diff --git a/cad/py-pymtl/Makefile b/cad/py-pymtl/Makefile
index 64ecf42ff390..1f02321dfade 100644
--- a/cad/py-pymtl/Makefile
+++ b/cad/py-pymtl/Makefile
@@ -1,27 +1,32 @@
 PORTNAME=	pymtl
-DISTVERSION=	3.1.14
-PORTREVISION=	1
+DISTVERSION=	3.1.15
 CATEGORIES=	cad python
 MASTER_SITES=	PYPI
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
 PKGNAMESUFFIX=	${PORTVERSION:R:R}
 DISTNAME=	${PORTNAME}${PORTVERSION:R:R}-${DISTVERSION}
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Python-based hardware generation, simulation, verification framework
 WWW=		https://github.com/pymtl/pymtl3
 
 LICENSE=	BSD3CLAUSE
 
 RUN_DEPENDS=	\
 		${PYTHON_PKGNAMEPREFIX}cffi>0:devel/py-cffi@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}greenlet>0:devel/py-greenlet@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}hypothesis>=4.18.1:devel/py-hypothesis@${PY_FLAVOR} \
+		${PYTHON_PKGNAMEPREFIX}py>0:devel/py-py@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}pytest>0:devel/py-pytest@${PY_FLAVOR}
+TEST_DEPENDS=	${PYTHON_PKGNAMEPREFIX}graphviz>0:graphics/py-graphviz@${PY_FLAVOR} \
+		verilator:cad/verilator \
+		yosys:cad/yosys
 
 USES=		python:3.6+
-USE_PYTHON=	autoplist distutils
+USE_PYTHON=	autoplist distutils pytest # 94 tests fail, see https://github.com/pymtl/pymtl3/issues/247
+
+BINARY_ALIAS=	g++=${CXX}
 
