[MIPS GlobalISel] Improve selection of constants

Certain 32 bit constants can be generated with a single instruction
instead of two. Implement materialize32BitImm function for MIPS32.

Differential Revision: https://reviews.llvm.org/D59369

llvm-svn: 356238

llvm/lib/Target/Mips/MipsInstructionSelector.cpp

@@ -36,6 +36,8 @@ public:
 
 private:
   bool selectImpl(MachineInstr &I, CodeGenCoverage &CoverageInfo) const;
+  bool materialize32BitImm(unsigned DestReg, APInt Imm,
+                           MachineIRBuilder &B) const;
 
   const MipsTargetMachine &TM;
   const MipsSubtarget &STI;
@@ -90,6 +92,40 @@ static bool selectCopy(MachineInstr &I, const TargetInstrInfo &TII,
   return true;
 }
 
+bool MipsInstructionSelector::materialize32BitImm(unsigned DestReg, APInt Imm,
+                                                  MachineIRBuilder &B) const {
+  assert(Imm.getBitWidth() == 32 && "Unsupported immediate size.");
+  // Ori zero extends immediate. Used for values with zeros in high 16 bits.
+  if (Imm.getHiBits(16).isNullValue()) {
+    MachineInstr *Inst = B.buildInstr(Mips::ORi, {DestReg}, {Mips::ZERO})
+                             .addImm(Imm.getLoBits(16).getLimitedValue());
+    return constrainSelectedInstRegOperands(*Inst, TII, TRI, RBI);
+  }
+  // Lui places immediate in high 16 bits and sets low 16 bits to zero.
+  if (Imm.getLoBits(16).isNullValue()) {
+    MachineInstr *Inst = B.buildInstr(Mips::LUi, {DestReg}, {})
+                             .addImm(Imm.getHiBits(16).getLimitedValue());
+    return constrainSelectedInstRegOperands(*Inst, TII, TRI, RBI);
+  }
+  // ADDiu sign extends immediate. Used for values with 1s in high 17 bits.
+  if (Imm.isSignedIntN(16)) {
+    MachineInstr *Inst = B.buildInstr(Mips::ADDiu, {DestReg}, {Mips::ZERO})
+                             .addImm(Imm.getLoBits(16).getLimitedValue());
+    return constrainSelectedInstRegOperands(*Inst, TII, TRI, RBI);
+  }
+  // Values that cannot be materialized with single immediate instruction.
+  unsigned LUiReg = B.getMRI()->createVirtualRegister(&Mips::GPR32RegClass);
+  MachineInstr *LUi = B.buildInstr(Mips::LUi, {LUiReg}, {})
+                          .addImm(Imm.getHiBits(16).getLimitedValue());
+  MachineInstr *ORi = B.buildInstr(Mips::ORi, {DestReg}, {LUiReg})
+                          .addImm(Imm.getLoBits(16).getLimitedValue());
+  if (!constrainSelectedInstRegOperands(*LUi, TII, TRI, RBI))
+    return false;
+  if (!constrainSelectedInstRegOperands(*ORi, TII, TRI, RBI))
+    return false;
+  return true;
+}
+
 /// Returning Opc indicates that we failed to select MIPS instruction opcode.
 static unsigned selectLoadStoreOpCode(unsigned Opc, unsigned MemSizeInBytes) {
   if (Opc == TargetOpcode::G_STORE)
@@ -266,22 +302,9 @@ bool MipsInstructionSelector::select(MachineInstr &I,
     break;
   }
   case G_CONSTANT: {
-    int Imm = I.getOperand(1).getCImm()->getValue().getLimitedValue();
+    MachineIRBuilder B(I);
-    unsigned LUiReg = MRI.createVirtualRegister(&Mips::GPR32RegClass);
+    if (!materialize32BitImm(I.getOperand(0).getReg(),
-    MachineInstr *LUi, *ORi;
+                             I.getOperand(1).getCImm()->getValue(), B))
-
-    LUi = BuildMI(MBB, I, I.getDebugLoc(), TII.get(Mips::LUi))
-              .addDef(LUiReg)
-              .addImm(Imm >> 16);
-
-    ORi = BuildMI(MBB, I, I.getDebugLoc(), TII.get(Mips::ORi))
-              .addDef(I.getOperand(0).getReg())
-              .addUse(LUiReg)
-              .addImm(Imm & 0xFFFF);
-
-    if (!constrainSelectedInstRegOperands(*LUi, TII, TRI, RBI))
-      return false;
-    if (!constrainSelectedInstRegOperands(*ORi, TII, TRI, RBI))
       return false;
 
