[MIPS GlobalISel] Select sub

Lower G_USUBO and G_USUBE. Add narrowScalar for G_SUB.
Legalize and select G_SUB for MIPS 32.

Differential Revision: https://reviews.llvm.org/D53416

llvm-svn: 352351

4 files changed, 561 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/Mips/GlobalISel/instruction-select/sub.mir b/llvm/test/CodeGen/Mips/GlobalISel/instruction-select/sub.mir
new file mode 100644
index 00000000000..911073a7f8d
--- /dev/null
+++ b/llvm/test/CodeGen/Mips/GlobalISel/instruction-select/sub.mir
@@ -0,0 +1,31 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -O0 -mtriple=mipsel-linux-gnu -run-pass=instruction-select -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=MIPS32
+--- |
+
+  define void @sub_i32(i32 %x, i32 %y) {entry: ret void}
+
+...
+---
+name:            sub_i32
+alignment:       2
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i32
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:gpr32 = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
+    ; MIPS32: [[SUBu:%[0-9]+]]:gpr32 = SUBu [[COPY]], [[COPY1]]
+    ; MIPS32: $v0 = COPY [[SUBu]]
+    ; MIPS32: RetRA implicit $v0
+    %0:gprb(s32) = COPY $a0
+    %1:gprb(s32) = COPY $a1
+    %2:gprb(s32) = G_SUB %0, %1
+    $v0 = COPY %2(s32)
+    RetRA implicit $v0
+
+...
diff --git a/llvm/test/CodeGen/Mips/GlobalISel/legalizer/sub.mir b/llvm/test/CodeGen/Mips/GlobalISel/legalizer/sub.mir
new file mode 100644
index 00000000000..aabb90705f2
--- /dev/null
+++ b/llvm/test/CodeGen/Mips/GlobalISel/legalizer/sub.mir
@@ -0,0 +1,342 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -O0 -mtriple=mipsel-linux-gnu -run-pass=legalizer -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=MIPS32
+--- |
+
+  define void @sub_i32() {entry: ret void}
+  define void @sub_i8_sext() {entry: ret void}
+  define void @sub_i8_zext() {entry: ret void}
+  define void @sub_i8_aext() {entry: ret void}
+  define void @sub_i16_sext() {entry: ret void}
+  define void @sub_i16_zext() {entry: ret void}
+  define void @sub_i16_aext() {entry: ret void}
+  define void @sub_i64() {entry: ret void}
+  define void @sub_i128() {entry: ret void}
+
+...
+---
+name:            sub_i32
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i32
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY]], [[COPY1]]
+    ; MIPS32: $v0 = COPY [[SUB]](s32)
+    ; MIPS32: RetRA implicit $v0
+    %0:_(s32) = COPY $a0
+    %1:_(s32) = COPY $a1
+    %2:_(s32) = G_SUB %0, %1
+    $v0 = COPY %2(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            sub_i8_sext
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i8_sext
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[COPY2:%[0-9]+]]:_(s32) = COPY [[COPY1]](s32)
+    ; MIPS32: [[COPY3:%[0-9]+]]:_(s32) = COPY [[COPY]](s32)
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY2]], [[COPY3]]
+    ; MIPS32: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 24
+    ; MIPS32: [[COPY4:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; MIPS32: [[SHL:%[0-9]+]]:_(s32) = G_SHL [[COPY4]], [[C]]
+    ; MIPS32: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SHL]], [[C]]
+    ; MIPS32: $v0 = COPY [[ASHR]](s32)
+    ; MIPS32: RetRA implicit $v0
+    %2:_(s32) = COPY $a0
+    %0:_(s8) = G_TRUNC %2(s32)
+    %3:_(s32) = COPY $a1
