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* [PATCH v5] x86-64: Find a scratch register for large model profiling
@ 2024-02-02 22:47 H.J. Lu
  2024-02-05 10:56 ` Uros Bizjak
  0 siblings, 1 reply; 3+ messages in thread
From: H.J. Lu @ 2024-02-02 22:47 UTC (permalink / raw)
  To: gcc-patches; +Cc: rep.dot.nop, jakub, ubizjak

Changes in v5:

1. Add pr113689-3.c.
2. Use %r10 if ix86_profile_before_prologue () return true.
3. Try a callee-saved register which has been saved on stack in the
prologue.

Changes in v4:

1. Remove pr113689-3.c.
2. Use df_get_live_out.

Changes in v3:

1. Remove r10_ok.

Changes in v2:

1. Add int_parameter_registers to machine_function to track integer
registers used for parameter passing.
2. Update x86_64_select_profile_regnum to try %r10 first and use an
caller-saved register, which isn't used for parameter passing.

---
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 (set_saved_int_registers_bit): New.
	(test_saved_int_registers_bit): Likewise.
	(ix86_emit_save_regs): Call set_saved_int_registers_bit on
	saved register.
	(ix86_emit_save_regs_using_mov): Likewise.
	(x86_64_select_profile_regnum): New.
	(x86_function_profiler): Call x86_64_select_profile_regnum to
	get a scratch register for large model profiling.
	* config/i386/i386.h (machine_function): Add
	saved_int_registers.

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.
---
 gcc/config/i386/i386.cc                    | 119 ++++++++++++++++++---
 gcc/config/i386/i386.h                     |   5 +
 gcc/testsuite/gcc.target/i386/pr113689-1.c |  49 +++++++++
 gcc/testsuite/gcc.target/i386/pr113689-2.c |  41 +++++++
 gcc/testsuite/gcc.target/i386/pr113689-3.c |  48 +++++++++
 5 files changed, 247 insertions(+), 15 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr113689-1.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr113689-2.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr113689-3.c

diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index b3e7c74846e..1c7aaa4535e 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -7387,6 +7387,32 @@ choose_baseaddr (HOST_WIDE_INT cfa_offset, unsigned int *align,
   return plus_constant (Pmode, base_reg, base_offset);
 }
 
+/* Set the integer register REGNO bit in saved_int_registers.  */
+
+static void
+set_saved_int_registers_bit (int regno)
+{
+  if (LEGACY_INT_REGNO_P (regno))
+    cfun->machine->saved_int_registers |= 1 << regno;
+  else
+    cfun->machine->saved_int_registers
+      |= 1 << (regno - FIRST_REX_INT_REG + 8);
+}
+
+/* Return true if the integer register REGNO bit in saved_int_registers
+   is set.  */
+
+static bool
+test_saved_int_registers_bit (int regno)
+{
+  if (LEGACY_INT_REGNO_P (regno))
+    return (cfun->machine->saved_int_registers
+	    & (1 << regno)) != 0;
+  else
+    return (cfun->machine->saved_int_registers
+	    & (1 << (regno - FIRST_REX_INT_REG + 8))) != 0;
+}
+
 /* Emit code to save registers in the prologue.  */
 
 static void
@@ -7403,6 +7429,7 @@ ix86_emit_save_regs (void)
 	    insn = emit_insn (gen_push (gen_rtx_REG (word_mode, regno),
 					TARGET_APX_PPX));
 	    RTX_FRAME_RELATED_P (insn) = 1;
+	    set_saved_int_registers_bit (regno);
 	  }
     }
   else
@@ -7415,6 +7442,7 @@ ix86_emit_save_regs (void)
       for (regno = FIRST_PSEUDO_REGISTER - 1; regno >= 0; regno--)
 	if (GENERAL_REGNO_P (regno) && ix86_save_reg (regno, true, true))
 	  {
+	    set_saved_int_registers_bit (regno);
 	    if (aligned)
 	      {
 		regno_list[loaded_regnum++] = regno;
@@ -7567,6 +7595,7 @@ ix86_emit_save_regs_using_mov (HOST_WIDE_INT cfa_offset)
       {
         ix86_emit_save_reg_using_mov (word_mode, regno, cfa_offset);
 	cfa_offset -= UNITS_PER_WORD;
+	set_saved_int_registers_bit (regno);
       }
 }
 
