diff --git a/Changes b/Changes
index cc6966a12..4f3de61d1 100644
--- a/Changes
+++ b/Changes
@@ -9,7 +9,7 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ***   Support SV 2012 package import before port list.
 
-****  Fix huge shifts to zero with -Wno-WIDTH, bug765, bug766, bug768. [Clifford Wolf]
+****  Fix shift corner issues, bug765, bug766, bug768, bug772. [Clifford Wolf]
 
 ****  Fix gate primitives with arrays and non-arrayed pins.
 
diff --git a/src/V3Const.cpp b/src/V3Const.cpp
index 60222415d..f7bdffc5a 100644
--- a/src/V3Const.cpp
+++ b/src/V3Const.cpp
@@ -274,6 +274,8 @@ private:
 	// We can only get rid of a<<b>>c or a<<b<<c, with constant b & c
 	// because bits may be masked in that process, or (b+c) may exceed the word width.
 	if (!(nodep->rhsp()->castConst() && lhsp->rhsp()->castConst())) return false;
+	if (nodep->rhsp()->castConst()->num().isFourState()
+	    || lhsp->rhsp()->castConst()->num().isFourState()) return false;
 	if (nodep->width()!=lhsp->width()) return false;
 	if (nodep->width()!=lhsp->lhsp()->width()) return false;
 	return true;
diff --git a/test_regress/t/t_math_signed5.v b/test_regress/t/t_math_signed5.v
index 0222e048e..26740b20f 100644
--- a/test_regress/t/t_math_signed5.v
+++ b/test_regress/t/t_math_signed5.v
@@ -133,6 +133,12 @@
       w4_u = $signed(5'd1 > w4_s-w4_s);
       `checkh(w4_u, 4'b1111);
 
+      // bug772
+      w4_s = w4_u << 1 <<< 0/0;
+`ifndef VERILATOR       // In v4 can't check value as not 4-state
+      `checkh(w4_s, 4'bxxxx);
+`endif
+
       if (fail) $stop;
       $write("*-* All Finished *-*\n");
       $finish;