diff --git a/valgrind-3.17.0-ppc64-test-isa-3-1.patch b/valgrind-3.17.0-ppc64-test-isa-3-1.patch
new file mode 100644
index 0000000..c471cdd
--- /dev/null
+++ b/valgrind-3.17.0-ppc64-test-isa-3-1.patch
@@ -0,0 +1,38 @@
+commit 60ff013998de8aa168e01b7b1c1743bcbdee99b1
+Author: Will Schmidt <will_schmidt@vnet.ibm.com>
+Date:   Thu Aug 12 15:41:50 2021 -0500
+
+    Hi
+    
+      This reworks the modulo operation as seen in
+    valgrind/none/tests/ppc64/test_isa_3_1_common.c:
+    initialize_source_registers().   Due to a GCC issue (PR101882), we
+    will try to avoid a modulo operation with both input and outputs set to
+    a hard register.
+      In this case, we can apply the modulo operation to the args[] array
+    value used to initialize the ra value.
+
+diff --git a/none/tests/ppc64/test_isa_3_1_common.c b/none/tests/ppc64/test_isa_3_1_common.c
+index 8222a857fc..7c3dc6f009 100644
+--- a/none/tests/ppc64/test_isa_3_1_common.c
++++ b/none/tests/ppc64/test_isa_3_1_common.c
+@@ -2261,12 +2261,17 @@ void initialize_source_registers () {
+       if (has_rb)  rb = 2*vrbi;
+       /* note special case for is_insert_double, see set_up_iterators () */
+       if (has_ra)  ra = 4*vrai;
+       if (is_insert_double) {
+ 	 /* For an insert_double, the results are undefined
+-	    for ra > 8, so modulo those into a valid range. */
+-	 ra = ra % 9;
++	    for ra > 8, so modulo those into a valid range.
++	    Since ra is defined as a hard register, and due to gcc
++	    issue (PR101882) where a modulo operation fails with
++	    both input and output regs set to a hard register, this
++	    assignment references the args[] array again, versus
++	    ra = ra % 9;.  */
++	 ra = args[vrai] % 9;
+       }
+    }
+ 
+    if (uses_buffer) {
+       if (has_rb) {
diff --git a/valgrind.spec b/valgrind.spec
index 786375e..fbe4607 100644
--- a/valgrind.spec
+++ b/valgrind.spec
@@ -166,6 +166,9 @@ Patch18: valgrind-3.17.0-ppc64-statfs64.patch
 # KDE#441474 vgdb might eat all memory while waiting for sigstop
 Patch19: valgrind-3.17.0-vgdb-queued-signals.patch
 
+# KDE#440906 update test_isa_3_1_common.c to avoid modulo against hard regs
+Patch20: valgrind-3.17.0-ppc64-test-isa-3-1.patch
+
 BuildRequires: make
 BuildRequires: glibc-devel
 
@@ -324,6 +327,7 @@ touch memcheck/tests/s390x/vistr.stdout.exp
 %patch17 -p1
 %patch18 -p1
 %patch19 -p1
+%patch20 -p1
 
 %build
 # LTO triggers undefined symbols in valgrind.  Valgrind has a --enable-lto
@@ -551,6 +555,7 @@ fi
 %changelog
 * Wed Aug 25 2021 Mark Wielaard <mjw@fedoraproject.org>
 - Add valgrind-3.17.0-vgdb-queued-signals.patch
+- Add valgrind-3.17.0-ppc64-test-isa-3-1.patch
 
 * Fri Aug  6 2021 Mark Wielaard <mjw@fedoraproject.org> - 3.17.0-11
 - Add valgrind-3.17.0-ppc64-statfs64.patch