     I.eraseFromParent();

llvm/test/CodeGen/Mips/GlobalISel/instruction-select/branch.mir

@@ -71,8 +71,7 @@ body:             |
   ; MIPS32:   [[COPY:%[0-9]+]]:gpr32 = COPY $a0
   ; MIPS32:   [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
   ; MIPS32:   [[COPY2:%[0-9]+]]:gpr32 = COPY $a2
-  ; MIPS32:   [[LUi:%[0-9]+]]:gpr32 = LUi 0
+  ; MIPS32:   [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-  ; MIPS32:   [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
   ; MIPS32:   [[AND:%[0-9]+]]:gpr32 = AND [[COPY]], [[ORi]]
   ; MIPS32:   BNE [[AND]], $zero, %bb.1, implicit-def $at
   ; MIPS32:   J %bb.2, implicit-def $at

llvm/test/CodeGen/Mips/GlobalISel/instruction-select/constants.mir

@@ -0,0 +1,80 @@
+# 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 @_0xABCD0000() {entry: ret void}
+  define void @_0x00008000() {entry: ret void}
+  define void @_0xFFFFFFF6() {entry: ret void}
+  define void @_0x0A0B0C0D() {entry: ret void}
+
+...
+---
+name:            _0xABCD0000
+alignment:       2
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    ; MIPS32-LABEL: name: _0xABCD0000
+    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 43981
+    ; MIPS32: $v0 = COPY [[LUi]]
+    ; MIPS32: RetRA implicit $v0
+    %0:gprb(s32) = G_CONSTANT i32 -1412628480
+    $v0 = COPY %0(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            _0x00008000
+alignment:       2
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    ; MIPS32-LABEL: name: _0x00008000
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 32768
+    ; MIPS32: $v0 = COPY [[ORi]]
+    ; MIPS32: RetRA implicit $v0
+    %0:gprb(s32) = G_CONSTANT i32 32768
+    $v0 = COPY %0(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            _0xFFFFFFF6
+alignment:       2
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    ; MIPS32-LABEL: name: _0xFFFFFFF6
+    ; MIPS32: [[ADDiu:%[0-9]+]]:gpr32 = ADDiu $zero, 65526
+    ; MIPS32: $v0 = COPY [[ADDiu]]
+    ; MIPS32: RetRA implicit $v0
+    %0:gprb(s32) = G_CONSTANT i32 -10
+    $v0 = COPY %0(s32)
+    RetRA implicit $v0
+
+...
+---
+name:            _0x0A0B0C0D
+alignment:       2
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    ; MIPS32-LABEL: name: _0x0A0B0C0D
+    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 2571
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 3085
+    ; MIPS32: $v0 = COPY [[ORi]]
+    ; MIPS32: RetRA implicit $v0
+    %0:gprb(s32) = G_CONSTANT i32 168496141
+    $v0 = COPY %0(s32)
+    RetRA implicit $v0
+
+...
+

llvm/test/CodeGen/Mips/GlobalISel/instruction-select/gloal_address.mir

@@ -21,8 +21,7 @@ body:             |
     ; MIPS32: [[ADDiu:%[0-9]+]]:gpr32 = ADDiu [[LUi]], target-flags(mips-abs-lo) @.str
     ; MIPS32: [[LUi1:%[0-9]+]]:gpr32 = LUi 18838
     ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi1]], 722
-    ; MIPS32: [[LUi2:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi1:%[0-9]+]]:gpr32 = ORi $zero, 0
-    ; MIPS32: [[ORi1:%[0-9]+]]:gpr32 = ORi [[LUi2]], 0
     ; MIPS32: ADJCALLSTACKDOWN 16, 0, implicit-def $sp, implicit $sp
     ; MIPS32: $a0 = COPY [[ADDiu]]
     ; MIPS32: $a1 = COPY [[ORi]]

llvm/test/CodeGen/Mips/GlobalISel/instruction-select/icmp.mir

@@ -30,8 +30,7 @@ body:             |
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[XOR:%[0-9]+]]:gpr32 = XOR [[COPY]], [[COPY1]]
     ; MIPS32: [[SLTiu:%[0-9]+]]:gpr32 = SLTiu [[XOR]], 1
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[SLTiu]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -61,8 +60,7 @@ body:             |
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[XOR:%[0-9]+]]:gpr32 = XOR [[COPY]], [[COPY1]]
     ; MIPS32: [[SLTu:%[0-9]+]]:gpr32 = SLTu $zero, [[XOR]]
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[SLTu]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -91,8 +89,7 @@ body:             |
     ; MIPS32: [[COPY:%[0-9]+]]:gpr32 = COPY $a0
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[SLT:%[0-9]+]]:gpr32 = SLT [[COPY1]], [[COPY]]
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[SLT]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -122,8 +119,7 @@ body:             |
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[SLT:%[0-9]+]]:gpr32 = SLT [[COPY]], [[COPY1]]
     ; MIPS32: [[XORi:%[0-9]+]]:gpr32 = XORi [[SLT]], 1
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[XORi]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -152,8 +148,7 @@ body:             |
     ; MIPS32: [[COPY:%[0-9]+]]:gpr32 = COPY $a0
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[SLT:%[0-9]+]]:gpr32 = SLT [[COPY]], [[COPY1]]
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[SLT]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -183,8 +178,7 @@ body:             |
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[SLT:%[0-9]+]]:gpr32 = SLT [[COPY1]], [[COPY]]
     ; MIPS32: [[XORi:%[0-9]+]]:gpr32 = XORi [[SLT]], 1
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[XORi]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -213,8 +207,7 @@ body:             |
     ; MIPS32: [[COPY:%[0-9]+]]:gpr32 = COPY $a0
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[SLTu:%[0-9]+]]:gpr32 = SLTu [[COPY1]], [[COPY]]
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[SLTu]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -244,8 +237,7 @@ body:             |
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[SLTu:%[0-9]+]]:gpr32 = SLTu [[COPY]], [[COPY1]]
     ; MIPS32: [[XORi:%[0-9]+]]:gpr32 = XORi [[SLTu]], 1
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[XORi]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -274,8 +266,7 @@ body:             |
     ; MIPS32: [[COPY:%[0-9]+]]:gpr32 = COPY $a0
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[SLTu:%[0-9]+]]:gpr32 = SLTu [[COPY]], [[COPY1]]
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[SLTu]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0
@@ -305,8 +296,7 @@ body:             |
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[SLTu:%[0-9]+]]:gpr32 = SLTu [[COPY1]], [[COPY]]
     ; MIPS32: [[XORi:%[0-9]+]]:gpr32 = XORi [[SLTu]], 1
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[XORi]], [[ORi]]
     ; MIPS32: $v0 = COPY [[AND]]
     ; MIPS32: RetRA implicit $v0

