Hi Moderators, I am trying variation of array reduction method sum in a constraint to understand it’s equivalent expression in each scenario. Here is my attempt Assume that out of C1 to C7 there is only one constraint active Have listed my queries in the edalink Thanks

A1) According to 7.12.4 Iterator index querying, the index type can be either an int or, for an associative array, it’s the same as the type of the array index. A2) Since addition has precedence over equality, the parentheses don’t affect the result. A3) Concatenation {} may have the lowest preced…

Thanks Dave. Two follow up questions (QA) Consider the following example from 1800-2023 section 18.5.7.2 class C; rand bit [7:0] A[]; constraint c1 {A.size == 5;} constraint c2 {A.sum() with (int'(item)) < 1000;} endclass The constraint c2 will be interpreted as ( int'(A[0])+int'(A[1])+int'(A[2…

Yes, the concatenation operator should be part of the equivalent expression for clarity. However, the LRM section 7.12.3 Array reduction methods does say: The method returns a single value of the same type as the array element type or, if specified, the type of the expression in the with clause. …

[image] dave_59: A1) According to 7.12.4 Iterator index querying, the index type can be either an int or, for an associative array, it’s the same as the type of the array index. I realized we had a similar discussion in an older thread

Hi Dave, An additional question on the related topic As per LRM the repeat operator in concatenation operation is required to be constant. Hence I can see the following repeat operator $size(arr) works as unpacked dimension is fixed class Fixed_Arr; rand bit[2:0] arr[4]; constrain…

You don’t need to concatenation here; use the shift operator instead. constraint SUM { arr.sum() with ( int'(item) ) == (1 << arr.size() ) - 1 ; }

Hi Dave, In the following code how would '1 be interpreted ? bit [63:0] arr[5]; initial begin repeat(5) begin if( !std::randomize(arr) with { arr.sum() with (70'(item)) == '1; } ) $display("Fails"); end end Would '1 be 32’hFFFF_FFFF or 70’h3F…

A self-determined context refers to an operand whose type remains unaffected by any external expression. For example, when we have $displayh( 0 + (‘1 << ‘1) );, it displays ffffffffe. This is because the result of the shift operation is incorporated into an addition expression that is being added to…

Thanks Dave [image] dave_59: $displayh( 0 + ('1 << '1) ); // O/P : fffffffe i.e 32’hffff_fffe As 0 is 32-bit, LHS of shift operator would be 32’hFFFF_FFFF On changing it to [image] dave_59: $displayh( 64’d0 + ('1 << '1) ); // O/P : fffffffffffffffe i.e 64’hffff_ffff_ffff_fffe Due …

It’s correct. The type of the resulting self-determined expression can be used to determine the type of another expression it’s a part of.

Understanding Array Reduction methods

SystemVerilog

LFT June 4, 2026, 6:32am 5

I realized we had a similar discussion in an older thread