GlobalISel: Verify G_BITCAST

[arsenm]

r351594

lib/CodeGen/MachineVerifier.cpp

if (!DstTy.isValid() ||
                          return false;
                        return true;
                      }))
       report("Generic Instruction G_PHI has operands with incompatible/missing "
              "types",
              MI);
     break;
   }
+  case TargetOpcode::G_BITCAST: {
+    LLT DstTy = MRI->getType(MI->getOperand(0).getReg());
+    LLT SrcTy = MRI->getType(MI->getOperand(1).getReg());
+    if (!DstTy.isValid() || !SrcTy.isValid())
+      break;
+
+    if (SrcTy.isPointer() != DstTy.isPointer())
+      report("bitcast cannot convert between pointers and other types", MI);
+
+    if (SrcTy.getSizeInBits() != DstTy.getSizeInBits())
+      report("bitcast sizes must match", MI);
+    break;
+  }
   case TargetOpcode::G_SEXT:
   case TargetOpcode::G_ZEXT:
   case TargetOpcode::G_ANYEXT:
   case TargetOpcode::G_TRUNC:
   case TargetOpcode::G_FPEXT:
   case TargetOpcode::G_FPTRUNC: {
     // Number of operands and presense of types is already checked (and
     // reported in case of any issues), so no need to report them again. As

test/Verifier/test_g_bitcast.mir

+#RUN: not llc -mtriple=amdgcn-amd-amdhsa -o - -global-isel -run-pass=none -verify-machineinstrs %s 2>&1 | FileCheck %s
+# REQUIRES: global-isel, amdgpu-registered-target
+
+---
+name:            test_bitcast
+legalized:       true
+regBankSelected: false
+selected:        false
+tracksRegLiveness: true
+liveins:
+body:             |
+  bb.0:
+   ; CHECK:  Bad machine code: bitcast cannot convert between pointers and other types
+    %0:_(s64) = G_IMPLICIT_DEF
+    %1:_(p0) = G_BITCAST %0
+
+    ; CHECK:  Bad machine code: bitcast cannot convert between pointers and other
+    %2:_(p0) = G_IMPLICIT_DEF
+    %3:_(s64) = G_BITCAST %2
+
+    ; CHECK: Bad machine code: bitcast sizes must match
+    %4:_(s32) = G_IMPLICIT_DEF
+    %5:_(s64) = G_BITCAST %4
+
+    ; CHECK: Bad machine code: bitcast sizes must match
+    %6:_(s32) = G_IMPLICIT_DEF
+    %7:_(<3 x s8>) = G_BITCAST %6
+
+    ; CHECK: Bad machine code: bitcast sizes must match
+    %8:_(p1) = G_IMPLICIT_DEF
+    %9:_(p3) = G_BITCAST %8
+
+    ; CHECK: Bad machine code: bitcast sizes must match
+    %10:_(p1) = G_IMPLICIT_DEF
+    %11:_(p3) = G_BITCAST %8
+
+...