+    %1:_(s8) = G_TRUNC %3(s32)
+    %4:_(s8) = G_SUB %1, %0
+    %5:_(s32) = G_SEXT %4(s8)
+    $v0 = COPY %5(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            sub_i8_zext
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i8_zext
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[COPY2:%[0-9]+]]:_(s32) = COPY [[COPY1]](s32)
+    ; MIPS32: [[COPY3:%[0-9]+]]:_(s32) = COPY [[COPY]](s32)
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY2]], [[COPY3]]
+    ; MIPS32: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 255
+    ; MIPS32: [[COPY4:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; MIPS32: [[AND:%[0-9]+]]:_(s32) = G_AND [[COPY4]], [[C]]
+    ; MIPS32: $v0 = COPY [[AND]](s32)
+    ; MIPS32: RetRA implicit $v0
+    %2:_(s32) = COPY $a0
+    %0:_(s8) = G_TRUNC %2(s32)
+    %3:_(s32) = COPY $a1
+    %1:_(s8) = G_TRUNC %3(s32)
+    %4:_(s8) = G_SUB %1, %0
+    %5:_(s32) = G_ZEXT %4(s8)
+    $v0 = COPY %5(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            sub_i8_aext
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i8_aext
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[COPY2:%[0-9]+]]:_(s32) = COPY [[COPY1]](s32)
+    ; MIPS32: [[COPY3:%[0-9]+]]:_(s32) = COPY [[COPY]](s32)
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY2]], [[COPY3]]
+    ; MIPS32: [[COPY4:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; MIPS32: $v0 = COPY [[COPY4]](s32)
+    ; MIPS32: RetRA implicit $v0
+    %2:_(s32) = COPY $a0
+    %0:_(s8) = G_TRUNC %2(s32)
+    %3:_(s32) = COPY $a1
+    %1:_(s8) = G_TRUNC %3(s32)
+    %4:_(s8) = G_SUB %1, %0
+    %5:_(s32) = G_ANYEXT %4(s8)
+    $v0 = COPY %5(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            sub_i16_sext
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i16_sext
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[COPY2:%[0-9]+]]:_(s32) = COPY [[COPY1]](s32)
+    ; MIPS32: [[COPY3:%[0-9]+]]:_(s32) = COPY [[COPY]](s32)
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY2]], [[COPY3]]
+    ; MIPS32: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 16
+    ; MIPS32: [[COPY4:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; MIPS32: [[SHL:%[0-9]+]]:_(s32) = G_SHL [[COPY4]], [[C]]
+    ; MIPS32: [[ASHR:%[0-9]+]]:_(s32) = G_ASHR [[SHL]], [[C]]
+    ; MIPS32: $v0 = COPY [[ASHR]](s32)
+    ; MIPS32: RetRA implicit $v0
+    %2:_(s32) = COPY $a0
+    %0:_(s16) = G_TRUNC %2(s32)
+    %3:_(s32) = COPY $a1
+    %1:_(s16) = G_TRUNC %3(s32)
+    %4:_(s16) = G_SUB %1, %0
+    %5:_(s32) = G_SEXT %4(s16)
+    $v0 = COPY %5(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            sub_i16_zext
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i16_zext
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[COPY2:%[0-9]+]]:_(s32) = COPY [[COPY1]](s32)
+    ; MIPS32: [[COPY3:%[0-9]+]]:_(s32) = COPY [[COPY]](s32)
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY2]], [[COPY3]]
+    ; MIPS32: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 65535
+    ; MIPS32: [[COPY4:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; MIPS32: [[AND:%[0-9]+]]:_(s32) = G_AND [[COPY4]], [[C]]
+    ; MIPS32: $v0 = COPY [[AND]](s32)
+    ; MIPS32: RetRA implicit $v0
+    %2:_(s32) = COPY $a0
+    %0:_(s16) = G_TRUNC %2(s32)
+    %3:_(s32) = COPY $a1
