[GlobalISel] support lowering of G_SHUFFLEVECTOR with pointer args (#141959)

Author: stanleygambarin

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

@@ -8446,10 +8446,10 @@ LegalizerHelper::lowerShuffleVector(MachineInstr &MI) {
     }
   }
 
-  if (DstTy.isScalar())
-    MIRBuilder.buildCopy(DstReg, BuildVec[0]);
-  else
+  if (DstTy.isVector())
     MIRBuilder.buildBuildVector(DstReg, BuildVec);
+  else
+    MIRBuilder.buildCopy(DstReg, BuildVec[0]);
   MI.eraseFromParent();
   return Legalized;
 }

llvm/test/CodeGen/AMDGPU/GlobalISel/shufflevector-pointer-crash.mir

@@ -0,0 +1,36 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -march=amdgcn -run-pass=legalizer %s -o - | FileCheck %s
+
+---
+name:            test
+tracksRegLiveness: true
+body: |
+  bb.0:
+    ; CHECK-LABEL: name: test
+    ; CHECK: [[C:%[0-9]+]]:_(p0) = G_CONSTANT i64 0
+    ; CHECK-NEXT: [[LOAD:%[0-9]+]]:_(s32) = G_LOAD [[C]](p0) :: (load (s32), align 16)
+    ; CHECK-NEXT: [[C1:%[0-9]+]]:_(p0) = G_CONSTANT i64 4
+    ; CHECK-NEXT: [[LOAD1:%[0-9]+]]:_(s32) = G_LOAD [[C1]](p0) :: (load (s32) from unknown-address + 4)
+    ; CHECK-NEXT: [[C2:%[0-9]+]]:_(p0) = G_CONSTANT i64 8
+    ; CHECK-NEXT: [[LOAD2:%[0-9]+]]:_(s32) = G_LOAD [[C2]](p0) :: (load (s32) from unknown-address + 8, align 8)
+    ; CHECK-NEXT: [[C3:%[0-9]+]]:_(p0) = G_CONSTANT i64 12
+    ; CHECK-NEXT: [[LOAD3:%[0-9]+]]:_(s32) = G_LOAD [[C3]](p0) :: (load (s32) from unknown-address + 12)
+    ; CHECK-NEXT: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s32>) = G_BUILD_VECTOR [[LOAD]](s32), [[LOAD1]](s32), [[LOAD2]](s32), [[LOAD3]](s32)
+    ; CHECK-NEXT: [[BITCAST:%[0-9]+]]:_(<2 x p0>) = G_BITCAST [[BUILD_VECTOR]](<4 x s32>)
+    ; CHECK-NEXT: [[UV:%[0-9]+]]:_(p0), [[UV1:%[0-9]+]]:_(p0) = G_UNMERGE_VALUES [[BITCAST]](<2 x p0>)
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(p0) = COPY [[UV]](p0)
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(p0) = COPY [[COPY]](p0)
+    ; CHECK-NEXT: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[COPY1]](p0)
+    ; CHECK-NEXT: $vgpr0 = COPY [[UV2]](s32)
+    ; CHECK-NEXT: $vgpr1 = COPY [[UV3]](s32)
+    ; CHECK-NEXT: SI_RETURN implicit $vgpr0, implicit $vgpr1
+    %0:_(p0) = G_CONSTANT i64 0
+    %1:_(<2 x p0>) = G_BUILD_VECTOR %0:_(p0), %0:_(p0)
+    %2:_(<2 x p0>) = G_LOAD %0:_(p0) :: (load (<2 x p0>))
+    %3:_(p0) = G_SHUFFLE_VECTOR %2:_(<2 x p0>), %1:_, shufflemask(0)
+    %4:_(s32), %5:_(s32) = G_UNMERGE_VALUES %3:_(p0)
+    $vgpr0 = COPY %4:_(s32)
+    $vgpr1 = COPY %5:_(s32)
+    SI_RETURN implicit $vgpr0, implicit $vgpr1
+...
+