+; ARM32-NEXT: beq
+; ARM32: movw [[REG:r[0-9]+]], #345
+; ARM32-NEXT: cmp {{r[0-9]+}}, [[REG]]
+; ARM32-NEXT: cmpeq {{r[0-9]+}}, #0
+; ARM32-NEXT: beq
+; ARM32: movw [[REG:r[0-9]+]], #30864
+; ARM32-NEXT: movt [[REG]], #13398
+; ARM32-NEXT: cmp {{r[0-9]+}}, [[REG]]
+; ARM32-NEXT: cmpeq {{r[0-9]+}}, #18
+; ARM32-NEXT: beq
+; ARM32-NEXT: b
+
 ; Similar to testSwitchImm, make sure proper addressing modes are
 ; used.  In reality, this is tested by running the output through the
 ; assembler.
 define i32 @testSwitchImm64() {
 entry:
   switch i64 10, label %sw.default [
     i64 1, label %sw.default
   ]
 
 sw.default:
   ret i32 20
 }
 ; CHECK-LABEL: testSwitchImm64
 ; CHECK: cmp {{.*}},0x1
 ; CHECK-NEXT: jne
 ; CHECK-NEXT: cmp {{.*}},0x0
 ; CHECK-NEXT: je
+
+; ARM32-LABEL: testSwitchImm64
+; ARM32: cmp {{r[0-9]+}}, #1
+; ARM32-NEXT: cmpeq {{r[0-9]+}}, #0
+; ARM32-NEXT: beq [[ADDR:[0-9a-f]+]]
+; ARM32-NEXT: b [[ADDR]]
+