[RS6000] Don't pass -many to the assembler

I'd like to remove -many from the options passed by default to the
assembler, on the grounds that a gcc bug in instruction selection (eg.
emitting a power9 insn for -mcpu=power8) is better found at assembly
time than run time.

For now, just do this when --enable-checking or gcc is not a release.

This patch also emits .machine assembler directives for ELF targets
when functions are compiled for different cpus via attributes or
pragmas.  That's necessary when the initial -m<cpu> option passed to
the assembler doesn't enable the superset of all opcodes emitted, as
seen by a failure of gcc.target/powerpc/clone2.c without .machine
when building gcc for power8.

rs6000_machine_from_flags deliberately uses ISA_2_4_MASKS rather than
ISA_2_2_MASKS for power5 because "friz" and other similar instructions
enabled by gcc with TARGET_FPRND are enabled in gas by "-mpower5".
(gas -mpower5 supports power5+ too.)  rs6000-cpus.def puts
OPTION_MASK_FPRND in ISA_2_4_MASKS, so ISA_2_4_MASKS is the one to use
in deciding to pass "-mpower5" to gas.

O3-pr70130.c also failed on an earlier version of this patch (when
only testing one ISA bit to determine .machine).  This is a test for a
power7 vector bug, but on power8 hw check_vect_support_and_set_flags
passes -mpower8-vector which means the test isn't exercising the
original bug exactly.  I reckon that is wrong, and similary for other
vector testcases that ask for a specific cpu.  I've fixed it here by
explicitly passing -mno-power8-vector and similar vector options.

	* config/rs6000/rs6000.h (ASM_OPT_ANY): Define.
	(ASM_CPU_SPEC): Conditionally add -many.
	* config/rs6000/rs6000.c (rs6000_machine): New static var.
	(rs6000_machine_from_flags, emit_asm_machine): New functions..
	(rs6000_file_start): ..extracted from here, and modified to
	test all ISA bits.
	(rs6000_output_function_prologue): Emit .machine as necessary.
	* testsuite/gcc.target/powerpc/ppc32-abi-dfp-1.c: Don't use
	power mnemonics.
	* testsuite/gcc.dg/vect/O3-pr70130.c: Disable default options
	added by check_vect_support_and_set_flags.
	* testsuite/gcc.dg/vect/pr48765.c: Likewise.
	* testsuite/gfortran.dg/vect/pr45714-b.f: Likewise.

From-SVN: r271500

Author: amodra

gcc/ChangeLog

@@ -1,3 +1,19 @@
+2019-05-22  Alan Modra  <amodra@gmail.com>
+
+	* config/rs6000/rs6000.h (ASM_OPT_ANY): Define.
+	(ASM_CPU_SPEC): Conditionally add -many.
+	* config/rs6000/rs6000.c (rs6000_machine): New static var.
+	(rs6000_machine_from_flags, emit_asm_machine): New functions..
+	(rs6000_file_start): ..extracted from here, and modified to
+	test all ISA bits.
+	(rs6000_output_function_prologue): Emit .machine as necessary.
+	* testsuite/gcc.target/powerpc/ppc32-abi-dfp-1.c: Don't use
+	power mnemonics.
+	* testsuite/gcc.dg/vect/O3-pr70130.c: Disable default options
+	added by check_vect_support_and_set_flags.
+	* testsuite/gcc.dg/vect/pr48765.c: Likewise.
+	* testsuite/gfortran.dg/vect/pr45714-b.f: Likewise.
+
 2019-05-22  Hans-Peter Nilsson  <hp@axis.com>
 
 	PR middle-end/90553

gcc/config/rs6000/rs6000.c

@@ -5632,6 +5632,36 @@ rs6000_builtin_md_vectorized_function (tree fndecl, tree type_out,
 /* Default CPU string for rs6000*_file_start functions.  */
 static const char *rs6000_default_cpu;
 
+#ifdef USING_ELFOS_H
+static const char *rs6000_machine;
+
+static const char *
+rs6000_machine_from_flags (void)
+{
+  if ((rs6000_isa_flags & (ISA_3_0_MASKS_SERVER & ~ISA_2_7_MASKS_SERVER)) != 0)
+    return "power9";
+  if ((rs6000_isa_flags & (ISA_2_7_MASKS_SERVER & ~ISA_2_6_MASKS_SERVER)) != 0)
+    return "power8";
+  if ((rs6000_isa_flags & (ISA_2_6_MASKS_SERVER & ~ISA_2_5_MASKS_SERVER)) != 0)
+    return "power7";
+  if ((rs6000_isa_flags & (ISA_2_5_MASKS_SERVER & ~ISA_2_4_MASKS)) != 0)
+    return "power6";
+  if ((rs6000_isa_flags & (ISA_2_4_MASKS & ~ISA_2_1_MASKS)) != 0)
+    return "power5";
+  if ((rs6000_isa_flags & ISA_2_1_MASKS) != 0)
+    return "power4";
+  if ((rs6000_isa_flags & OPTION_MASK_POWERPC64) != 0)
+    return "ppc64";
+  return "ppc";
+}
+
+static void
+emit_asm_machine (void)
+{
+  fprintf (asm_out_file, "\t.machine %s\n", rs6000_machine);
+}
+#endif
+
 /* Do anything needed at the start of the asm file.  */
 