+    %1:_(s16) = G_TRUNC %3(s32)
+    %4:_(s16) = G_SUB %1, %0
+    %5:_(s32) = G_ZEXT %4(s16)
+    $v0 = COPY %5(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            sub_i16_aext
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i16_aext
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[COPY2:%[0-9]+]]:_(s32) = COPY [[COPY1]](s32)
+    ; MIPS32: [[COPY3:%[0-9]+]]:_(s32) = COPY [[COPY]](s32)
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY2]], [[COPY3]]
+    ; MIPS32: [[COPY4:%[0-9]+]]:_(s32) = COPY [[SUB]](s32)
+    ; MIPS32: $v0 = COPY [[COPY4]](s32)
+    ; MIPS32: RetRA implicit $v0
+    %2:_(s32) = COPY $a0
+    %0:_(s16) = G_TRUNC %2(s32)
+    %3:_(s32) = COPY $a1
+    %1:_(s16) = G_TRUNC %3(s32)
+    %4:_(s16) = G_SUB %1, %0
+    %5:_(s32) = G_ANYEXT %4(s16)
+    $v0 = COPY %5(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            sub_i64
+alignment:       2
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1, $a2, $a3
+
+    ; MIPS32-LABEL: name: sub_i64
+    ; MIPS32: liveins: $a0, $a1, $a2, $a3
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[COPY2:%[0-9]+]]:_(s32) = COPY $a2
+    ; MIPS32: [[COPY3:%[0-9]+]]:_(s32) = COPY $a3
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[COPY3]], [[COPY1]]
+    ; MIPS32: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ult), [[COPY3]](s32), [[COPY1]]
+    ; MIPS32: [[SUB1:%[0-9]+]]:_(s32) = G_SUB [[COPY2]], [[COPY]]
+    ; MIPS32: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; MIPS32: [[COPY4:%[0-9]+]]:_(s32) = COPY [[ICMP]](s32)
+    ; MIPS32: [[AND:%[0-9]+]]:_(s32) = G_AND [[COPY4]], [[C]]
+    ; MIPS32: [[SUB2:%[0-9]+]]:_(s32) = G_SUB [[SUB1]], [[AND]]
+    ; MIPS32: $v0 = COPY [[SUB2]](s32)
+    ; MIPS32: $v1 = COPY [[SUB]](s32)
+    ; MIPS32: RetRA implicit $v0, implicit $v1
+    %2:_(s32) = COPY $a0
+    %3:_(s32) = COPY $a1
+    %0:_(s64) = G_MERGE_VALUES %3(s32), %2(s32)
+    %4:_(s32) = COPY $a2
+    %5:_(s32) = COPY $a3
+    %1:_(s64) = G_MERGE_VALUES %5(s32), %4(s32)
+    %6:_(s64) = G_SUB %1, %0
+    %7:_(s32), %8:_(s32) = G_UNMERGE_VALUES %6(s64)
+    $v0 = COPY %8(s32)
+    $v1 = COPY %7(s32)
+    RetRA implicit $v0, implicit $v1
+
+...
+---
+name:            sub_i128
+alignment:       2
+tracksRegLiveness: true
+fixedStack:
+  - { id: 0, offset: 28, size: 4, alignment: 4, stack-id: 0, isImmutable: true }
+  - { id: 1, offset: 24, size: 4, alignment: 8, stack-id: 0, isImmutable: true }
+  - { id: 2, offset: 20, size: 4, alignment: 4, stack-id: 0, isImmutable: true }
+  - { id: 3, offset: 16, size: 4, alignment: 8, stack-id: 0, isImmutable: true }
+body:             |
+  bb.1.entry:
+    liveins: $a0, $a1, $a2, $a3
+
+    ; MIPS32-LABEL: name: sub_i128
+    ; MIPS32: liveins: $a0, $a1, $a2, $a3
+    ; MIPS32: [[COPY:%[0-9]+]]:_(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:_(s32) = COPY $a1
+    ; MIPS32: [[COPY2:%[0-9]+]]:_(s32) = COPY $a2
+    ; MIPS32: [[COPY3:%[0-9]+]]:_(s32) = COPY $a3
+    ; MIPS32: [[FRAME_INDEX:%[0-9]+]]:_(p0) = G_FRAME_INDEX %fixed-stack.0
+    ; MIPS32: [[LOAD:%[0-9]+]]:_(s32) = G_LOAD [[FRAME_INDEX]](p0) :: (load 4 from %fixed-stack.0, align 0)
+    ; MIPS32: [[FRAME_INDEX1:%[0-9]+]]:_(p0) = G_FRAME_INDEX %fixed-stack.1
