[PATCH v2] rs6000: ICE when using an MMA type as a function param or return value [PR96506]

Peter Bergner bergner@linux.ibm.com
Wed Aug 12 20:32:18 GMT 2020


rs6000: ICE when using an MMA type as a function param or return value [PR96506]

PR96506 shows a problem where we ICE on illegal usage, namely using MMA
types for function arguments and return values.  The solution is to flag
these illegal usages as errors early, before we ICE.

The patch below is functionally identical to the previous patch.
The differences are that I've added more comments around the use of the
static local variable and I added prototypes for the test case's extern
bar* functions which allowed me to remove the now unneeded -w option.

Ok for trunk now?  Ok for GCC 10 after some bake in?

Peter


gcc/
	PR target/96506
	* config/rs6000/rs6000-call.c (rs6000_promote_function_mode): Disallow
	MMA types as return values.
	(rs6000_function_arg): Disallow MMA types as function arguments.

gcc/testsuite/
	PR target/96506
	* gcc.target/powerpc/pr96506.c: New test.

diff --git a/gcc/config/rs6000/rs6000-call.c b/gcc/config/rs6000/rs6000-call.c
index 189497efb45..869e4973a16 100644
--- a/gcc/config/rs6000/rs6000-call.c
+++ b/gcc/config/rs6000/rs6000-call.c
@@ -6444,8 +6444,26 @@ machine_mode
 rs6000_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
 			      machine_mode mode,
 			      int *punsignedp ATTRIBUTE_UNUSED,
-			      const_tree, int)
+			      const_tree, int for_return)
 {
+  /* Warning: this is a static local variable and not always NULL!  */
+  static struct function *fn = NULL;
+
+  /* We do not allow MMA types being used as return values.  Only report
+     the invalid return value usage the first time we encounter it.  */
+  if (for_return
+      && fn != cfun
+      && (mode == POImode || mode == PXImode))
+    {
+      /* Record we have now handled function CFUN, so the next time we
+	 are called, we do not re-report the same error.  */
+      fn = cfun;
+      if (TYPE_CANONICAL (type) != NULL_TREE)
+	type = TYPE_CANONICAL (type);
+      error ("invalid use of MMA type %qs as a function return value",
+	     IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type))));
+    }
+
   PROMOTE_MODE (mode, *punsignedp, type);
 
   return mode;
@@ -7396,6 +7414,16 @@ rs6000_function_arg (cumulative_args_t cum_v, const function_arg_info &arg)
   machine_mode elt_mode;
   int n_elts;
 
+  /* We do not allow MMA types being used as function arguments.  */
+  if (mode == POImode || mode == PXImode)
+    {
+      if (TYPE_CANONICAL (type) != NULL_TREE)
+	type = TYPE_CANONICAL (type);
+      error ("invalid use of MMA operand of type %qs as a function parameter",
+	     IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type))));
+      return NULL_RTX;
+    }
+
   /* Return a marker to indicate whether CR1 needs to set or clear the
      bit that V.4 uses to say fp args were passed in registers.
      Assume that we don't need the marker for software floating point,
diff --git a/gcc/testsuite/gcc.target/powerpc/pr96506.c b/gcc/testsuite/gcc.target/powerpc/pr96506.c
new file mode 100644
index 00000000000..b1b40c5a5c8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr96506.c
@@ -0,0 +1,66 @@
+/* PR target/96506 */
+/* { dg-do compile } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2" } */
+
+extern void bar0();
+extern void bar1();
+extern void bar2();
+extern void bar3();
+
+typedef __vector_pair vpair_t;
+typedef __vector_quad vquad_t;
+
+/* Verify we flag errors on the following.  */
+
+void
+foo0 (void)
+{
+  __vector_pair v;
+  bar0 (v); /* { dg-error "invalid use of MMA operand of type .__vector_pair. as a function parameter" } */
+}
+
+void
+foo1 (void)
+{
+  vpair_t v;
+  bar1 (v); /* { dg-error "invalid use of MMA operand of type .__vector_pair. as a function parameter" } */
+}
+
+void
+foo2 (void)
+{
+  __vector_quad v;
+  bar2 (v); /* { dg-error "invalid use of MMA operand of type .__vector_quad. as a function parameter" } */
+}
+
+void
+foo3 (void)
+{
+  vquad_t v;
+  bar3 (v); /* { dg-error "invalid use of MMA operand of type .__vector_quad. as a function parameter" } */
+}
+
+__vector_pair
+foo4 (__vector_pair *src) /* { dg-error "invalid use of MMA type .__vector_pair. as a function return value" } */
+{
+  return *src;
+}
+
+vpair_t
+foo5 (vpair_t *src) /* { dg-error "invalid use of MMA type .__vector_pair. as a function return value" } */
+{
+  return *src;
+}
+
+__vector_quad
+foo6 (__vector_quad *src) /* { dg-error "invalid use of MMA type .__vector_quad. as a function return value" } */
+{
+  return *src;
+}
+
+vquad_t
+foo7 (vquad_t *src) /* { dg-error "invalid use of MMA type .__vector_quad. as a function return value" } */
+{
+  return *src;
+}



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