[gcc r10-10596] rs6000: Ignore fusion option flags for inlining test [PR102059]

[gcc r10-10596] rs6000: Ignore fusion option flags for inlining test [PR102059]

[Peter Bergner]

https://gcc.gnu.org/g:aa33a2d866c0f3f2f9b3cb26f8ff2074bcd169b4

commit r10-10596-gaa33a2d866c0f3f2f9b3cb26f8ff2074bcd169b4
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Fri May 6 11:39:13 2022 -0500

    rs6000: Ignore fusion option flags for inlining test [PR102059]
    
    The -mpower8-fusion option does not modify which instructions we can generate,
    so ignore it 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.c (rs6000_can_inline_p): Ignore -mpower8-fusion
            option for inlining purposes.
    
    gcc/testsuite/
            PR target/102059
            * gcc.target/powerpc/pr102059-4.c: New test.
    
    (cherry picked from commit 2fb654f77d5292864ef57040f7bc01d7a975f6d9)

Diff:
---
 gcc/config/rs6000/rs6000.c                    |  4 ++++
 gcc/testsuite/gcc.target/powerpc/pr102059-4.c | 23 +++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index e95d877f866..4ea0e73594d 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -24477,6 +24477,10 @@ rs6000_can_inline_p (tree caller, tree callee)
       else
 	caller_isa = rs6000_isa_flags;
 
+      /* Ignore the -mpower8-fusion option for inlining purposes.  */
+      callee_isa &= ~OPTION_MASK_P8_FUSION;
+      explicit_isa &= ~OPTION_MASK_P8_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 00000000000..5fe66f8af4b
--- /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;
+}