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Merge pull request #5148 from georgerennie/george/convertible_to_int_fix

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Fix convertible_to_int handling of 32 bit unsigned ints with MSB set.
This commit is contained in:
George Rennie 2025-05-29 10:33:12 +01:00 • committed by GitHub
commit 3ef4c91c31
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2 changed files with 65 additions and 13 deletions
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31
kernel/rtlil.cc
View file

@ -383,7 +383,23 @@ int RTLIL::Const::as_int(bool is_signed) const
bool RTLIL::Const::convertible_to_int(bool is_signed) const
{
auto size = get_min_size(is_signed);
return (size > 0 && size <= 32);
if (size <= 0)
return false;
// If it fits in 31 bits it is definitely convertible
if (size <= 31)
return true;
// If it fits in 32 bits, it is convertible if signed or if unsigned and the
// leading bit is not 1
if (size == 32) {
if (is_signed)
return true;
return get_bits().at(31) != State::S1;
}
return false;
}
std::optional<int> RTLIL::Const::try_as_int(bool is_signed) const
@ -439,18 +455,7 @@ void RTLIL::Const::compress(bool is_signed)
std::optional<int> RTLIL::Const::as_int_compress(bool is_signed) const
{
auto size = get_min_size(is_signed);
if(size == 0 || size > 32)
return std::nullopt;
int32_t ret = 0;
for (auto i = 0; i < size && i < 32; i++)
if ((*this)[i] == State::S1)
ret |= 1 << i;
if (is_signed && (*this)[size-1] == State::S1)
for (auto i = size; i < 32; i++)
ret |= 1 << i;
return ret;
return try_as_int(is_signed);
}
std::string RTLIL::Const::as_string(const char* any) const

47
tests/opt/opt_expr_shift.ys
View file

@ -111,3 +111,50 @@ select -assert-none t:$shr
select -assert-none t:$sshl
select -assert-none t:$sshr
select -assert-none t:$shiftx
design -reset
read_verilog <<EOT
module top (
input wire [3:0] in,
output wire [7:0] shl,
output wire [7:0] shr,
output wire [7:0] sshl,
output wire [7:0] sshr,
output wire [7:0] shiftx,
output wire [7:0] shl_s,
output wire [7:0] shr_s,
output wire [7:0] sshl_s,
output wire [7:0] sshr_s,
output wire [7:0] shiftx_s,
);
assign shl = in << 32'hffffffff;
assign shr = in >> 32'hffffffff;
assign sshl = in <<< 32'hffffffff;
assign sshr = in >>> 32'hffffffff;
assign shiftx = in[32'hffffffff +: 8];
wire signed [31:0] shamt = 32'hffffffff;
assign shl_s = in << shamt;
assign shr_s = in >> shamt;
assign sshl_s = in <<< shamt;
assign sshr_s = in >>> shamt;
assign shiftx_s = in[shamt +: 8];
endmodule
EOT
select -assert-count 2 t:$shl
select -assert-count 2 t:$shr
select -assert-count 2 t:$sshl
select -assert-count 2 t:$sshr
select -assert-count 1 t:$shiftx
equiv_opt opt_expr
design -load postopt
select -assert-none t:$shl
select -assert-none t:$shr
select -assert-none t:$sshl
select -assert-none t:$sshr
select -assert-none t:$shiftx