llvm/test/CodeGen/Mips/GlobalISel/instruction-select/mul.mir

@@ -49,12 +49,10 @@ body:             |
     ; MIPS32: [[MUL:%[0-9]+]]:gpr32 = MUL [[COPY]], [[COPY1]], implicit-def dead $hi0, implicit-def dead $lo0
     ; MIPS32: [[PseudoMULTu:%[0-9]+]]:acc64 = PseudoMULTu [[COPY]], [[COPY1]]
     ; MIPS32: [[PseudoMFHI:%[0-9]+]]:gpr32 = PseudoMFHI [[PseudoMULTu]]
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 0
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 0
     ; MIPS32: [[XOR:%[0-9]+]]:gpr32 = XOR [[PseudoMFHI]], [[ORi]]
     ; MIPS32: [[SLTu:%[0-9]+]]:gpr32 = SLTu $zero, [[XOR]]
-    ; MIPS32: [[LUi1:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi1:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi1:%[0-9]+]]:gpr32 = ORi [[LUi1]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[SLTu]], [[ORi1]]
     ; MIPS32: SB [[AND]], [[COPY3]], 0 :: (store 1 into %ir.pcarry_flag)
     ; MIPS32: SW [[MUL]], [[COPY2]], 0 :: (store 4 into %ir.pmul)

llvm/test/CodeGen/Mips/GlobalISel/instruction-select/phi.mir

@@ -32,8 +32,7 @@ body:             |
   ; MIPS32:   [[COPY:%[0-9]+]]:gpr32 = COPY $a0
   ; MIPS32:   [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
   ; MIPS32:   [[COPY2:%[0-9]+]]:gpr32 = COPY $a2
-  ; MIPS32:   [[LUi:%[0-9]+]]:gpr32 = LUi 0
+  ; MIPS32:   [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-  ; MIPS32:   [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
   ; MIPS32:   [[AND:%[0-9]+]]:gpr32 = AND [[COPY]], [[ORi]]
   ; MIPS32:   BNE [[AND]], $zero, %bb.1, implicit-def $at
   ; MIPS32:   J %bb.2, implicit-def $at

llvm/test/CodeGen/Mips/GlobalISel/instruction-select/select.mir

@@ -21,8 +21,7 @@ body:             |
     ; MIPS32: [[COPY:%[0-9]+]]:gpr32 = COPY $a0
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[COPY2:%[0-9]+]]:gpr32 = COPY $a2
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[COPY]], [[ORi]]
     ; MIPS32: [[MOVN_I_I:%[0-9]+]]:gpr32 = MOVN_I_I [[COPY1]], [[AND]], [[COPY2]]
     ; MIPS32: $v0 = COPY [[MOVN_I_I]]
@@ -53,8 +52,7 @@ body:             |
     ; MIPS32: [[COPY:%[0-9]+]]:gpr32 = COPY $a0
     ; MIPS32: [[COPY1:%[0-9]+]]:gpr32 = COPY $a1
     ; MIPS32: [[COPY2:%[0-9]+]]:gpr32 = COPY $a2
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 1
     ; MIPS32: [[AND:%[0-9]+]]:gpr32 = AND [[COPY]], [[ORi]]
     ; MIPS32: [[MOVN_I_I:%[0-9]+]]:gpr32 = MOVN_I_I [[COPY1]], [[AND]], [[COPY2]]
     ; MIPS32: $v0 = COPY [[MOVN_I_I]]

llvm/test/CodeGen/Mips/GlobalISel/instruction-select/stack_args.mir

@@ -32,8 +32,7 @@ body:             |
     ; MIPS32: $a2 = COPY [[COPY2]]
     ; MIPS32: $a3 = COPY [[COPY3]]
     ; MIPS32: [[COPY4:%[0-9]+]]:gpr32 = COPY $sp
-    ; MIPS32: [[LUi:%[0-9]+]]:gpr32 = LUi 0
+    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi $zero, 1
-    ; MIPS32: [[ORi:%[0-9]+]]:gpr32 = ORi [[LUi]], 16
     ; MIPS32: [[ADDu:%[0-9]+]]:gpr32 = ADDu [[COPY4]], [[ORi]]
     ; MIPS32: SW [[LW]], [[ADDu]], 0 :: (store 4 into stack + 16)
     ; MIPS32: JAL @f, csr_o32, implicit-def $ra, implicit-def $sp, implicit $a0, implicit $a1, implicit $a2, implicit $a3, implicit-def $v0

