[CIR] [Lowering] Fix handling of multiple array for ZeroAttr (#970)

This is the following up fix for the previous fix
#961

See the attached new test for the reproducer.

Sorry for the initial overlook.

Author: ChuanqiXu9

clang/lib/CIR/Lowering/LoweringHelpers.cpp

@@ -85,8 +85,10 @@ void convertToDenseElementsAttrImpl(
       continue;
     }
 
-    if (mlir::isa<mlir::cir::ZeroAttr>(eltAttr))
+    if (mlir::isa<mlir::cir::ZeroAttr>(eltAttr)) {
+      currentIndex += elementsSizeInCurrentDim;
       continue;
+    }
 
     llvm_unreachable("unknown element in ConstArrayAttr");
   }

clang/test/CIR/Lowering/multi-array.c

@@ -34,3 +34,25 @@ unsigned char table3[15][16] =
 };
 
 // LLVM: @table3 = {{.*}}[15 x [16 x i8]] {{.*}}[16 x i8] c"\01\01\00\00\00\00\00\00\00\00\00\00\00\00\00\00", [16 x i8] c"\01\02\02\00\00\00\00\00\00\00\00\00\00\00\00\00", [16 x i8] c"\02\02\02\02\00\00\00\00\00\00\00\00\00\00\00\00", [16 x i8] c"\02\02\02\03\03\00\00\00\00\00\00\00\00\00\00\00", [16 x i8] c"\02\02\03\03\03\03\00\00\00\00\00\00\00\00\00\00", [16 x i8] c"\02\03\03\03\03\03\03\00\00\00\00\00\00\00\00\00", [16 x i8] c"\03\03\03\03\03\03\03\04\05\06\07\08\09\0A\0B\00", [16 x i8] zeroinitializer
+
+
+unsigned char table4[][20] =
+{
+  {  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+  {  0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 2, 2, 2, 2, 0, 0, 0, 0 }
+};
+// LLVM: @table4 = {{.*}}[2 x [20 x i8]] {{.*}}[20 x i8] zeroinitializer, [20 x i8] c"\00\00\00\00\00\00\00\01\01\01\01\00\02\02\02\02\00\00\00\00"]
+
+unsigned char table5[][20] =
+{
+  {  0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+  {  0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 2, 2, 2, 2, 0, 0, 0, 0 }
+};
+// LLVM: @table5 = {{.*}}[2 x [20 x i8]] {{.*}}[20 x i8] c"\00\00\00\00\00\00\00\01\00\00\00\00\00\00\00\00\00\00\00\00", [20 x i8] c"\00\00\00\00\00\00\00\01\01\01\01\00\02\02\02\02\00\00\00\00"]
+
+unsigned char table6[][20] =
+{
+  {  1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+  {  0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 2, 2, 2, 2, 0, 0, 0, 0 }
+};
+// LLVM: @table6 = {{.*}}[2 x [20 x i8]] {{.*}}[20 x i8] c"\01\00\00\00\00\00\00\01\00\00\00\00\00\00\00\00\00\00\00\00", [20 x i8] c"\00\00\00\00\00\00\00\01\01\01\01\00\02\02\02\02\00\00\00\00"]