rs6000: Fix .machine cpu selection w/ altivec [PR97367]

There are various non-IBM CPUs with altivec, so we cannot use that
flag to determine which .machine cpu to use, so ignore it.
Emit an additional ".machine altivec" if Altivec is enabled so
that the assembler doesn't require an explicit -maltivec option
to assemble any Altivec instructions for those targets where
the ".machine cpu" is insufficient to enable Altivec.  For example,
-mcpu=G5 emits a ".machine power4".

2024-07-18  René Rebe  <rene@exactcode.de>
	    Peter Bergner  <bergner@linux.ibm.com>

gcc/
	PR target/97367
	* config/rs6000/rs6000.cc (rs6000_machine_from_flags): Do not consider
	OPTION_MASK_ALTIVEC.
	(emit_asm_machine): For Altivec compiles, emit a ".machine altivec".

gcc/testsuite/
	PR target/97367
	* gcc.target/powerpc/pr97367.c: New test.

Signed-off-by: René Rebe <rene@exactcode.de>

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 2c0a7fc8cefa728e85effe943e6de2010c2abb02..5ed64b1e68666f40d2bb88498707b9ef5f871f14 100644 (file)
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -5896,7 +5896,8 @@ rs6000_machine_from_flags (void)
   HOST_WIDE_INT flags = rs6000_isa_flags;
 
   /* Disable the flags that should never influence the .machine selection.  */
-  flags &= ~(OPTION_MASK_PPC_GFXOPT | OPTION_MASK_PPC_GPOPT | OPTION_MASK_ISEL);
+  flags &= ~(OPTION_MASK_PPC_GFXOPT | OPTION_MASK_PPC_GPOPT | OPTION_MASK_ISEL
+            | OPTION_MASK_ALTIVEC);
 
   if ((flags & (ISA_3_1_MASKS_SERVER & ~ISA_3_0_MASKS_SERVER)) != 0)
     return "power10";
@@ -5921,6 +5922,8 @@ void
 emit_asm_machine (void)
 {
   fprintf (asm_out_file, "\t.machine %s\n", rs6000_machine);
+  if (TARGET_ALTIVEC)
+    fprintf (asm_out_file, "\t.machine altivec\n");
 }
 #endif
 

diff --git a/gcc/testsuite/gcc.target/powerpc/pr97367.c b/gcc/testsuite/gcc.target/powerpc/pr97367.c
new file mode 100644 (file)
index 0000000..ef269a5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr97367.c
@@ -0,0 +1,13 @@
+/* PR target/97367 */
+/* { dg-options "-mdejagnu-cpu=G5" } */
+
+/* Verify we emit a ".machine power4" and ".machine altivec" rather
+   than a ".machine power7".  */
+
+int dummy (void)
+{
+  return 0;
+}
+
+/* { dg-final { scan-assembler {\.machine power4\M} } } */
+/* { dg-final { scan-assembler {\.machine altivec\M} } } */