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/add.ll

@@ -28,8 +28,7 @@ define zeroext i8 @add_i8_zext(i8 zeroext %a, i8 zeroext %b) {
 ; MIPS32-LABEL: add_i8_zext:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    addu $4, $5, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 255
-; MIPS32-NEXT:    ori $5, $5, 255
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -66,8 +65,7 @@ define zeroext i16 @add_i16_zext(i16 zeroext %a, i16 zeroext %b) {
 ; MIPS32-LABEL: add_i16_zext:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    addu $4, $5, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 65535
-; MIPS32-NEXT:    ori $5, $5, 65535
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -90,17 +88,14 @@ entry:
 define i64 @add_i64(i64 %a, i64 %b) {
 ; MIPS32-LABEL: add_i64:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 0
-; MIPS32-NEXT:    ori $1, $1, 0
 ; MIPS32-NEXT:    addu $4, $6, $4
-; MIPS32-NEXT:    lui $2, 0
+; MIPS32-NEXT:    ori $2, $zero, 1
-; MIPS32-NEXT:    ori $2, $2, 1
 ; MIPS32-NEXT:    and $1, $1, $2
 ; MIPS32-NEXT:    addu $1, $4, $1
 ; MIPS32-NEXT:    sltu $2, $1, $6
 ; MIPS32-NEXT:    addu $4, $7, $5
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $2, $5
 ; MIPS32-NEXT:    addu $3, $4, $2
 ; MIPS32-NEXT:    move $2, $1
@@ -124,29 +119,24 @@ define i128 @add_i128(i128 %a, i128 %b) {
 ; MIPS32-NEXT:    lw $3, 0($3)
 ; MIPS32-NEXT:    addiu $8, $sp, 36
 ; MIPS32-NEXT:    lw $8, 0($8)
-; MIPS32-NEXT:    lui $9, 0
+; MIPS32-NEXT:    ori $9, $zero, 0
-; MIPS32-NEXT:    ori $9, $9, 0
 ; MIPS32-NEXT:    addu $4, $1, $4
-; MIPS32-NEXT:    lui $10, 0
+; MIPS32-NEXT:    ori $10, $zero, 1
-; MIPS32-NEXT:    ori $10, $10, 1
 ; MIPS32-NEXT:    and $9, $9, $10
 ; MIPS32-NEXT:    addu $4, $4, $9
 ; MIPS32-NEXT:    sltu $1, $4, $1
 ; MIPS32-NEXT:    addu $5, $2, $5
-; MIPS32-NEXT:    lui $9, 0
+; MIPS32-NEXT:    ori $9, $zero, 1
-; MIPS32-NEXT:    ori $9, $9, 1
 ; MIPS32-NEXT:    and $1, $1, $9
 ; MIPS32-NEXT:    addu $1, $5, $1
 ; MIPS32-NEXT:    sltu $2, $1, $2
 ; MIPS32-NEXT:    addu $5, $3, $6
-; MIPS32-NEXT:    lui $6, 0
+; MIPS32-NEXT:    ori $6, $zero, 1
-; MIPS32-NEXT:    ori $6, $6, 1
 ; MIPS32-NEXT:    and $2, $2, $6
 ; MIPS32-NEXT:    addu $2, $5, $2
 ; MIPS32-NEXT:    sltu $3, $2, $3
 ; MIPS32-NEXT:    addu $5, $8, $7
-; MIPS32-NEXT:    lui $6, 0
+; MIPS32-NEXT:    ori $6, $zero, 1
-; MIPS32-NEXT:    ori $6, $6, 1
 ; MIPS32-NEXT:    and $3, $3, $6
 ; MIPS32-NEXT:    addu $5, $5, $3
 ; MIPS32-NEXT:    sw $2, 4($sp) # 4-byte Folded Spill
@@ -167,8 +157,7 @@ define void @uadd_with_overflow(i32 %lhs, i32 %rhs, i32* %padd, i1* %pcarry_flag
 ; MIPS32:       # %bb.0:
 ; MIPS32-NEXT:    addu $4, $4, $5
 ; MIPS32-NEXT:    sltu $5, $4, $5
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $5, $1
 ; MIPS32-NEXT:    sb $1, 0($7)
 ; MIPS32-NEXT:    sw $4, 0($6)

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/branch.ll

@@ -30,8 +30,7 @@ define i32 @Conditional_branch(i1 %cond, i32 %a, i32 %b) {
 ; MIPS32:       # %bb.0:
 ; MIPS32-NEXT:    addiu $sp, $sp, -8
 ; MIPS32-NEXT:    .cfi_def_cfa_offset 8
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    sw $5, 4($sp) # 4-byte Folded Spill
 ; MIPS32-NEXT:    sw $6, 0($sp) # 4-byte Folded Spill