+    ; MIPS32: [[LOAD1:%[0-9]+]]:_(s32) = G_LOAD [[FRAME_INDEX1]](p0) :: (load 4 from %fixed-stack.1, align 0)
+    ; MIPS32: [[FRAME_INDEX2:%[0-9]+]]:_(p0) = G_FRAME_INDEX %fixed-stack.2
+    ; MIPS32: [[LOAD2:%[0-9]+]]:_(s32) = G_LOAD [[FRAME_INDEX2]](p0) :: (load 4 from %fixed-stack.2, align 0)
+    ; MIPS32: [[FRAME_INDEX3:%[0-9]+]]:_(p0) = G_FRAME_INDEX %fixed-stack.3
+    ; MIPS32: [[LOAD3:%[0-9]+]]:_(s32) = G_LOAD [[FRAME_INDEX3]](p0) :: (load 4 from %fixed-stack.3, align 0)
+    ; MIPS32: [[SUB:%[0-9]+]]:_(s32) = G_SUB [[LOAD]], [[COPY]]
+    ; MIPS32: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(ult), [[LOAD]](s32), [[COPY]]
+    ; MIPS32: [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+    ; MIPS32: [[SUB1:%[0-9]+]]:_(s32) = G_SUB [[LOAD1]], [[COPY1]]
+    ; MIPS32: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; MIPS32: [[COPY4:%[0-9]+]]:_(s32) = COPY [[ICMP]](s32)
+    ; MIPS32: [[AND:%[0-9]+]]:_(s32) = G_AND [[COPY4]], [[C]]
+    ; MIPS32: [[SUB2:%[0-9]+]]:_(s32) = G_SUB [[SUB1]], [[AND]]
+    ; MIPS32: [[ICMP1:%[0-9]+]]:_(s32) = G_ICMP intpred(eq), [[LOAD1]](s32), [[COPY1]]
+    ; MIPS32: [[ICMP2:%[0-9]+]]:_(s32) = G_ICMP intpred(ult), [[LOAD1]](s32), [[COPY1]]
+    ; MIPS32: [[COPY5:%[0-9]+]]:_(s32) = COPY [[ICMP]](s32)
+    ; MIPS32: [[COPY6:%[0-9]+]]:_(s32) = COPY [[ICMP2]](s32)
+    ; MIPS32: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; MIPS32: [[COPY7:%[0-9]+]]:_(s32) = COPY [[ICMP1]](s32)
+    ; MIPS32: [[AND1:%[0-9]+]]:_(s32) = G_AND [[COPY7]], [[C1]]
+    ; MIPS32: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[AND1]](s32), [[COPY5]], [[COPY6]]
+    ; MIPS32: [[TRUNC1:%[0-9]+]]:_(s1) = G_TRUNC [[SELECT]](s32)
+    ; MIPS32: [[SUB3:%[0-9]+]]:_(s32) = G_SUB [[LOAD2]], [[COPY2]]
+    ; MIPS32: [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; MIPS32: [[COPY8:%[0-9]+]]:_(s32) = COPY [[SELECT]](s32)
+    ; MIPS32: [[AND2:%[0-9]+]]:_(s32) = G_AND [[COPY8]], [[C2]]
+    ; MIPS32: [[SUB4:%[0-9]+]]:_(s32) = G_SUB [[SUB3]], [[AND2]]
+    ; MIPS32: [[ICMP3:%[0-9]+]]:_(s32) = G_ICMP intpred(eq), [[LOAD2]](s32), [[COPY2]]
+    ; MIPS32: [[ICMP4:%[0-9]+]]:_(s32) = G_ICMP intpred(ult), [[LOAD2]](s32), [[COPY2]]
+    ; MIPS32: [[COPY9:%[0-9]+]]:_(s32) = COPY [[SELECT]](s32)
+    ; MIPS32: [[COPY10:%[0-9]+]]:_(s32) = COPY [[ICMP4]](s32)
+    ; MIPS32: [[C3:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; MIPS32: [[COPY11:%[0-9]+]]:_(s32) = COPY [[ICMP3]](s32)
+    ; MIPS32: [[AND3:%[0-9]+]]:_(s32) = G_AND [[COPY11]], [[C3]]
+    ; MIPS32: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[AND3]](s32), [[COPY9]], [[COPY10]]
+    ; MIPS32: [[SUB5:%[0-9]+]]:_(s32) = G_SUB [[LOAD3]], [[COPY3]]
+    ; MIPS32: [[C4:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+    ; MIPS32: [[COPY12:%[0-9]+]]:_(s32) = COPY [[SELECT1]](s32)
+    ; MIPS32: [[AND4:%[0-9]+]]:_(s32) = G_AND [[COPY12]], [[C4]]
+    ; MIPS32: [[SUB6:%[0-9]+]]:_(s32) = G_SUB [[SUB5]], [[AND4]]
+    ; MIPS32: $v0 = COPY [[SUB]](s32)
+    ; MIPS32: $v1 = COPY [[SUB2]](s32)
+    ; MIPS32: $a0 = COPY [[SUB4]](s32)
+    ; MIPS32: $a1 = COPY [[SUB6]](s32)
+    ; MIPS32: RetRA implicit $v0, implicit $v1, implicit $a0, implicit $a1
+    %2:_(s32) = COPY $a0
+    %3:_(s32) = COPY $a1
+    %4:_(s32) = COPY $a2
+    %5:_(s32) = COPY $a3
+    %0:_(s128) = G_MERGE_VALUES %2(s32), %3(s32), %4(s32), %5(s32)
