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.

2 files changed, 28 insertions, 0 deletions

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index bc61959..4030864 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/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
diff --git a/gcc/testsuite/gcc.target/powerpc/pr102059-4.c b/gcc/testsuite/gcc.target/powerpc/pr102059-4.c
new file mode 100644
index 0000000..5fe66f8
--- /dev/null
+++ b/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;
+}