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/constants.ll

@@ -4,10 +4,8 @@
 define i64 @any_i64() {
 ; MIPS32-LABEL: any_i64:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $2, $zero, 0
-; MIPS32-NEXT:    ori $2, $1, 0
+; MIPS32-NEXT:    lui $3, 32768
-; MIPS32-NEXT:    lui $1, 32768
-; MIPS32-NEXT:    ori $3, $1, 0
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
 entry:
@@ -17,8 +15,7 @@ entry:
 define i32 @any_i32() {
 ; MIPS32-LABEL: any_i32:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 32768
+; MIPS32-NEXT:    lui $2, 32768
-; MIPS32-NEXT:    ori $2, $1, 0
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
 entry:
@@ -28,8 +25,7 @@ entry:
 define signext i16 @signed_i16() {
 ; MIPS32-LABEL: signed_i16:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 65535
+; MIPS32-NEXT:    addiu $1, $zero, 32768
-; MIPS32-NEXT:    ori $1, $1, 32768
 ; MIPS32-NEXT:    sll $1, $1, 16
 ; MIPS32-NEXT:    sra $2, $1, 16
 ; MIPS32-NEXT:    jr $ra
@@ -41,8 +37,7 @@ entry:
 define signext i8 @signed_i8() {
 ; MIPS32-LABEL: signed_i8:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 65535
+; MIPS32-NEXT:    addiu $1, $zero, 65408
-; MIPS32-NEXT:    ori $1, $1, 65408
 ; MIPS32-NEXT:    sll $1, $1, 24
 ; MIPS32-NEXT:    sra $2, $1, 24
 ; MIPS32-NEXT:    jr $ra
@@ -54,10 +49,8 @@ entry:
 define zeroext i16 @unsigned_i16() {
 ; MIPS32-LABEL: unsigned_i16:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 65535
+; MIPS32-NEXT:    addiu $1, $zero, 32768
-; MIPS32-NEXT:    ori $1, $1, 32768
+; MIPS32-NEXT:    ori $2, $zero, 65535
-; MIPS32-NEXT:    lui $2, 0
-; MIPS32-NEXT:    ori $2, $2, 65535
 ; MIPS32-NEXT:    and $2, $1, $2
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -68,10 +61,8 @@ entry:
 define zeroext i8 @unsigned_i8() {
 ; MIPS32-LABEL: unsigned_i8:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 65535
+; MIPS32-NEXT:    addiu $1, $zero, 65408
-; MIPS32-NEXT:    ori $1, $1, 65408
+; MIPS32-NEXT:    ori $2, $zero, 255
-; MIPS32-NEXT:    lui $2, 0
-; MIPS32-NEXT:    ori $2, $2, 255
 ; MIPS32-NEXT:    and $2, $1, $2
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -82,10 +73,8 @@ entry:
 define zeroext i1 @i1_true() {
 ; MIPS32-LABEL: i1_true:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 65535
+; MIPS32-NEXT:    addiu $1, $zero, 65535
-; MIPS32-NEXT:    ori $1, $1, 65535
+; MIPS32-NEXT:    ori $2, $zero, 1
-; MIPS32-NEXT:    lui $2, 0
-; MIPS32-NEXT:    ori $2, $2, 1
 ; MIPS32-NEXT:    and $2, $1, $2
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -96,13 +85,52 @@ entry:
 define zeroext i1 @i1_false() {
 ; MIPS32-LABEL: i1_false:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 0
-; MIPS32-NEXT:    ori $1, $1, 0
+; MIPS32-NEXT:    ori $2, $zero, 1
-; MIPS32-NEXT:    lui $2, 0
-; MIPS32-NEXT:    ori $2, $2, 1
 ; MIPS32-NEXT:    and $2, $1, $2
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
 entry:
   ret i1 false
 }
+
+define i32 @_0xABCD0000() {
+; MIPS32-LABEL: _0xABCD0000:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    lui $2, 43981
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  ret i32 -1412628480
+}
+
+define i32 @_0x00008000() {
+; MIPS32-LABEL: _0x00008000:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    ori $2, $zero, 32768
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  ret i32 32768
+}
+
+define i32 @_0xFFFFFFF6() {
+; MIPS32-LABEL: _0xFFFFFFF6:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    addiu $2, $zero, 65526
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  ret i32 -10
+}
+
+define i32 @_0x0A0B0C0D() {
+; MIPS32-LABEL: _0x0A0B0C0D:
+; MIPS32:       # %bb.0: # %entry
+; MIPS32-NEXT:    lui $1, 2571
+; MIPS32-NEXT:    ori $2, $1, 3085
+; MIPS32-NEXT:    jr $ra
+; MIPS32-NEXT:    nop
+entry:
+  ret i32 168496141
+}

