From 4925f9ad73ea229f9a804021105a2fc666f319d7 Mon Sep 17 00:00:00 2001
From: Paul Swirhun <63216497+paul-demo@users.noreply.github.com>
Date: Tue, 10 Jun 2025 14:39:13 -0700
Subject: [PATCH] Support 1-bit params with -G and -pvalue (#6051) (#6082)

---
 src/V3AstNodes.cpp                 | 2 +-
 test_regress/t/t_flag_parameter.v  | 9 +++++++++
 test_regress/t/t_flag_parameter.vc | 8 ++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/V3AstNodes.cpp b/src/V3AstNodes.cpp
index 9b5c9947f..8981bfc0c 100644
--- a/src/V3AstNodes.cpp
+++ b/src/V3AstNodes.cpp
@@ -425,7 +425,7 @@ AstConst* AstConst::parseParamLiteral(FileLine* fl, const string& literal) {
         // the Verilog literal parser.
         char* endp;
         const int v = strtol(literal.c_str(), &endp, 0);
-        if ((v != 0) && (endp[0] == 0)) {  // C literal
+        if ((v != 0) && (v != 1) && (endp[0] == 0)) {  // C literal
             return new AstConst{fl, AstConst::Signed32{}, v};
         } else {  // Try a Verilog literal (fatals if not)
             return new AstConst{fl, AstConst::StringToParse{}, literal.c_str()};
diff --git a/test_regress/t/t_flag_parameter.v b/test_regress/t/t_flag_parameter.v
index f4f330d26..68759b7d4 100644
--- a/test_regress/t/t_flag_parameter.v
+++ b/test_regress/t/t_flag_parameter.v
@@ -57,6 +57,11 @@ module t;
    parameter int71 = 1;
    parameter int72 = 1;
 
+   parameter bit bit0to0 = 0;
+   parameter bit bit1to1 = 1;
+   parameter bit bit0to1 = 0;
+   parameter bit bit1to0 = 1;
+
    initial begin
       `check(string1,"New String");
       `check(string2,"New String");
@@ -88,6 +93,10 @@ module t;
       `check(int62,32'hdeadbeef);
       `check(int71,-1000);
       `check(int72,-1000);
+      `check(bit0to0, 1'b0);
+      `check(bit1to1, 1'b1);
+      `check(bit0to1, 1'b1);
+      `check(bit1to0, 1'b0);
 
       // Check parameter assigned simple integer literal is signed
       if ((int11 << 27) >>> 31 != -1) $stop;
diff --git a/test_regress/t/t_flag_parameter.vc b/test_regress/t/t_flag_parameter.vc
index 35687e39e..6bac0b290 100644
--- a/test_regress/t/t_flag_parameter.vc
+++ b/test_regress/t/t_flag_parameter.vc
@@ -28,3 +28,11 @@
 -pvalue+int62="32'hdead_beef"
 -Gint71=-1000
 -pvalue+int72=-1000
+-Gbit0to0=0
+-pvalue+bit0to0=0
+-Gbit1to1=1
+-pvalue+bit1to1=1
+-Gbit0to1=1
+-pvalue+bit0to1=1
+-Gbit1to0=0
+-pvalue+bit1to0=0