+    %10:_(p0) = G_FRAME_INDEX %fixed-stack.3
+    %6:_(s32) = G_LOAD %10(p0) :: (load 4 from %fixed-stack.3, align 0)
+    %11:_(p0) = G_FRAME_INDEX %fixed-stack.2
+    %7:_(s32) = G_LOAD %11(p0) :: (load 4 from %fixed-stack.2, align 0)
+    %12:_(p0) = G_FRAME_INDEX %fixed-stack.1
+    %8:_(s32) = G_LOAD %12(p0) :: (load 4 from %fixed-stack.1, align 0)
+    %13:_(p0) = G_FRAME_INDEX %fixed-stack.0
+    %9:_(s32) = G_LOAD %13(p0) :: (load 4 from %fixed-stack.0, align 0)
+    %1:_(s128) = G_MERGE_VALUES %6(s32), %7(s32), %8(s32), %9(s32)
+    %14:_(s128) = G_SUB %1, %0
+    %15:_(s32), %16:_(s32), %17:_(s32), %18:_(s32) = G_UNMERGE_VALUES %14(s128)
+    $v0 = COPY %15(s32)
+    $v1 = COPY %16(s32)
+    $a0 = COPY %17(s32)
+    $a1 = COPY %18(s32)
+    RetRA implicit $v0, implicit $v1, implicit $a0, implicit $a1
+
+...
diff --git a/llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/sub.ll b/llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/sub.ll
new file mode 100644
index 00000000000..e97fed213b0
--- /dev/null
+++ b/llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/sub.ll
@@ -0,0 +1,158 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc  -O0 -mtriple=mipsel-linux-gnu -global-isel  -verify-machineinstrs %s -o -| FileCheck %s -check-prefixes=MIPS32
+
+define i32 @sub_i32(i32 %x, i32 %y) {
+; MIPS32-LABEL: sub_i32:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    subu $2, $4, $5
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %z = sub i32 %x, %y
+  ret i32 %z
+}
+
+define signext i8 @sub_i8_sext(i8 signext %a, i8 signext %b) {
+; MIPS32-LABEL: sub_i8_sext:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    subu $4, $5, $4
+; MIPS32-NEXT:    sll $4, $4, 24
+; MIPS32-NEXT:    sra $2, $4, 24
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %sub = sub i8 %b, %a
+  ret i8 %sub
+}
+
+define zeroext i8 @sub_i8_zext(i8 zeroext %a, i8 zeroext %b) {
+; MIPS32-LABEL: sub_i8_zext:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    subu $4, $5, $4
+; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $5, 255
+; MIPS32-NEXT:    and $2, $4, $5
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %sub = sub i8 %b, %a
+  ret i8 %sub
+}
+
+define i8 @sub_i8_aext(i8 %a, i8 %b) {
+; MIPS32-LABEL: sub_i8_aext:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    subu $2, $5, $4
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %sub = sub i8 %b, %a
+  ret i8 %sub
+}
+
+define signext i16 @sub_i16_sext(i16 signext %a, i16 signext %b) {
+; MIPS32-LABEL: sub_i16_sext:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    subu $4, $5, $4
+; MIPS32-NEXT:    sll $4, $4, 16
+; MIPS32-NEXT:    sra $2, $4, 16
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %sub = sub i16 %b, %a
+  ret i16 %sub
+}
+
+define zeroext i16 @sub_i16_zext(i16 zeroext %a, i16 zeroext %b) {
+; MIPS32-LABEL: sub_i16_zext:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    subu $4, $5, $4
+; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $5, 65535
+; MIPS32-NEXT:    and $2, $4, $5
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %sub = sub i16 %b, %a
+  ret i16 %sub
+}
+
+define i16 @sub_i16_aext(i16 %a, i16 %b) {
+; MIPS32-LABEL: sub_i16_aext:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    subu $2, $5, $4