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/global_address.ll

@@ -14,8 +14,7 @@ define i32 @main() {
 ; MIPS32-NEXT:    addiu $4, $1, %lo($.str)
 ; MIPS32-NEXT:    lui $1, 18838
 ; MIPS32-NEXT:    ori $5, $1, 722
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $2, $zero, 0
-; MIPS32-NEXT:    ori $2, $1, 0
 ; MIPS32-NEXT:    sw $2, 16($sp) # 4-byte Folded Spill
 ; MIPS32-NEXT:    jal printf
 ; MIPS32-NEXT:    nop

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/icmp.ll

@@ -6,8 +6,7 @@ define i32 @eq(i32 %a, i32 %b){
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    xor $4, $4, $5
 ; MIPS32-NEXT:    sltiu $4, $4, 1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -22,8 +21,7 @@ define i32 @ne(i32 %a, i32 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    xor $4, $4, $5
 ; MIPS32-NEXT:    sltu $4, $zero, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -37,8 +35,7 @@ define i32 @sgt(i32 %a, i32 %b) {
 ; MIPS32-LABEL: sgt:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    slt $4, $5, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -53,8 +50,7 @@ define i32 @sge(i32 %a, i32 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    slt $4, $4, $5
 ; MIPS32-NEXT:    xori $4, $4, 1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -68,8 +64,7 @@ define i32 @slt(i32 %a, i32 %b) {
 ; MIPS32-LABEL: slt:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    slt $4, $4, $5
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -84,8 +79,7 @@ define i32 @sle(i32 %a, i32 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    slt $4, $5, $4
 ; MIPS32-NEXT:    xori $4, $4, 1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -99,8 +93,7 @@ define i32 @ugt(i32 %a, i32 %b) {
 ; MIPS32-LABEL: ugt:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    sltu $4, $5, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -115,8 +108,7 @@ define i32 @uge(i32 %a, i32 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    sltu $4, $4, $5
 ; MIPS32-NEXT:    xori $4, $4, 1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -130,8 +122,7 @@ define i32 @ult(i32 %a, i32 %b) {
 ; MIPS32-LABEL: ult:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    sltu $4, $4, $5
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -146,8 +137,7 @@ define i32 @ule(i32 %a, i32 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    sltu $4, $5, $4
 ; MIPS32-NEXT:    xori $4, $4, 1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/mul.ll

@@ -28,8 +28,7 @@ define zeroext i8 @mul_i8_zext(i8 zeroext %a, i8 zeroext %b) {
 ; MIPS32-LABEL: mul_i8_zext:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    mul $4, $5, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 255
-; MIPS32-NEXT:    ori $5, $5, 255
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -66,8 +65,7 @@ define zeroext i16 @mul_i16_zext(i16 zeroext %a, i16 zeroext %b) {
 ; MIPS32-LABEL: mul_i16_zext:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    mul $4, $5, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 65535
-; MIPS32-NEXT:    ori $5, $5, 65535
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -122,13 +120,11 @@ define i128 @mul_i128(i128 %a, i128 %b) {
 ; MIPS32-NEXT:    mfhi $12
 ; MIPS32-NEXT:    addu $10, $10, $11
 ; MIPS32-NEXT:    sltu $11, $10, $11
-; MIPS32-NEXT:    lui $13, 0
+; MIPS32-NEXT:    ori $13, $zero, 1
-; MIPS32-NEXT:    ori $13, $13, 1
 ; MIPS32-NEXT:    and $11, $11, $13
 ; MIPS32-NEXT:    addu $10, $10, $12
 ; MIPS32-NEXT:    sltu $12, $10, $12
-; MIPS32-NEXT:    lui $13, 0
+; MIPS32-NEXT:    ori $13, $zero, 1
-; MIPS32-NEXT:    ori $13, $13, 1
 ; MIPS32-NEXT:    and $12, $12, $13
 ; MIPS32-NEXT:    addu $11, $11, $12
 ; MIPS32-NEXT:    mul $12, $3, $4
@@ -140,31 +136,26 @@ define i128 @mul_i128(i128 %a, i128 %b) {
 ; MIPS32-NEXT:    mfhi $24
 ; MIPS32-NEXT:    addu $12, $12, $13
 ; MIPS32-NEXT:    sltu $13, $12, $13
-; MIPS32-NEXT:    lui $25, 0
+; MIPS32-NEXT:    ori $25, $zero, 1
-; MIPS32-NEXT:    ori $25, $25, 1
 ; MIPS32-NEXT:    and $13, $13, $25
 ; MIPS32-NEXT:    addu $12, $12, $14
 ; MIPS32-NEXT:    sltu $14, $12, $14
-; MIPS32-NEXT:    lui $25, 0
+; MIPS32-NEXT:    ori $25, $zero, 1
-; MIPS32-NEXT:    ori $25, $25, 1
 ; MIPS32-NEXT:    and $14, $14, $25
 ; MIPS32-NEXT:    addu $13, $13, $14
 ; MIPS32-NEXT:    addu $12, $12, $15
 ; MIPS32-NEXT:    sltu $14, $12, $15
-; MIPS32-NEXT:    lui $15, 0
+; MIPS32-NEXT:    ori $15, $zero, 1
-; MIPS32-NEXT:    ori $15, $15, 1
 ; MIPS32-NEXT:    and $14, $14, $15
 ; MIPS32-NEXT:    addu $13, $13, $14
 ; MIPS32-NEXT:    addu $12, $12, $24
 ; MIPS32-NEXT:    sltu $14, $12, $24
-; MIPS32-NEXT:    lui $15, 0
+; MIPS32-NEXT:    ori $15, $zero, 1
-; MIPS32-NEXT:    ori $15, $15, 1
 ; MIPS32-NEXT:    and $14, $14, $15
 ; MIPS32-NEXT:    addu $13, $13, $14
 ; MIPS32-NEXT:    addu $12, $12, $11
 ; MIPS32-NEXT:    sltu $11, $12, $11
-; MIPS32-NEXT:    lui $14, 0
+; MIPS32-NEXT:    ori $14, $zero, 1
-; MIPS32-NEXT:    ori $14, $14, 1
 ; MIPS32-NEXT:    and $11, $11, $14
 ; MIPS32-NEXT:    addu $11, $13, $11
 ; MIPS32-NEXT:    mul $8, $8, $4
@@ -201,12 +192,10 @@ define void @umul_with_overflow(i32 %lhs, i32 %rhs, i32* %pmul, i1* %pcarry_flag
 ; MIPS32-NEXT:    mul $1, $4, $5
 ; MIPS32-NEXT:    multu $4, $5
 ; MIPS32-NEXT:    mfhi $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 0
-; MIPS32-NEXT:    ori $5, $5, 0
 ; MIPS32-NEXT:    xor $4, $4, $5
 ; MIPS32-NEXT:    sltu $4, $zero, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $4, $4, $5
 ; MIPS32-NEXT:    sb $4, 0($7)
 ; MIPS32-NEXT:    sw $1, 0($6)

