rs6000: Ignore fusion option flags for inlining test [PR102059]

The -mpower8-fusion and -mpower10-fusion options do not modify which
instructions we can generate, so ignore them when deciding whether we
can inline callee into caller.

2022-05-06   Michael Meissner  <meissner@linux.ibm.com>

gcc/
	PR target/102059
	* config/rs6000/rs6000.cc (rs6000_can_inline_p): Ignore -mpower8-fusion
	and -mpower10-fusion options for inlining purposes.

gcc/testsuite/
	PR target/102059
	* gcc.target/powerpc/pr102059-4.c: New test.

(cherry picked from commit 2fb654f77d)

gcc/config/rs6000/rs6000.cc

@@ -25350,6 +25350,11 @@ rs6000_can_inline_p (tree caller, tree callee)
 	    }
 	}
 
+      /* Ignore -mpower8-fusion and -mpower10-fusion options for inlining
+	 purposes.  */
+      callee_isa &= ~(OPTION_MASK_P8_FUSION | OPTION_MASK_P10_FUSION);
+      explicit_isa &= ~(OPTION_MASK_P8_FUSION | OPTION_MASK_P10_FUSION);
+
       /* The callee's options must be a subset of the caller's options, i.e.
 	 a vsx function may inline an altivec function, but a no-vsx function
 	 must not inline a vsx function.  However, for those options that the

gcc/testsuite/gcc.target/powerpc/pr102059-4.c

@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mdejagnu-cpu=power10" } */
+/* { dg-require-effective-target power10_ok } */
+
+/* Verify that power10 can explicity include functions compiled for power8.
+   The issue was -mcpu=power8 enables -mpower8-fusion, but -mcpu=power9 or
+   -mcpu=power10 do not set power8-fusion by default.  Thus when doing this
+   compilation, they would get an error that the inline function failed in its
+   inlining due to having incompatible options.  */
+
+static inline int __attribute__ ((always_inline,target("cpu=power8")))
+foo (int *b)
+{
+  *b += 10;
+  return *b;
+}
+
+int
+bar (int *a)
+{
+  *a = foo (a);
+  return 0;
+}