From b525a0280a4630cd3d4347c2d2f545b54e6077c2 Mon Sep 17 00:00:00 2001
From: Alain Dargelas <alain@silimate.com>
Date: Thu, 19 Dec 2024 14:08:37 -0800
Subject: [PATCH] Move helper code to peepopt.cc, check offset

---
 passes/pmgen/peepopt.cc           | 12 ++++++++++++
 passes/pmgen/peepopt_muldiv_c.pmg |  2 +-
 passes/pmgen/pmgen.py             |  7 -------
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/passes/pmgen/peepopt.cc b/passes/pmgen/peepopt.cc
index e7a729ecb..fe4fc89e0 100644
--- a/passes/pmgen/peepopt.cc
+++ b/passes/pmgen/peepopt.cc
@@ -28,6 +28,9 @@ bool did_something;
 // scratchpad configurations for pmgen
 int shiftadd_max_ratio;
 
+// Helper function, removes LSB 0s
+SigSpec remove_bottom_padding(SigSpec sig);
+
 #include "passes/pmgen/peepopt_pm.h"
 
 struct PeepoptPass : public Pass {
@@ -117,4 +120,13 @@ struct PeepoptPass : public Pass {
 	}
 } PeepoptPass;
 
+
+SigSpec remove_bottom_padding(SigSpec sig)
+{
+	int i = 0;
+	for (; i < sig.size() - 1 && sig[i] == State::S0; i++) {
+	}
+	return sig.extract(i, sig.size() - i);
+}
+
 PRIVATE_NAMESPACE_END
diff --git a/passes/pmgen/peepopt_muldiv_c.pmg b/passes/pmgen/peepopt_muldiv_c.pmg
index fff4ad2a9..5841d396e 100644
--- a/passes/pmgen/peepopt_muldiv_c.pmg
+++ b/passes/pmgen/peepopt_muldiv_c.pmg
@@ -60,7 +60,7 @@ code
 		reject;
 	if (b_const.size() > 64)
 		reject;
-	if (c_const.size() > 64)
+	if (c_const.size() + offset > 64)
 		reject;
 
 	// Check for potential mult overflow
diff --git a/passes/pmgen/pmgen.py b/passes/pmgen/pmgen.py
index b07612f50..6e2fabeeb 100644
--- a/passes/pmgen/pmgen.py
+++ b/passes/pmgen/pmgen.py
@@ -429,13 +429,6 @@ with open(outfile, "w") as f:
     print("  }", file=f)
     print("", file=f)
 
-    print("  SigSpec remove_bottom_padding(SigSpec sig) {", file=f)
-    print("    int i = 0;", file=f)
-    print("    for (; i < sig.size() - 1 && sig[i] == State::S0; i++) {} ", file=f)
-    print("    return sig.extract(i, sig.size() - i);", file=f)
-    print("  }", file=f)
-    print("", file=f)
-
     print("  void blacklist(Cell *cell) {", file=f)
     print("    if (cell != nullptr && blacklist_cells.insert(cell).second) {", file=f)
     print("      auto ptr = rollback_cache.find(cell);", file=f)