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/phi.ll

@@ -6,8 +6,7 @@ define i1 @test_i1(i1 %cnd, i1 %a, i1 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    addiu $sp, $sp, -16
 ; MIPS32-NEXT:    .cfi_def_cfa_offset 16
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    sw $5, 12($sp) # 4-byte Folded Spill
 ; MIPS32-NEXT:    sw $6, 8($sp) # 4-byte Folded Spill
@@ -49,8 +48,7 @@ define i8 @test_i8(i1 %cnd, i8 %a, i8 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    addiu $sp, $sp, -16
 ; MIPS32-NEXT:    .cfi_def_cfa_offset 16
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    sw $5, 12($sp) # 4-byte Folded Spill
 ; MIPS32-NEXT:    sw $6, 8($sp) # 4-byte Folded Spill
@@ -92,8 +90,7 @@ define i16 @test_i16(i1 %cnd, i16 %a, i16 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    addiu $sp, $sp, -16
 ; MIPS32-NEXT:    .cfi_def_cfa_offset 16
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    sw $5, 12($sp) # 4-byte Folded Spill
 ; MIPS32-NEXT:    sw $6, 8($sp) # 4-byte Folded Spill
@@ -135,8 +132,7 @@ define i32 @test_i32(i1 %cnd, i32 %a, i32 %b) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    addiu $sp, $sp, -16
 ; MIPS32-NEXT:    .cfi_def_cfa_offset 16
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    sw $5, 12($sp) # 4-byte Folded Spill
 ; MIPS32-NEXT:    sw $6, 8($sp) # 4-byte Folded Spill

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/rem_and_div.ll

@@ -157,11 +157,9 @@ entry:
 define signext i8 @udiv_i8(i8 signext %a, i8 signext %b) {
 ; MIPS32-LABEL: udiv_i8:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 255
-; MIPS32-NEXT:    ori $1, $1, 255
 ; MIPS32-NEXT:    and $1, $5, $1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 255
-; MIPS32-NEXT:    ori $5, $5, 255
 ; MIPS32-NEXT:    and $4, $4, $5
 ; MIPS32-NEXT:    divu $zero, $1, $4
 ; MIPS32-NEXT:    teq $4, $zero, 7
@@ -178,11 +176,9 @@ entry:
 define signext i16 @udiv_i16(i16 signext %a, i16 signext %b) {
 ; MIPS32-LABEL: udiv_i16:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 65535
-; MIPS32-NEXT:    ori $1, $1, 65535
 ; MIPS32-NEXT:    and $1, $5, $1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 65535
-; MIPS32-NEXT:    ori $5, $5, 65535
 ; MIPS32-NEXT:    and $4, $4, $5
 ; MIPS32-NEXT:    divu $zero, $1, $4
 ; MIPS32-NEXT:    teq $4, $zero, 7
@@ -237,11 +233,9 @@ entry:
 define signext i8 @urem_i8(i8 signext %a, i8 signext %b) {
 ; MIPS32-LABEL: urem_i8:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 255
-; MIPS32-NEXT:    ori $1, $1, 255
 ; MIPS32-NEXT:    and $1, $5, $1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 255
-; MIPS32-NEXT:    ori $5, $5, 255
 ; MIPS32-NEXT:    and $4, $4, $5
 ; MIPS32-NEXT:    divu $zero, $1, $4
 ; MIPS32-NEXT:    teq $4, $zero, 7
@@ -258,11 +252,9 @@ entry:
 define signext i16 @urem_i16(i16 signext %a, i16 signext %b) {
 ; MIPS32-LABEL: urem_i16:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 65535
-; MIPS32-NEXT:    ori $1, $1, 65535
 ; MIPS32-NEXT:    and $1, $5, $1
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 65535
-; MIPS32-NEXT:    ori $5, $5, 65535
 ; MIPS32-NEXT:    and $4, $4, $5
 ; MIPS32-NEXT:    divu $zero, $1, $4
 ; MIPS32-NEXT:    teq $4, $zero, 7

