x86-64: Find a scratch register for large model profiling

2 scratch registers, %r10 and %r11, are available at function entry for
large model profiling.  But %r10 may be used by stack realignment and we
can't use %r10 in this case.  Add x86_64_select_profile_regnum to find
a caller-saved register which isn't live or a callee-saved register
which has been saved on stack in the prologue at entry for large model
profiling and sorry if we can't find one.

gcc/

	PR target/113689
	* config/i386/i386.cc (x86_64_select_profile_regnum): New.
	(x86_function_profiler): Call x86_64_select_profile_regnum to
	get a scratch register for large model profiling.

gcc/testsuite/

	PR target/113689
	* gcc.target/i386/pr113689-1.c: New file.
	* gcc.target/i386/pr113689-2.c: Likewise.
	* gcc.target/i386/pr113689-3.c: Likewise.

Author: hjl-tools

gcc/config/i386/i386.cc

@@ -22749,6 +22749,48 @@ current_fentry_section (const char **name)
   return true;
 }
 
+/* Return a caller-saved register which isn't live or a callee-saved
+   register which has been saved on stack in the prologue at entry for
+   profile.  */
+
+static int
+x86_64_select_profile_regnum (bool r11_ok ATTRIBUTE_UNUSED)
+{
+  /* Use %r10 if the profiler is emitted before the prologue or it isn't
+     used by DRAP.  */
+  if (ix86_profile_before_prologue ()
+      || !crtl->drap_reg
+      || REGNO (crtl->drap_reg) != R10_REG)
+    return R10_REG;
+
+  /* The profiler is emitted after the prologue.  If there is a
+     caller-saved register which isn't live or a callee-saved
+     register saved on stack in the prologue, use it.  */
+
+  bitmap reg_live = df_get_live_out (ENTRY_BLOCK_PTR_FOR_FN (cfun));
+
+  int i;
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    if (GENERAL_REGNO_P (i)
+	&& i != R10_REG
+#ifdef NO_PROFILE_COUNTERS
+	&& (r11_ok || i != R11_REG)
+#else
+	&& i != R11_REG
+#endif
+	&& TEST_HARD_REG_BIT (accessible_reg_set, i)
+	&& (ix86_save_reg (i, true, true)
+	    || (call_used_regs[i]
+		&& !fixed_regs[i]
+		&& !REGNO_REG_SET_P (reg_live, i))))
+      return i;
+
+  sorry ("no register available for profiling %<-mcmodel=large%s%>",
+	 ix86_cmodel == CM_LARGE_PIC ? " -fPIC" : "");
+
+  return INVALID_REGNUM;
+}
+
 /* Output assembler code to FILE to increment profiler label # LABELNO
    for profiling a function entry.  */
 void
@@ -22783,42 +22825,61 @@ x86_function_profiler (FILE *file, int labelno ATTRIBUTE_UNUSED)
 	fprintf (file, "\tleaq\t%sP%d(%%rip), %%r11\n", LPREFIX, labelno);
 #endif
 
+      int scratch;
+      const char *reg;
+      char legacy_reg[4] = { 0 };
+
       if (!TARGET_PECOFF)
 	{
 	  switch (ix86_cmodel)
 	    {
 	    case CM_LARGE:
-	      /* NB: R10 is caller-saved.  Although it can be used as a
-		 static chain register, it is preserved when calling
-		 mcount for nested functions.  */
+	      scratch = x86_64_select_profile_regnum (true);
+	      reg = hi_reg_name[scratch];
+	      if (LEGACY_INT_REGNO_P (scratch))
+		{
+		  legacy_reg[0] = 'r';
+		  legacy_reg[1] = reg[0];
+		  legacy_reg[2] = reg[1];
+		  reg = legacy_reg;
+		}
 	      if (ASSEMBLER_DIALECT == ASM_INTEL)
-		fprintf (file, "1:\tmovabs\tr10, OFFSET FLAT:%s\n"
-			       "\tcall\tr10\n", mcount_name);
+		fprintf (file, "1:\tmovabs\t%s, OFFSET FLAT:%s\n"
+			       "\tcall\t%s\n", reg, mcount_name, reg);
 	      else
-		fprintf (file, "1:\tmovabsq\t$%s, %%r10\n\tcall\t*%%r10\n",
-			 mcount_name);
+		fprintf (file, "1:\tmovabsq\t$%s, %%%s\n\tcall\t*%%%s\n",
+			 mcount_name, reg, reg);
 	      break;
 	    case CM_LARGE_PIC:
 #ifdef NO_PROFILE_COUNTERS
+	      scratch = x86_64_select_profile_regnum (false);
+	      reg = hi_reg_name[scratch];
+	      if (LEGACY_INT_REGNO_P (scratch))
+		{
+		  legacy_reg[0] = 'r';
+		  legacy_reg[1] = reg[0];
+		  legacy_reg[2] = reg[1];
+		  reg = legacy_reg;
+		}
 	      if (ASSEMBLER_DIALECT == ASM_INTEL)
 		{
 		  fprintf (file, "1:movabs\tr11, "
 				 "OFFSET FLAT:_GLOBAL_OFFSET_TABLE_-1b\n");
-		  fprintf (file, "\tlea\tr10, 1b[rip]\n");
-		  fprintf (file, "\tadd\tr10, r11\n");
+		  fprintf (file, "\tlea\t%s, 1b[rip]\n", reg);
+		  fprintf (file, "\tadd\t%s, r11\n", reg);
 		  fprintf (file, "\tmovabs\tr11, OFFSET FLAT:%s@PLTOFF\n",
 			   mcount_name);
-		  fprintf (file, "\tadd\tr10, r11\n");
-		  fprintf (file, "\tcall\tr10\n");
+		  fprintf (file, "\tadd\t%s, r11\n", reg);
+		  fprintf (file, "\tcall\t%s\n", reg);
 		  break;
 		}
 	      fprintf (file,
 		       "1:\tmovabsq\t$_GLOBAL_OFFSET_TABLE_-1b, %%r11\n");
-	      fprintf (file, "\tleaq\t1b(%%rip), %%r10\n");
-	      fprintf (file, "\taddq\t%%r11, %%r10\n");
+	      fprintf (file, "\tleaq\t1b(%%rip), %%%s\n", reg);
+	      fprintf (file, "\taddq\t%%r11, %%%s\n", reg);
 	      fprintf (file, "\tmovabsq\t$%s@PLTOFF, %%r11\n", mcount_name);
-	      fprintf (file, "\taddq\t%%r11, %%r10\n");
-	      fprintf (file, "\tcall\t*%%r10\n");
+	      fprintf (file, "\taddq\t%%r11, %%%s\n", reg);
+	      fprintf (file, "\tcall\t*%%%s\n", reg);
 #else
 	      sorry ("profiling %<-mcmodel=large%> with PIC is not supported");
 #endif

