Subzero: Basic unconditional branch for Mips.

tests_lit/llvm2ice_tests/uncond_br.ll

Index: tests_lit/llvm2ice_tests/uncond_br.ll
diff --git a/tests_lit/llvm2ice_tests/uncond_br.ll b/tests_lit/llvm2ice_tests/uncond_br.ll
new file mode 100644
index 0000000000000000000000000000000000000000..c3c24831e54f93c0af8a024d32a4bf28e43b43a1
--- /dev/null
+++ b/tests_lit/llvm2ice_tests/uncond_br.ll
@@ -0,0 +1,41 @@
+; TODO(rkotler): Stop skipping unimplemented parts (via --skip-unimplemented)
+; once enough infrastructure is in. Also, switch to --filetype=obj
+; when possible.
+; RUN: %if --need=target_MIPS32 --need=allow_dump \
+; RUN:   --command %p2i --filetype=asm --assemble \
+; RUN:   --disassemble --target mips32 -i %s --args -O2 --skip-unimplemented \
+; RUN:   -allow-externally-defined-symbols \
+; RUN:   | %if --need=target_MIPS32 --need=allow_dump \
+; RUN:   --command FileCheck --check-prefix MIPS32 %s
+
+define internal void @uncond1(i32 %i) {
+  %1 = alloca i8, i32 4, align 4
+  %.bc = bitcast i8* %1 to i32*
+  store i32 %i, i32* %.bc, align 1
+  br label %2
+; <label>:2                                       ; preds = %2, %0

[Jim Stichnoth, 2016/02/23 06:18:51]

I know this was basically auto-generated, but it would be more readable and
probably more reliable if you give this label an actual name, like:

...
  br label %target
target:
...

[rkotlerimgtec, 2016/02/23 23:17:20]

Done.

+  %.bc1 = bitcast i8* %1 to i32*
+  %3 = load i32, i32* %.bc1, align 1
+  %4 = add i32 %3, 1
+  %.bc2 = bitcast i8* %1 to i32*
+  store i32 %4, i32* %.bc2, align 1
+  br label %2
+}
+
+; MIPS32-LABEL: uncond1
+; MIPS32:   b  8 <.Luncond1$__1>

[Jim Stichnoth, 2016/02/23 06:18:51]

Does the "8" refer to a byte offset within the function?  If so, you probably
want to future-proof this because offsets are likely to change once the prolog
is implemented.  E.g.:

; MIPS32: b {{.*}} <.Luncond1$__1>

BTW, I made the comment about providing a trivial definition of Label::getName()
for a MINIMAL build, but I guess that would be a problem here because this lit
test is run in MINIMAL builds...

[rkotlerimgtec, 2016/02/23 23:17:20]

i'm not exactly sure what the 8 means. it's something from the objdump program.
i'm just emitting a branch in assembly to a label.

+; MIPS32: <.Luncond1$__1>:
+; MIPS32: li
+; MIPS32: addu
+; MIPS32: b 8 <.Luncond1$__1>
+

[Jim Stichnoth, 2016/02/23 06:18:51]

Just remove the rest of this.

[rkotlerimgtec, 2016/02/23 23:17:20]

Done.

+define internal i32 @nacl_tp_tdb_offset(i32) {
+entry:
+  ret i32 0
+}
+
+define internal i32 @nacl_tp_tls_offset(i32 %size) {
+entry:
+  %result = sub i32 0, %size
+  ret i32 %result
+}