@@ -22749,6 +22778,48 @@ 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
+	&& (!REX2_INT_REGNO_P (i) || TARGET_APX_EGPR)
+	&& !fixed_regs[i]
+	&& (test_saved_int_registers_bit (i)
+	    || (call_used_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 +22854,60 @@ 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_prefix;
+      const char *reg;
+
       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];
+	      reg_prefix = LEGACY_INT_REGNO_P (scratch) ? "r" : "";
 	      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%s, OFFSET FLAT:%s\n"
+			 "\tcall\t%s%s\n",
+			 reg_prefix, reg, mcount_name, reg_prefix, reg);
 	      else
-		fprintf (file, "1:\tmovabsq\t$%s, %%r10\n\tcall\t*%%r10\n",
-			 mcount_name);
+		fprintf (file,
+			 "1:\tmovabsq\t$%s, %%%s%s\n\tcall\t*%%%s%s\n",
+			 mcount_name, reg_prefix, reg, reg_prefix, reg);
 	      break;
 	    case CM_LARGE_PIC:
 #ifdef NO_PROFILE_COUNTERS
+	      scratch = x86_64_select_profile_regnum (false);
+	      reg = hi_reg_name[scratch];
+	      reg_prefix = LEGACY_INT_REGNO_P (scratch) ? "r" : "";
 	      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%s, 1b[rip]\n",
+			   reg_prefix, reg);
+		  fprintf (file, "\tadd\t%s%s, r11\n",
+			   reg_prefix, 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%s, r11\n",
+			   reg_prefix, reg);
+		  fprintf (file, "\tcall\t%s%s\n",
+			   reg_prefix, reg);
 		  break;
 		}
 	      fprintf (file,
 		       "1:\tmovabsq\t$_GLOBAL_OFFSET_TABLE_-1b, %%r11\n");
-	      fprintf (file, "\tleaq\t1b(%%rip), %%r10\n");
-	      fprintf (file, "\taddq\t%%r11, %%r10\n");
+	      fprintf (file, "\tleaq\t1b(%%rip), %%%s%s\n",
+		       reg_prefix, reg);
+	      fprintf (file, "\taddq\t%%r11, %%%s%s\n",
+		       reg_prefix, reg);
 	      fprintf (file, "\tmovabsq\t$%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%s\n",
+		       reg_prefix, reg);
+	      fprintf (file, "\tcall\t*%%%s%s\n",
+		       reg_prefix, reg);
 #else
 	      sorry ("profiling %<-mcmodel=large%> with PIC is not supported");
 #endif
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 35ce8b00d36..33821a04074 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -2847,6 +2847,11 @@ struct GTY(()) machine_function {
   /* True if red zone is used.  */
   BOOL_BITFIELD red_zone_used : 1;
 
+  /* Bit mask for integer registers saved on stack in prologue.  The
+     lower 8 bits are for legacy registers and the upper 8 bits are
+     for r8-r15.  */
+  unsigned int saved_int_registers : 16;
+
   /* The largest alignment, in bytes, of stack slot actually used.  */
   unsigned int max_used_stack_alignment;
 
diff --git a/gcc/testsuite/gcc.target/i386/pr113689-1.c b/gcc/testsuite/gcc.target/i386/pr113689-1.c
new file mode 100644
index 00000000000..8285c0a07b7
--- /dev/null
+++ b/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;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr113689-2.c b/gcc/testsuite/gcc.target/i386/pr113689-2.c
new file mode 100644
index 00000000000..2e5579ac546
--- /dev/null
+++ b/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;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr113689-3.c b/gcc/testsuite/gcc.target/i386/pr113689-3.c
new file mode 100644
index 00000000000..dab75190635
--- /dev/null
+++ b/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;
+}
-- 
2.43.0


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2024-02-02 22:47 [PATCH v5] x86-64: Find a scratch register for large model profiling H.J. Lu
2024-02-05 10:56 ` Uros Bizjak
2024-02-05 16:44   ` H.J. Lu

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