gcc/testsuite/gcc.target/i386/pr113689-1.c

@@ -0,0 +1,49 @@
+/* { dg-do run { target { lp64 && fpic } } } */
+/* { dg-options "-O2 -fno-pic -fprofile -mcmodel=large" } */
+
+#include <stdarg.h>
+
+__attribute__((noipa))
+void
+bar (int a1, int a2, int a3, int a4, int a5, int a6,
+     char *x, char *y, int *z)
+{
+  if (a1 != 1)
+    __builtin_abort ();
+  if (a2 != 2)
+    __builtin_abort ();
+  if (a3 != 3)
+    __builtin_abort ();
+  if (a4 != 4)
+    __builtin_abort ();
+  if (a5 != 5)
+    __builtin_abort ();
+  if (a6 != 6)
+    __builtin_abort ();
+  x[0] = 42;
+  y[0] = 42;
+  if (z[0] != 16)
+    __builtin_abort ();
+}
+
+__attribute__((noipa))
+void 
+foo (int c, int d, int e, int f, int g, int h, int z, ...)
+{
+  typedef char B[32];
+  B b __attribute__((aligned (32)));
+  va_list ap;
+  va_start (ap, z);
+  double x = va_arg (ap, double);
+  if (x > 40.0)
+    __builtin_abort ();
+  bar (c, d, e, f, g, h, &b[0], __builtin_alloca (z), &z);
+  va_end (ap);
+}
+
+int
+main ()
+{
+  foo (1, 2, 3, 4, 5, 6, 16, 38.0);
+  return 0;
+}

gcc/testsuite/gcc.target/i386/pr113689-2.c

@@ -0,0 +1,41 @@
+/* { dg-do run { target { lp64 && fpic } } } */
+/* { dg-options "-O2 -fpic -fprofile -mcmodel=large" } */
+
+__attribute__((noipa))
+void
+bar (int a1, int a2, int a3, int a4, int a5, int a6,
+     char *x, char *y, int *z)
+{
+  if (a1 != 1)
+    __builtin_abort ();
+  if (a2 != 2)
+    __builtin_abort ();
+  if (a3 != 3)
+    __builtin_abort ();
+  if (a4 != 4)
+    __builtin_abort ();
+  if (a5 != 5)
+    __builtin_abort ();
+  if (a6 != 6)
+    __builtin_abort ();
+  x[0] = 42;
+  y[0] = 42;
+  if (z[0] != 16)
+    __builtin_abort ();
+}
+
+__attribute__((noipa))
+void 
+foo (int c, int d, int e, int f, int g, int h, int z)
+{
+  typedef char B[32];
+  B b __attribute__((aligned (32)));
+  bar (c, d, e, f, g, h, &b[0], __builtin_alloca (z), &z);
+}
+
+int
+main ()
+{
+  foo (1, 2, 3, 4, 5, 6, 16);
+  return 0;
+}

gcc/testsuite/gcc.target/i386/pr113689-3.c

@@ -0,0 +1,48 @@
+/* { dg-do run { target { lp64 && fpic } } } */
+/* { dg-options "-O2 -fpic -fprofile -mcmodel=large" } */
+
+#include <stdarg.h>
+
+__attribute__((noipa))
+void
+bar (char *x, char *y, int *z)
+{
+  x[0] = 42;
+  y[0] = 42;
+  if (z[0] != 16)
+    __builtin_abort ();
+}
+
+__attribute__((noipa))
+void 
+foo (int a1, int a2, int a3, int a4, int a5, int a6, int z, ...)
+{
+  typedef char B[32];
+  B b __attribute__((aligned (32)));
+  va_list ap;
+  va_start (ap, z);
+  double x = va_arg (ap, double);
+  if (x > 40.0)
+    __builtin_abort ();
+  if (a1 != 1)
+    __builtin_abort ();
+  if (a2 != 2)
+    __builtin_abort ();
+  if (a3 != 3)
+    __builtin_abort ();
+  if (a4 != 4)
+    __builtin_abort ();
+  if (a5 != 5)
+    __builtin_abort ();
+  if (a6 != 6)
+    __builtin_abort ();
+  bar (&b[0], __builtin_alloca (z), &z);
+  va_end (ap);
+}
+
+int
+main ()
+{
+  foo (1, 2, 3, 4, 5, 6, 16, 38.0);
+  return 0;
+}