[gcc(refs/users/wschmidt/heads/builtins10)] rs6000: Builtin expansion, part 3

[William Schmidt <wschmidt@gcc.gnu.org>]

https://gcc.gnu.org/g:4e58efc0dd39d2516c7ce58cc2bef55f30b187ce

commit 4e58efc0dd39d2516c7ce58cc2bef55f30b187ce
Author: Bill Schmidt <wschmidt@linux.ibm.com>
Date:   Fri Mar 5 13:07:00 2021 -0600

    rs6000: Builtin expansion, part 3
    
    2021-03-05  Bill Schmidt  <wschmidt@linux.ibm.com>
    
    gcc/
            * config/rs6000/rs6000-call.c (new_cpu_expand_builtin):
            Implement.

Diff:
---
 gcc/config/rs6000/rs6000-call.c | 100 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)

diff --git a/gcc/config/rs6000/rs6000-call.c b/gcc/config/rs6000/rs6000-call.c
index 87b8698c9f5..a568682592c 100644
--- a/gcc/config/rs6000/rs6000-call.c
+++ b/gcc/config/rs6000/rs6000-call.c
@@ -14480,6 +14480,106 @@ static rtx
 new_cpu_expand_builtin (enum rs6000_gen_builtins fcode,
 			tree exp ATTRIBUTE_UNUSED, rtx target)
 {
+  /* __builtin_cpu_init () is a nop, so expand to nothing.  */
+  if (fcode == RS6000_BIF_CPU_INIT)
+    return const0_rtx;
+
+  if (target == 0 || GET_MODE (target) != SImode)
+    target = gen_reg_rtx (SImode);
+
+#ifdef TARGET_LIBC_PROVIDES_HWCAP_IN_TCB
+  tree arg = TREE_OPERAND (CALL_EXPR_ARG (exp, 0), 0);
+  /* Target clones creates an ARRAY_REF instead of STRING_CST, convert it back
+     to a STRING_CST.  */
+  if (TREE_CODE (arg) == ARRAY_REF
+      && TREE_CODE (TREE_OPERAND (arg, 0)) == STRING_CST
+      && TREE_CODE (TREE_OPERAND (arg, 1)) == INTEGER_CST
+      && compare_tree_int (TREE_OPERAND (arg, 1), 0) == 0)
+    arg = TREE_OPERAND (arg, 0);
+
+  if (TREE_CODE (arg) != STRING_CST)
+    {
+      error ("builtin %qs only accepts a string argument",
+	     rs6000_builtin_info_x[(size_t) fcode].bifname);
+      return const0_rtx;
+    }
+
+  if (fcode == RS6000_BIF_CPU_IS)
+    {
+      const char *cpu = TREE_STRING_POINTER (arg);
+      rtx cpuid = NULL_RTX;
+      for (size_t i = 0; i < ARRAY_SIZE (cpu_is_info); i++)
+	if (strcmp (cpu, cpu_is_info[i].cpu) == 0)
+	  {
+	    /* The CPUID value in the TCB is offset by _DL_FIRST_PLATFORM.  */
+	    cpuid = GEN_INT (cpu_is_info[i].cpuid + _DL_FIRST_PLATFORM);
+	    break;
+	  }
+      if (cpuid == NULL_RTX)
+	{
+	  /* Invalid CPU argument.  */
+	  error ("cpu %qs is an invalid argument to builtin %qs",
+		 cpu, rs6000_builtin_info_x[(size_t) fcode].bifname);
+	  return const0_rtx;
+	}
+
+      rtx platform = gen_reg_rtx (SImode);
+      rtx tcbmem = gen_const_mem (SImode,
+				  gen_rtx_PLUS (Pmode,
+						gen_rtx_REG (Pmode, TLS_REGNUM),
+						GEN_INT (TCB_PLATFORM_OFFSET)));
+      emit_move_insn (platform, tcbmem);
+      emit_insn (gen_eqsi3 (target, platform, cpuid));
+    }
+  else if (fcode == RS6000_BIF_CPU_SUPPORTS)
+    {
+      const char *hwcap = TREE_STRING_POINTER (arg);
+      rtx mask = NULL_RTX;
+      int hwcap_offset;
+      for (size_t i = 0; i < ARRAY_SIZE (cpu_supports_info); i++)
+	if (strcmp (hwcap, cpu_supports_info[i].hwcap) == 0)
+	  {
+	    mask = GEN_INT (cpu_supports_info[i].mask);
+	    hwcap_offset = TCB_HWCAP_OFFSET (cpu_supports_info[i].id);
+	    break;
+	  }
+      if (mask == NULL_RTX)
+	{
+	  /* Invalid HWCAP argument.  */
+	  error ("%s %qs is an invalid argument to builtin %qs",
+		 "hwcap", hwcap,
+		 rs6000_builtin_info_x[(size_t) fcode].bifname);
+	  return const0_rtx;
+	}
+
+      rtx tcb_hwcap = gen_reg_rtx (SImode);
+      rtx tcbmem = gen_const_mem (SImode,
+				  gen_rtx_PLUS (Pmode,
+						gen_rtx_REG (Pmode, TLS_REGNUM),
+						GEN_INT (hwcap_offset)));
+      emit_move_insn (tcb_hwcap, tcbmem);
+      rtx scratch1 = gen_reg_rtx (SImode);
+      emit_insn (gen_rtx_SET (scratch1, gen_rtx_AND (SImode, tcb_hwcap, mask)));
+      rtx scratch2 = gen_reg_rtx (SImode);
+      emit_insn (gen_eqsi3 (scratch2, scratch1, const0_rtx));
+      emit_insn (gen_rtx_SET (target, gen_rtx_XOR (SImode, scratch2, const1_rtx)));
+    }
+  else
+    gcc_unreachable ();
+
+  /* Record that we have expanded a CPU builtin, so that we can later
+     emit a reference to the special symbol exported by LIBC to ensure we
+     do not link against an old LIBC that doesn't support this feature.  */
+  cpu_builtin_p = true;
+
+#else
+  warning (0, "builtin %qs needs GLIBC (2.23 and newer) that exports hardware "
+	   "capability bits", rs6000_builtin_info_x[(size_t) fcode].bifname);
+
+  /* For old LIBCs, always return FALSE.  */
+  emit_move_insn (target, GEN_INT (0));
+#endif /* TARGET_LIBC_PROVIDES_HWCAP_IN_TCB */
+
   return target;
 }