[AMDGPU][GlobalISel] Fix mapping G_FREEZE

[arsenm]

The verifier probably shouldn't allow freeze to change the regbank

llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp

const RegisterBank *DstBank = getRegBank(MI.getOperand(0).getReg(), MRI,
                                              *TRI);
     const RegisterBank *SrcBank = getRegBank(MI.getOperand(1).getReg(), MRI,
                                              *TRI);
     assert(SrcBank && "src bank should have been assigned already");
     if (!DstBank)
       DstBank = SrcBank;
 
     unsigned Size = getSizeInBits(MI.getOperand(0).getReg(), MRI, *TRI);
-    if (cannotCopy(*DstBank, *SrcBank, Size))
+    if (MI.getOpcode() != AMDGPU::G_FREEZE &&
+        cannotCopy(*DstBank, *SrcBank, Size))
       return getInvalidInstructionMapping();
 
     const ValueMapping &ValMap = getValueMapping(0, Size, *DstBank);
     unsigned OpdsMappingSize = MI.isCopy() ? 1 : 2;
     SmallVector<const ValueMapping *, 1> OpdsMapping(OpdsMappingSize);
     OpdsMapping[0] = &ValMap;
     if (MI.getOpcode() == AMDGPU::G_FREEZE)
       OpdsMapping[1] = &ValMap;

llvm/test/CodeGen/AMDGPU/GlobalISel/regbankselect-freeze.mir

bb.0:
     %1:_(s1) = G_TRUNC %0(s32)
     %2:_(s1) = G_FREEZE %1
     %3:_(s32) = G_ANYEXT %2(s1)
     $agpr0 = COPY %3(s32)
 
 ...
 
 ---
+name: test_freeze_s1_sgpr_to_sgpr
+legalized: true
+body:             |
+  bb.0:
+    liveins: $sgpr0
+
+    ; CHECK-LABEL: name: test_freeze_s1_sgpr_to_sgpr
+    ; CHECK: liveins: $sgpr0
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK-NEXT: [[TRUNC:%[0-9]+]]:sgpr(s1) = G_TRUNC [[COPY]](s32)
+    ; CHECK-NEXT: [[FREEZE:%[0-9]+]]:sgpr(s1) = G_FREEZE [[TRUNC]]
+    ; CHECK-NEXT: [[ANYEXT:%[0-9]+]]:sgpr(s32) = G_ANYEXT [[FREEZE]](s1)
+    ; CHECK-NEXT: $sgpr0 = COPY [[ANYEXT]](s32)
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s1) = G_TRUNC %0(s32)
+    %2:_(s1) = G_FREEZE %1
+    %3:_(s32) = G_ANYEXT %2(s1)
+    $sgpr0 = COPY %3(s32)
+
+...
+
+---
 name: test_freeze_s1_vcc
 legalized: true
 
 body: |
   bb.0:
     liveins: $vgpr0, $vgpr1
     ; CHECK-LABEL: name: test_freeze_s1_vcc
     ; CHECK: liveins: $vgpr0, $vgpr1