 NO_ARCH=	yes
 
 .include <bsd.port.mk>
diff --git a/cad/py-pymtl/distinfo b/cad/py-pymtl/distinfo
index 21b32519c01b..7ae827557409 100644
--- a/cad/py-pymtl/distinfo
+++ b/cad/py-pymtl/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1652630096
-SHA256 (pymtl3-3.1.14.tar.gz) = b2bdbba271a99c6cbdd0061db304a2239a26bbf28739a9005a0c22ab92538b5d
-SIZE (pymtl3-3.1.14.tar.gz) = 349905
+TIMESTAMP = 1686520242
+SHA256 (pymtl3-3.1.15.tar.gz) = dfb1e7f625bfe280eb7bc7ca9bfa95a5f8b01b07eb4e8cd5d8f6af83d1faa885
+SIZE (pymtl3-3.1.15.tar.gz) = 349707
diff --git a/cad/py-pymtl/files/patch-pymtl3_passes_backends_verilog_import___VerilogVerilatorImportConfigs.py b/cad/py-pymtl/files/patch-pymtl3_passes_backends_verilog_import___VerilogVerilatorImportConfigs.py
new file mode 100644
index 000000000000..d8aee4a4357f
--- /dev/null
+++ b/cad/py-pymtl/files/patch-pymtl3_passes_backends_verilog_import___VerilogVerilatorImportConfigs.py
@@ -0,0 +1,18 @@
+- remove GCC compiler flags, because we use clang
+
+--- pymtl3/passes/backends/verilog/import_/VerilogVerilatorImportConfigs.py.orig	2023-06-11 22:18:55 UTC
++++ pymtl3/passes/backends/verilog/import_/VerilogVerilatorImportConfigs.py
+@@ -317,9 +317,11 @@ class VerilogVerilatorImportConfigs( BasePassConfigs )
+     # (7/9/2020): Use -O0 by default so that normally the tests are super fast and don't corrupt cffi,
+     # but when the user gives a "fast" flag, it uses -O1.
+     if s.fast:
+-      c_flags = "-O1 -fno-guess-branch-probability -fno-reorder-blocks -fno-if-conversion -fno-if-conversion2 -fno-dce -fno-delayed-branch -fno-dse -fno-auto-inc-dec -fno-branch-count-reg -fno-combine-stack-adjustments -fno-cprop-registers -fno-forward-propagate -fno-inline-functions-called-once -fno-ipa-profile -fno-ipa-pure-const -fno-ipa-reference -fno-move-loop-invariants -fno-omit-frame-pointer -fno-split-wide-types -fno-tree-bit-ccp -fno-tree-ccp -fno-tree-ch -fno-tree-coalesce-vars -fno-tree-copy-prop -fno-tree-dce -fno-tree-dominator-opts -fno-tree-dse -fno-tree-fre -fno-tree-phiprop -fno-tree-pta -fno-tree-scev-cprop -fno-tree-sink -fno-tree-slsr -fno-tree-sra -fno-tree-ter -fno-tree-reassoc -fPIC -fno-gnu-unique -shared"
++      #c_flags = "-O1 -fno-guess-branch-probability -fno-reorder-blocks -fno-if-conversion -fno-if-conversion2 -fno-dce -fno-delayed-branch -fno-dse -fno-auto-inc-dec -fno-branch-count-reg -fno-combine-stack-adjustments -fno-cprop-registers -fno-forward-propagate -fno-inline-functions-called-once -fno-ipa-profile -fno-ipa-pure-const -fno-ipa-reference -fno-move-loop-invariants -fno-omit-frame-pointer -fno-split-wide-types -fno-tree-bit-ccp -fno-tree-ccp -fno-tree-ch -fno-tree-coalesce-vars -fno-tree-copy-prop -fno-tree-dce -fno-tree-dominator-opts -fno-tree-dse -fno-tree-fre -fno-tree-phiprop -fno-tree-pta -fno-tree-scev-cprop -fno-tree-sink -fno-tree-slsr -fno-tree-sra -fno-tree-ter -fno-tree-reassoc -fPIC -fno-gnu-unique -shared"
++      c_flags = "-O1 -fPIC -shared"
+     else:
+-      c_flags = "-O0 -fno-guess-branch-probability -fno-reorder-blocks -fno-if-conversion -fno-if-conversion2 -fno-dce -fno-delayed-branch -fno-dse -fno-auto-inc-dec -fno-branch-count-reg -fno-combine-stack-adjustments -fno-cprop-registers -fno-forward-propagate -fno-inline-functions-called-once -fno-ipa-profile -fno-ipa-pure-const -fno-ipa-reference -fno-move-loop-invariants -fno-omit-frame-pointer -fno-split-wide-types -fno-tree-bit-ccp -fno-tree-ccp -fno-tree-ch -fno-tree-coalesce-vars -fno-tree-copy-prop -fno-tree-dce -fno-tree-dominator-opts -fno-tree-dse -fno-tree-fre -fno-tree-phiprop -fno-tree-pta -fno-tree-scev-cprop -fno-tree-sink -fno-tree-slsr -fno-tree-sra -fno-tree-ter -fno-tree-reassoc -fPIC -fno-gnu-unique -shared"
++      #c_flags = "-O0 -fno-guess-branch-probability -fno-reorder-blocks -fno-if-conversion -fno-if-conversion2 -fno-dce -fno-delayed-branch -fno-dse -fno-auto-inc-dec -fno-branch-count-reg -fno-combine-stack-adjustments -fno-cprop-registers -fno-forward-propagate -fno-inline-functions-called-once -fno-ipa-profile -fno-ipa-pure-const -fno-ipa-reference -fno-move-loop-invariants -fno-omit-frame-pointer -fno-split-wide-types -fno-tree-bit-ccp -fno-tree-ccp -fno-tree-ch -fno-tree-coalesce-vars -fno-tree-copy-prop -fno-tree-dce -fno-tree-dominator-opts -fno-tree-dse -fno-tree-fre -fno-tree-phiprop -fno-tree-pta -fno-tree-scev-cprop -fno-tree-sink -fno-tree-slsr -fno-tree-sra -fno-tree-ter -fno-tree-reassoc -fPIC -fno-gnu-unique -shared"
++      c_flags = "-O0 -fPIC -shared"
+ 
+     if not s.is_default("c_flags"):
+       c_flags += f" {expand(s.c_flags)}"