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Bug #9594

closed

extra 'BVEXTRACT' operation in right hand side expression in 'assign' block's statement

Added by Sergey Smolov over 5 years ago. Updated about 5 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Alexander Kamkin
Target version:
0.1
Start date:
04/10/2019
Due date:
% Done:

100%

Estimated time:
Detected in build:
master
Platform:
Published in build:
0.1.2-beta-190909

Description

In texas97-tests/ifetch/IFetch.v module the 'MUX5_30' sub-module is instantiated:

MUX5_30    MUX5_30_EarlyPC (
    NewEarlyPC_s1r,
    PCPlus_s1r, {PCChain_s1e[29:26], PCImmedBus_s1e},
    ASBus_s1e[31:2], ExceptionPC_s1[29:0], IStallPC_s1,
    Jump0_s1e, Jump1_s1e, Jump2_s1e, Jump3_s1e, Jump4_s1e);
...
module MUX5_30 (out, in1, in2, in3, in4, in5, sel1, sel2, sel3, sel4, sel5);
    output      [29:0]  out;
    input       [29:0]  in1;
    input       [29:0]  in2;
    input       [29:0]  in3;
    input       [29:0]  in4;
    input       [29:0]  in5;
    input               sel1;
    input               sel2;
    input               sel3;
    input               sel4;
    input               sel5;
    wire        [29:0]  out_b;
    assign
        out_b = (sel5 == 1'b1) ? ~in5 : 30'b0,
        out_b = (sel4 == 1'b1) ? ~in4 : 30'b0,
        out_b = (sel3 == 1'b1) ? ~in3 : 30'b0,
        out_b = (sel2 == 1'b1) ? ~in2 : 30'b0,
        out_b = (sel1 == 1'b1) ? ~in1 : 30'b0;
    assign out = ~out_b;
endmodule

The sub-module's instance takes 'ASBus_s1e[31:2]' as 'in3' 30-bit size input. The AST for this assignment looks as follows (run ru.ispras.verilog.parser.sample.IfetchTestCase to reproduce)

module MUX5_30(out /* DECL: out */, in1 /* DECL: in1 */, in2 /* DECL: in2 */, in3 /* DECL: in3 */, in4 /* DECL: in4 */, in5 /* DECL: in5 */, sel1 /* DECL: sel1 */, sel2 /* DECL: sel2 */, sel3 /* DECL: sel3 */, sel4 /* DECL: sel4 */, sel5 /* DECL: sel5 */, out /* DECL: out */, in1 /* DECL: in1 */, in2 /* DECL: in2 */, in3 /* DECL: in3 */, in4 /* DECL: in4 */, in5 /* DECL: in5 */, sel1 /* DECL: sel1 */, sel2 /* DECL: sel2 */, sel3 /* DECL: sel3 */, sel4 /* DECL: sel4 */, sel5 /* DECL: sel5 */);
  output [00000000000000000000000000011101 /* 00000000000000000000000000011101 */:00000000000000000000000000000000 /* 00000000000000000000000000000000 */] out;
  input [00000000000000000000000000011101 /* 00000000000000000000000000011101 */:00000000000000000000000000000000 /* 00000000000000000000000000000000 */] in1;
  input [00000000000000000000000000011101 /* 00000000000000000000000000011101 */:00000000000000000000000000000000 /* 00000000000000000000000000000000 */] in2;
  input [00000000000000000000000000011101 /* 00000000000000000000000000011101 */:00000000000000000000000000000000 /* 00000000000000000000000000000000 */] in3;
  input [00000000000000000000000000011101 /* 00000000000000000000000000011101 */:00000000000000000000000000000000 /* 00000000000000000000000000000000 */] in4;
  input [00000000000000000000000000011101 /* 00000000000000000000000000011101 */:00000000000000000000000000000000 /* 00000000000000000000000000000000 */] in5;
  input sel1;
  input sel2;
  input sel3;
  input sel4;
  input sel5;
  wire [00000000000000000000000000011101 /* 00000000000000000000000000011101 */:00000000000000000000000000000000 /* 00000000000000000000000000000000 */] out_b;
  assign out_b /* DECL: out_b */ = ((sel5 == 1) ?  ~ in5 : 000000000000000000000000000000) /* (ITE (EQ sel5 1) (BVNOT in5) 000000000000000000000000000000) */;
  assign out_b /* DECL: out_b */ = ((sel4 == 1) ?  ~ in4 : 000000000000000000000000000000) /* (ITE (EQ sel4 1) (BVNOT in4) 000000000000000000000000000000) */;
  assign out_b /* DECL: out_b */ = ((sel3 == 1) ?  ~ in3 : 000000000000000000000000000000) /* (ITE (EQ sel3 1) (BVNOT in3) 000000000000000000000000000000) */;
  assign out_b /* DECL: out_b */ = ((sel2 == 1) ?  ~ in2 : 000000000000000000000000000000) /* (ITE (EQ sel2 1) (BVNOT in2) 000000000000000000000000000000) */;
  assign out_b /* DECL: out_b */ = ((sel1 == 1) ?  ~ in1 : 000000000000000000000000000000) /* (ITE (EQ sel1 1) (BVNOT in1) 000000000000000000000000000000) */;
  assign out /* DECL: out */ =  ~ out_b /* (BVNOT out_b) */;
endmodule

...

assign PCUnitDatapath.MUX5_30_EarlyPC.out_b = ((Jump2_s1e == 1) ?  ~ ASBus_s1e[31:2][31:2] : 000000000000000000000000000000);

When 'getRhsExpression()' method is called for the appropriate VerilogAssignment object, it returns:

(ITE (EQ Jump2_s1e 1) (BVNOT (BVEXTRACT 31 2 (BVEXTRACT 31 2 ASBus_s1e))) 000000000000000000000000000000)

An extra "BVEXTRACT" seems to be erroneous here.

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