[PATCH] D92438: [AArch64][GlobalISel] Don't explicitly write to the zero register in emitCMN

[Jessica Paquette via Phabricator via llvm-commits]

paquette created this revision.
paquette added a reviewer: aemerson.
Herald added subscribers: danielkiss, hiraditya, kristof.beyls, rovka.
Herald added a project: LLVM.
paquette requested review of this revision.

This case was missed in 78ccb0359d8da3269636d85933dd8afe50a2211f <https://reviews.llvm.org/rG78ccb0359d8da3269636d85933dd8afe50a2211f>.


https://reviews.llvm.org/D92438

Files:
  llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
  llvm/test/CodeGen/AArch64/GlobalISel/opt-fold-compare.mir


Index: llvm/test/CodeGen/AArch64/GlobalISel/opt-fold-compare.mir
===================================================================
--- llvm/test/CodeGen/AArch64/GlobalISel/opt-fold-compare.mir
+++ llvm/test/CodeGen/AArch64/GlobalISel/opt-fold-compare.mir
@@ -45,7 +45,7 @@
     ; CHECK: [[COPY:%[0-9]+]]:gpr32 = COPY $w0
     ; CHECK: [[COPY1:%[0-9]+]]:gpr32 = COPY $w1
     ; CHECK: [[COPY2:%[0-9]+]]:gpr32 = COPY $wzr
-    ; CHECK: $wzr = ADDSWrr [[COPY]], [[COPY1]], implicit-def $nzcv
+    ; CHECK: [[ADDSWrr:%[0-9]+]]:gpr32 = ADDSWrr [[COPY]], [[COPY1]], implicit-def $nzcv
     ; CHECK: [[CSINCWr:%[0-9]+]]:gpr32 = CSINCWr [[COPY2]], $wzr, 0, implicit $nzcv
     ; CHECK: $w0 = COPY [[CSINCWr]]
     ; CHECK: RET_ReallyLR implicit $w0
@@ -76,7 +76,7 @@
     ; CHECK: [[COPY:%[0-9]+]]:gpr32 = COPY $w0
     ; CHECK: [[COPY1:%[0-9]+]]:gpr32 = COPY $w1
     ; CHECK: [[COPY2:%[0-9]+]]:gpr32 = COPY $wzr
-    ; CHECK: $wzr = ADDSWrr [[COPY]], [[COPY1]], implicit-def $nzcv
+    ; CHECK: [[ADDSWrr:%[0-9]+]]:gpr32 = ADDSWrr [[COPY]], [[COPY1]], implicit-def $nzcv
     ; CHECK: [[CSINCWr:%[0-9]+]]:gpr32 = CSINCWr [[COPY2]], $wzr, 0, implicit $nzcv
     ; CHECK: $w0 = COPY [[CSINCWr]]
     ; CHECK: RET_ReallyLR implicit $w0
@@ -171,7 +171,7 @@
     ; CHECK: [[COPY:%[0-9]+]]:gpr64 = COPY $x0
     ; CHECK: [[COPY1:%[0-9]+]]:gpr64 = COPY $x1
     ; CHECK: [[COPY2:%[0-9]+]]:gpr64 = COPY $xzr
-    ; CHECK: $xzr = ADDSXrr [[COPY]], [[COPY1]], implicit-def $nzcv
+    ; CHECK: [[ADDSXrr:%[0-9]+]]:gpr64 = ADDSXrr [[COPY]], [[COPY1]], implicit-def $nzcv
     ; CHECK: [[CSINCXr:%[0-9]+]]:gpr64 = CSINCXr [[COPY2]], $xzr, 0, implicit $nzcv
     ; CHECK: $x0 = COPY [[CSINCXr]]
     ; CHECK: RET_ReallyLR implicit $x0
@@ -202,7 +202,7 @@
     ; CHECK: [[COPY:%[0-9]+]]:gpr64 = COPY $x0
     ; CHECK: [[COPY1:%[0-9]+]]:gpr64 = COPY $x1
     ; CHECK: [[COPY2:%[0-9]+]]:gpr64 = COPY $xzr
-    ; CHECK: $xzr = ADDSXrr [[COPY]], [[COPY1]], implicit-def $nzcv
+    ; CHECK: [[ADDSXrr:%[0-9]+]]:gpr64 = ADDSXrr [[COPY]], [[COPY1]], implicit-def $nzcv
     ; CHECK: [[CSINCXr:%[0-9]+]]:gpr64 = CSINCXr [[COPY2]], $xzr, 0, implicit $nzcv
     ; CHECK: $x0 = COPY [[CSINCXr]]
     ; CHECK: RET_ReallyLR implicit $x0
@@ -572,7 +572,7 @@
     ; CHECK-LABEL: name: cmn_s32_neg_imm
     ; CHECK: liveins: $w0, $w1
     ; CHECK: %reg0:gpr32sp = COPY $w0
-    ; CHECK: $wzr = SUBSWri %reg0, 1, 0, implicit-def $nzcv
+    ; CHECK: [[SUBSWri:%[0-9]+]]:gpr32 = SUBSWri %reg0, 1, 0, implicit-def $nzcv
     ; CHECK: %cmp:gpr32 = CSINCWr $wzr, $wzr, 0, implicit $nzcv
     ; CHECK: $w0 = COPY %cmp
     ; CHECK: RET_ReallyLR implicit $w0
@@ -600,7 +600,7 @@
     ; CHECK: liveins: $w0, $x0, $x1
     ; CHECK: %reg0:gpr64sp = COPY $x0
     ; CHECK: %reg1:gpr32 = COPY $w0
-    ; CHECK: $xzr = ADDSXrx %reg0, %reg1, 50, implicit-def $nzcv
+    ; CHECK: [[ADDSXrx:%[0-9]+]]:gpr64 = ADDSXrx %reg0, %reg1, 50, implicit-def $nzcv
     ; CHECK: %cmp:gpr32 = CSINCWr $wzr, $wzr, 0, implicit $nzcv
     ; CHECK: $w0 = COPY %cmp
     ; CHECK: RET_ReallyLR implicit $w0
Index: llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
===================================================================
--- llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
+++ llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
@@ -4040,7 +4040,8 @@
                                     MachineIRBuilder &MIRBuilder) const {
   MachineRegisterInfo &MRI = MIRBuilder.getMF().getRegInfo();
   bool Is32Bit = (MRI.getType(LHS.getReg()).getSizeInBits() == 32);
-  return emitADDS(Is32Bit ? AArch64::WZR : AArch64::XZR, LHS, RHS, MIRBuilder);
+  auto RC = Is32Bit ? &AArch64::GPR32RegClass : &AArch64::GPR64RegClass;
+  return emitADDS(MRI.createVirtualRegister(RC), LHS, RHS, MIRBuilder);
 }
 
 MachineInstr *


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