diff --git a/src/util/register_allocate.c b/src/util/register_allocate.c
index e44c509643a..8c3296c342e 100644
--- a/src/util/register_allocate.c
+++ b/src/util/register_allocate.c
@@ -282,6 +282,21 @@ ra_class_add_reg(struct ra_class *class, unsigned int r)
    class->p++;
 }
 
+/**
+ * Overrides the P value of a register class to be below the
+ * automatically calculated one in order to force optimistic
+ * allocation above this threshold even for nodes that are trivially
+ * colorable, which can be used to reduce the register requirement of
+ * programs on platforms where increasing register use imposes limits
+ * on thread parallelism.
+ */
+void
+ra_class_override_p(struct ra_class *class, unsigned int p)
+{
+   assert(p <= class->p);
+   class->p = p;
+}
+
 /**
  * Returns true if the register belongs to the given class.
  */
diff --git a/src/util/register_allocate.h b/src/util/register_allocate.h
index 14f2be4023a..d580fb249fe 100644
--- a/src/util/register_allocate.h
+++ b/src/util/register_allocate.h
@@ -67,6 +67,7 @@ ra_add_transitive_reg_pair_conflict(struct ra_regs *regs,
 
 void ra_make_reg_conflicts_transitive(struct ra_regs *regs, unsigned int reg);
 void ra_class_add_reg(struct ra_class *c, unsigned int reg);
+void ra_class_override_p(struct ra_class *c, unsigned int p);
 struct ra_class *ra_get_class_from_index(struct ra_regs *regs, unsigned int c);
 void ra_set_finalize(struct ra_regs *regs, unsigned int **conflicts);