 static void
@@ -5697,27 +5727,10 @@ rs6000_file_start (void)
     }
 
 #ifdef USING_ELFOS_H
+  rs6000_machine = rs6000_machine_from_flags ();
   if (!(rs6000_default_cpu && rs6000_default_cpu[0])
       && !global_options_set.x_rs6000_cpu_index)
-    {
-      fputs ("\t.machine ", asm_out_file);
-      if ((rs6000_isa_flags & OPTION_MASK_MODULO) != 0)
-	fputs ("power9\n", asm_out_file);
-      else if ((rs6000_isa_flags & OPTION_MASK_DIRECT_MOVE) != 0)
-	fputs ("power8\n", asm_out_file);
-      else if ((rs6000_isa_flags & OPTION_MASK_POPCNTD) != 0)
-	fputs ("power7\n", asm_out_file);
-      else if ((rs6000_isa_flags & OPTION_MASK_CMPB) != 0)
-	fputs ("power6\n", asm_out_file);
-      else if ((rs6000_isa_flags & OPTION_MASK_POPCNTB) != 0)
-	fputs ("power5\n", asm_out_file);
-      else if ((rs6000_isa_flags & OPTION_MASK_MFCRF) != 0)
-	fputs ("power4\n", asm_out_file);
-      else if ((rs6000_isa_flags & OPTION_MASK_POWERPC64) != 0)
-	fputs ("ppc64\n", asm_out_file);
-      else
-	fputs ("ppc\n", asm_out_file);
-    }
+    emit_asm_machine ();
 #endif
 
   if (DEFAULT_ABI == ABI_ELFv2)
@@ -27504,7 +27517,17 @@ static void
 rs6000_output_function_prologue (FILE *file)
 {
   if (!cfun->is_thunk)
-    rs6000_output_savres_externs (file);
+    {
+      rs6000_output_savres_externs (file);
+#ifdef USING_ELFOS_H
+      const char *curr_machine = rs6000_machine_from_flags ();
+      if (rs6000_machine != curr_machine)
+	{
+	  rs6000_machine = curr_machine;
+	  emit_asm_machine ();
+	}
+#endif
+    }
 
   /* ELFv2 ABI r2 setup code and local entry point.  This must follow
      immediately after the global entry point label.  */

gcc/config/rs6000/rs6000.h

@@ -70,6 +70,12 @@
 #define PPC405_ERRATUM77 0
 #endif
 
+#if CHECKING_P
+#define ASM_OPT_ANY ""
+#else
+#define ASM_OPT_ANY " -many"
+#endif
+
 /* Common ASM definitions used by ASM_SPEC among the various targets for
    handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.c to
    provide the default assembler options if the user uses -mcpu=native, so if
@@ -137,8 +143,8 @@
 	    mvsx: -mpower7; \
 	    mpowerpc64: -mppc64;: %(asm_default)}; \
   :%eMissing -mcpu option in ASM_CPU_SPEC?\n} \
-%{mvsx: -mvsx -maltivec; maltivec: -maltivec} \
--many"
+%{mvsx: -mvsx -maltivec; maltivec: -maltivec}" \
+ASM_OPT_ANY
 
 #define CPP_DEFAULT_SPEC ""
 

gcc/testsuite/gcc.dg/vect/O3-pr70130.c

@@ -1,5 +1,5 @@
 /* { dg-require-effective-target vsx_hw { target powerpc*-*-* } } */
-/* { dg-additional-options "-mcpu=power7" { target powerpc*-*-* } } */
+/* { dg-additional-options "-mcpu=power7 -mno-power9-vector -mno-power8-vector" { target powerpc*-*-* } } */
 
 #include "tree-vect.h"
 

gcc/testsuite/gcc.dg/vect/pr48765.c

@@ -1,6 +1,6 @@
 /* { dg-do compile { target { powerpc*-*-* } } } */
 /* { dg-skip-if "do not override -mcpu" { *-*-* } { "-mcpu=*" } { "-mcpu=power6" } } */
-/* { dg-additional-options "-O3 -mcpu=power6" } */
+/* { dg-additional-options "-O3 -mcpu=power6 -mno-power9-vector -mno-power8-vector -mno-vsx" } */
 
 enum reg_class
 {

gcc/testsuite/gcc.target/powerpc/ppc32-abi-dfp-1.c

@@ -45,14 +45,14 @@ __asm__ ("\t.globl\t" #NAME "_asm\n\t"					\
 	 #NAME "_asm:\n\t"						\
 	 "lis 11,gparms@ha\n\t"						\
 	 "la 11,gparms@l(11)\n\t"					\
-	 "st 3,0(11)\n\t"						\
-	 "st 4,4(11)\n\t"						\
-	 "st 5,8(11)\n\t"						\
-	 "st 6,12(11)\n\t"						\
-	 "st 7,16(11)\n\t"						\
-	 "st 8,20(11)\n\t"						\
-	 "st 9,24(11)\n\t"						\
-	 "st 10,28(11)\n\t"						\
+	 "stw 3,0(11)\n\t"						\
+	 "stw 4,4(11)\n\t"						\
+	 "stw 5,8(11)\n\t"						\
+	 "stw 6,12(11)\n\t"						\
+	 "stw 7,16(11)\n\t"						\
+	 "stw 8,20(11)\n\t"						\
+	 "stw 9,24(11)\n\t"						\
+	 "stw 10,28(11)\n\t"						\
 	 "stfd 1,32(11)\n\t"						\
 	 "stfd 2,40(11)\n\t"						\
 	 "stfd 3,48(11)\n\t"						\

gcc/testsuite/gfortran.dg/vect/pr45714-b.f

@@ -1,5 +1,5 @@
 ! { dg-do compile { target powerpc*-*-* } }
-! { dg-additional-options "-O3 -mcpu=power7 -ffast-math -mveclibabi=mass" }
+! { dg-additional-options "-O3 -mcpu=power7 -mno-power9-vector -mno-power8-vector -ffast-math -mveclibabi=mass" }
 
       integer index(18),i,j,k,l,ipiv(18),info,ichange,neq,lda,ldb,
      &  nrhs,iplas