[gcc r15-1889] rs6000: Consider explicit VSX when masking off ALTIVEC [PR115688]

[Kewen Lin via Gcc-cvs]

https://gcc.gnu.org/g:f90ca62566c1d20da585d95ced99f6a1903fc2cc

commit r15-1889-gf90ca62566c1d20da585d95ced99f6a1903fc2cc
Author: Kewen Lin <li...@linux.ibm.com>
Date:   Sun Jul 7 22:38:34 2024 -0500

    rs6000: Consider explicit VSX when masking off ALTIVEC [PR115688]
    
    PR115688 exposes an inconsistent state in which we have VSX
    enabled but ALTIVEC disabled.  There is one hunk:
    
      if (main_target_opt && !main_target_opt->x_rs6000_altivec_abi)
        rs6000_isa_flags &= ~((OPTION_MASK_VSX | OPTION_MASK_ALTIVEC)
                              & ~rs6000_isa_flags_explicit);
    
    which disables both VSX and ALTIVEC together only considering
    them explicitly set or not.  For the given case, VSX is explicitly
    specified, altivec is implicitly enabled as it's part of set
    ISA_2_6_MASKS_SERVER.  When falling into the above hunk, vsx is
    kept as it's explicitly enabled but altivec gets masked off, it's
    unexpected.
    
    This patch is to consider explicit VSX when masking off ALTIVEC,
    not mask off it if TARGET_VSX and it's explicitly set.
    
            PR target/115688
    
    gcc/ChangeLog:
    
            * config/rs6000/rs6000.cc (rs6000_option_override_internal): 
Consider
            explicit VSX when masking off ALTIVEC.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/powerpc/pr115688.c: New test.

Diff:
---
 gcc/config/rs6000/rs6000.cc                 |  8 ++++++--
 gcc/testsuite/gcc.target/powerpc/pr115688.c | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 58553ff66f46..2cbea6ea2d7c 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -3933,8 +3933,12 @@ rs6000_option_override_internal (bool global_init_p)
      not for 32-bit.  Don't move this before the above code using ignore_masks,
      since it can reset the cleared VSX/ALTIVEC flag again.  */
   if (main_target_opt && !main_target_opt->x_rs6000_altivec_abi)
-    rs6000_isa_flags &= ~((OPTION_MASK_VSX | OPTION_MASK_ALTIVEC)
-                         & ~rs6000_isa_flags_explicit);
+    {
+      rs6000_isa_flags &= ~(OPTION_MASK_VSX & ~rs6000_isa_flags_explicit);
+      /* Don't mask off ALTIVEC if it is enabled by an explicit VSX.  */
+      if (!TARGET_VSX)
+       rs6000_isa_flags &= ~(OPTION_MASK_ALTIVEC & ~rs6000_isa_flags_explicit);
+    }
 
   if (TARGET_CRYPTO && !TARGET_ALTIVEC)
     {
diff --git a/gcc/testsuite/gcc.target/powerpc/pr115688.c 
b/gcc/testsuite/gcc.target/powerpc/pr115688.c
new file mode 100644
index 000000000000..5222e66ef170
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr115688.c
@@ -0,0 +1,14 @@
+/* { dg-do compile { target powerpc*-*-linux* } } */
+/* { dg-options "-mdejagnu-cpu=power5 -O2" } */
+
+/* Ignore some error messages on "target attribute or
+   pragma changes AltiVec ABI".  */
+/* { dg-excess-errors "pr115688" { target ilp32 } } */
+
+/* Verify there is no ICE under 32 bit env.  */
+
+__attribute__((target("vsx")))
+int test (void)
+{
+  return 0;
+}