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %sub = sub i16 %b, %a
+  ret i16 %sub
+}
+
+define i64 @sub_i64(i64 %a, i64 %b) {
+; MIPS32-LABEL: sub_i64:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    subu $2, $6, $4
+; MIPS32-NEXT:    sltu $4, $6, $4
+; MIPS32-NEXT:    subu $5, $7, $5
+; MIPS32-NEXT:    lui $6, 0
+; MIPS32-NEXT:    ori $6, $6, 1
+; MIPS32-NEXT:    and $4, $4, $6
+; MIPS32-NEXT:    subu $3, $5, $4
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %sub = sub i64 %b, %a
+  ret i64 %sub
+}
+
+define i128 @sub_i128(i128 %a, i128 %b) {
+; MIPS32-LABEL: sub_i128:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    addiu $1, $sp, 16
+; MIPS32-NEXT:    lw $1, 0($1)
+; MIPS32-NEXT:    addiu $2, $sp, 20
+; MIPS32-NEXT:    lw $2, 0($2)
+; MIPS32-NEXT:    addiu $3, $sp, 24
+; MIPS32-NEXT:    lw $3, 0($3)
+; MIPS32-NEXT:    addiu $8, $sp, 28
+; MIPS32-NEXT:    lw $8, 0($8)
+; MIPS32-NEXT:    subu $9, $1, $4
+; MIPS32-NEXT:    sltu $1, $1, $4
+; MIPS32-NEXT:    subu $4, $2, $5
+; MIPS32-NEXT:    lui $10, 0
+; MIPS32-NEXT:    ori $10, $10, 1
+; MIPS32-NEXT:    and $10, $1, $10
+; MIPS32-NEXT:    subu $4, $4, $10
+; MIPS32-NEXT:    xor $10, $2, $5
+; MIPS32-NEXT:    sltiu $10, $10, 1
+; MIPS32-NEXT:    sltu $2, $2, $5
+; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $5, 1
+; MIPS32-NEXT:    and $5, $10, $5
+; MIPS32-NEXT:    movn $2, $1, $5
+; MIPS32-NEXT:    subu $1, $3, $6
+; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $5, 1
+; MIPS32-NEXT:    and $5, $2, $5
+; MIPS32-NEXT:    subu $1, $1, $5
+; MIPS32-NEXT:    xor $5, $3, $6
+; MIPS32-NEXT:    sltiu $5, $5, 1
+; MIPS32-NEXT:    sltu $3, $3, $6
+; MIPS32-NEXT:    lui $6, 0
+; MIPS32-NEXT:    ori $6, $6, 1
+; MIPS32-NEXT:    and $5, $5, $6
+; MIPS32-NEXT:    movn $3, $2, $5
+; MIPS32-NEXT:    subu $2, $8, $7
+; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $5, 1
+; MIPS32-NEXT:    and $3, $3, $5
+; MIPS32-NEXT:    subu $5, $2, $3
+; MIPS32-NEXT:    move $2, $9
+; MIPS32-NEXT:    move $3, $4
+; MIPS32-NEXT:    move $4, $1
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  %sub = sub i128 %b, %a
+  ret i128 %sub
+}
diff --git a/llvm/test/CodeGen/Mips/GlobalISel/regbankselect/sub.mir b/llvm/test/CodeGen/Mips/GlobalISel/regbankselect/sub.mir
new file mode 100644
index 00000000000..487024783e6
--- /dev/null
+++ b/llvm/test/CodeGen/Mips/GlobalISel/regbankselect/sub.mir
@@ -0,0 +1,30 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -O0 -mtriple=mipsel-linux-gnu -run-pass=regbankselect -verify-machineinstrs %s -o - | FileCheck %s -check-prefixes=MIPS32
+--- |
+
+  define void @sub_i32(i32 %x, i32 %y) {entry: ret void}
+
+...
+---
+name:            sub_i32
+alignment:       2
+legalized:       true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $a0, $a1
+
+    ; MIPS32-LABEL: name: sub_i32
+    ; MIPS32: liveins: $a0, $a1
+    ; MIPS32: [[COPY:%[0-9]+]]:gprb(s32) = COPY $a0
+    ; MIPS32: [[COPY1:%[0-9]+]]:gprb(s32) = COPY $a1
+    ; MIPS32: [[SUB:%[0-9]+]]:gprb(s32) = G_SUB [[COPY]], [[COPY1]]
+    ; MIPS32: $v0 = COPY [[SUB]](s32)
+    ; MIPS32: RetRA implicit $v0
+    %0:_(s32) = COPY $a0
+    %1:_(s32) = COPY $a1
+    %2:_(s32) = G_SUB %0, %1
+    $v0 = COPY %2(s32)
+    RetRA implicit $v0
+
+...