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/select.ll

@@ -4,8 +4,7 @@
 define i8 @select_i8(i1 %test, i8 %a, i8 %b) {
 ; MIPS32-LABEL: select_i8:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    movn $6, $5, $1
 ; MIPS32-NEXT:    move $2, $6
@@ -19,8 +18,7 @@ entry:
 define i16 @select_i16(i1 %test, i16 %a, i16 %b) {
 ; MIPS32-LABEL: select_i16:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    movn $6, $5, $1
 ; MIPS32-NEXT:    move $2, $6
@@ -34,8 +32,7 @@ entry:
 define i32 @select_i32(i1 %test, i32 %a, i32 %b) {
 ; MIPS32-LABEL: select_i32:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    movn $6, $5, $1
 ; MIPS32-NEXT:    move $2, $6
@@ -49,8 +46,7 @@ entry:
 define i32* @select_ptr(i1 %test, i32* %a, i32* %b) {
 ; MIPS32-LABEL: select_ptr:
 ; MIPS32:       # %bb.0: # %entry
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $4, $1
 ; MIPS32-NEXT:    movn $6, $5, $1
 ; MIPS32-NEXT:    move $2, $6
@@ -66,8 +62,7 @@ define i32 @select_with_negation(i32 %a, i32 %b, i32 %x, i32 %y) {
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    slt $4, $4, $5
 ; MIPS32-NEXT:    not $4, $4
-; MIPS32-NEXT:    lui $5, 0
+; MIPS32-NEXT:    ori $5, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $4, $4, $5
 ; MIPS32-NEXT:    movn $7, $6, $4
 ; MIPS32-NEXT:    move $2, $7

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/stack_args.ll

@@ -13,8 +13,7 @@ define  i32 @g(i32  %x1, i32 %x2, i32 %x3, i32 %x4, i32 %x5){
 ; MIPS32-NEXT:    addiu $1, $sp, 48
 ; MIPS32-NEXT:    lw $1, 0($1)
 ; MIPS32-NEXT:    move $2, $sp
-; MIPS32-NEXT:    lui $3, 0
+; MIPS32-NEXT:    ori $3, $zero, 1
-; MIPS32-NEXT:    ori $3, $3, 16
 ; MIPS32-NEXT:    addu $2, $2, $3
 ; MIPS32-NEXT:    sw $1, 0($2)
 ; MIPS32-NEXT:    jal f

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/sub.ll

@@ -29,8 +29,7 @@ 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, $zero, 255
-; MIPS32-NEXT:    ori $5, $5, 255
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -67,8 +66,7 @@ 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, $zero, 65535
-; MIPS32-NEXT:    ori $5, $5, 65535
 ; MIPS32-NEXT:    and $2, $4, $5
 ; MIPS32-NEXT:    jr $ra
 ; MIPS32-NEXT:    nop
@@ -94,8 +92,7 @@ define i64 @sub_i64(i64 %a, i64 %b) {
 ; 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, $zero, 1
-; MIPS32-NEXT:    ori $6, $6, 1
 ; MIPS32-NEXT:    and $4, $4, $6
 ; MIPS32-NEXT:    subu $3, $5, $4
 ; MIPS32-NEXT:    jr $ra
@@ -119,32 +116,27 @@ define i128 @sub_i128(i128 %a, i128 %b) {
 ; 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, $zero, 1
-; 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, $zero, 1
-; 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, $zero, 1
-; 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, $zero, 1
-; 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, $zero, 1
-; MIPS32-NEXT:    ori $5, $5, 1
 ; MIPS32-NEXT:    and $3, $3, $5
 ; MIPS32-NEXT:    subu $5, $2, $3
 ; MIPS32-NEXT:    move $2, $9

llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/truncStore_and_aExtLoad.ll

@@ -27,8 +27,7 @@ define void @load_store_i1(i1* %px, i1* %py) {
 ; MIPS32-LABEL: load_store_i1:
 ; MIPS32:       # %bb.0: # %entry
 ; MIPS32-NEXT:    lbu $5, 0($5)
-; MIPS32-NEXT:    lui $1, 0
+; MIPS32-NEXT:    ori $1, $zero, 1
-; MIPS32-NEXT:    ori $1, $1, 1
 ; MIPS32-NEXT:    and $1, $5, $1
 ; MIPS32-NEXT:    sb $1, 0($4)
 ; MIPS32-NEXT:    jr $ra