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Stop checking dtype for better optimization chance in BitOpTree (#2909) 

* Tests: Add more case that does not match native C++ width (8, 16, 32 or 64).

* Use AstVarRef::same() instead of AstNode::sameGateTree() because the latter checks dtype in addition to scope.

AstVarRef may have different minWidth in some cases,
but the difference should be ignored in the context of bitOpTree optimization.
This commit is contained in:
Yutetsu TAKATSUKASA 2021-05-04 10:40:16 +09:00 committed by GitHub
parent e68788d914
commit 8624ce6a84
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GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 10 additions and 8 deletions
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2
src/V3Const.cpp
View File

@ -100,7 +100,7 @@ class ConstBitOpTreeVisitor final : public AstNVisitor {
public:
// METHODS
bool hasConstantResult() const { return m_constResult >= 0; }
bool sameVarAs(const AstNodeVarRef* otherp) const { return m_refp->sameGateTree(otherp); }
bool sameVarAs(const AstNodeVarRef* otherp) const { return m_refp->same(otherp); }
void setPolarity(bool compBit, int bit) {
UASSERT_OBJ(!hasConstantResult(), m_refp, "Already has result of " << m_constResult);
UASSERT_OBJ(bit < VL_QUADSIZE, m_refp,

2
test_regress/t/t_const_opt_red.pl
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@ -19,7 +19,7 @@ execute(
);
if ($Self->{vlt}) {
file_grep($Self->{stats}, qr/Optimizations, Const bit op reduction\s+(\d+)/i, 135);
file_grep($Self->{stats}, qr/Optimizations, Const bit op reduction\s+(\d+)/i, 141);
}
ok(1);

10
test_regress/t/t_const_opt_red.v
View File

@ -162,7 +162,7 @@ module t(/*AUTOARG*/
$write("[%0t] cyc==%0d crc=%x sum=%x\n",$time, cyc, crc, sum);
if (crc !== 64'hc77bb9b3784ea091) $stop;
// What checksum will we end up with (above print should match)
`define EXPECTED_SUM 64'he9b854d521ebb8b6
`define EXPECTED_SUM 64'h727fb78d09c1981e
if (sum !== `EXPECTED_SUM) $stop;
$write("*-* All Finished *-*\n");
$finish;
@ -190,7 +190,9 @@ module Test(/*AUTOARG*/
output logic z1, z2, z3, z4, z5, z6, z7;
logic [127:0] d;
logic [17:0] e;
always_ff @(posedge clk) d <= {i, ~i, ~i, i};
always_ff @(posedge clk) e <= i[17:00];
always_ff @(posedge clk) begin
a1 <= (i[5] & ~i[3] & i[1]);
@ -203,7 +205,7 @@ module Test(/*AUTOARG*/
a8 <= &(~i[5:3]);
a9 <= ~i[5] & !i[4] & !i[3] && ~i[5] && !i[4];
a10 <= ~(i[5] & ~d[3]) & (!i[5] & d[1]); // cannot be optimized
a11 <= d[0] & d[33] & d[66] & d[99] & !d[31] & !d[62] & !d[93] & !d[124];
a11 <= d[0] & d[33] & d[66] & d[99] & !d[31] & !d[62] & !d[93] & !d[124] & e[0] & !e[1] & e[2];
//
o1 <= (~i[5] | i[3] | ~i[1]);
o2 <= (i[5]!=1 | i[3]!=0 | i[1]!=1);
@ -215,7 +217,7 @@ module Test(/*AUTOARG*/
o8 <= |(~i[5:3]);
o9 <= ~i[5] | !i[4] | ~i[3] || !i[5] || ~i[4];
o10 <= ~(~i[5] | d[3]) | (i[5] | ~d[1]); // cannot be optimized
o11 <= d[0] | d[33] | d[66] | d[99] | !d[31] | !d[62] | !d[93] | !d[124];
o11 <= d[0] | d[33] | d[66] | d[99] | !d[31] | !d[62] | !d[93] | !d[124] | e[0] | !e[1] | e[2];
//
x1 <= (i[5] ^ ~i[3] ^ i[1]);
x2 <= (i[5]==1 ^ i[3]==0 ^ i[1]==1);
@ -225,7 +227,7 @@ module Test(/*AUTOARG*/
x6 <= i[5] ^ ~i[3] ^ i[1] ^ i[3] ^ !i[1] ^ i[3] ^ ~i[1];
x7 <= i[5] ^ (^((i & 32'b001010) ^ 32'b001000));
x8 <= ~(~i[5] ^ d[3]) ^ (i[5] ^ ~d[1]);
x9 <= d[0] ^ d[33] ^ d[66] ^ d[99] ^ !d[31] ^ !d[62] ^ !d[93] ^ !d[124];
x9 <= d[0] ^ d[33] ^ d[66] ^ d[99] ^ !d[31] ^ !d[62] ^ !d[93] ^ !d[124] ^ e[0] ^ !e[1] ^ e[2];
//
// All zero/all one cases
z1 <= (i[5] & ~i[3] & ~i[5]);

2
test_regress/t/t_func_crc.pl
View File

@ -19,7 +19,7 @@ execute(
);
if ($Self->{vlt}) {
file_grep($Self->{stats}, qr/Optimizations, Const bit op reduction\s+(\d+)/i, 3870);
file_grep($Self->{stats}, qr/Optimizations, Const bit op reduction\s+(\d+)/i, 3888);
}
ok(1);

2
test_regress/t/t_gate_ormux.pl
View File

@ -19,7 +19,7 @@ compile(
);
if ($Self->{vlt}) {
file_grep($Self->{stats}, qr/Optimizations, Const bit op reduction\s+(\d+)/i, 898);
file_grep($Self->{stats}, qr/Optimizations, Const bit op reduction\s+(\d+)/i, 994);
}
execute(