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Re: [PATCH, i386] Optionally use %xmm0 to return float and/or doublevalues (take 3)


Here is my patch with the times for a povray benchmark run.

SSE-related compiler options:
  -msse -msse2 -mfpmath=sse -march=pentium4 -mtune=pentium4

With the patch:
  Total Scene Processing Times
    Parse Time:    0 hours  0 minutes  1 seconds (1 seconds)
    Photon Time:   0 hours  0 minutes 38 seconds (38 seconds)
    Render Time:   0 hours 31 minutes 46 seconds (1906 seconds)
    Total Time:    0 hours 32 minutes 25 seconds (1945 seconds)

Without the patch:
  Total Scene Processing Times
    Parse Time:    0 hours  0 minutes  1 seconds (1 seconds)
    Photon Time:   0 hours  0 minutes 38 seconds (38 seconds)
    Render Time:   0 hours 32 minutes  4 seconds (1924 seconds)
    Total Time:    0 hours 32 minutes 43 seconds (1963 seconds)

So povray is 1% faster with the patch.

Paolo
gcc:
2005-01-25  Paolo Bonzini  <bonzini@gnu.org>

	* config/i386/i386-protos.h (ix86_function_value): Accept two
	arguments, like the target macro.
	* config/i386/i386.h (FUNCTION_VALUE): Pass both arguments.
	* config/i386/i386.c (ix86_function_value): Accept the second
	argument of the target macro.
	(ix86_function_ok_for_sibcall): Pass a function pointer to
	ix86_function_value.
	(ix86_function_value, ix86_libcall_value) [!TARGET_64BIT]: Adjust
	call to ix86_value_regno).
	(ix86_value_regno): Add support for returning floating point values
	in SSE registers.

gcc/testsuite:
2005-01-25  Paolo Bonzini  <bonzini@gnu.org>

	* gcc.dg/i386-ssefn-1.c, gcc.dg/i386-ssefn-2.c, gcc.dg/i386-ssefn-3.c,
	gcc.dg/i386-ssefn-4.c: New.

Index: i386-protos.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/i386/i386-protos.h,v
retrieving revision 1.128
diff -u -p -r1.128 i386-protos.h
--- i386-protos.h	20 Jan 2005 18:20:42 -0000	1.128
+++ i386-protos.h	26 Jan 2005 14:48:16 -0000
@@ -199,7 +199,7 @@ extern void init_cumulative_args (CUMULA
 extern rtx function_arg (CUMULATIVE_ARGS *, enum machine_mode, tree, int);
 extern void function_arg_advance (CUMULATIVE_ARGS *, enum machine_mode,
 				  tree, int);
-extern rtx ix86_function_value (tree);
+extern rtx ix86_function_value (tree, tree);
 #endif
 
 #endif
Index: i386.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/i386/i386.c,v
retrieving revision 1.790
diff -u -p -r1.790 i386.c
--- i386.c	25 Jan 2005 18:43:55 -0000	1.790
+++ i386.c	26 Jan 2005 14:48:19 -0000
@@ -913,7 +913,7 @@ const struct attribute_spec ix86_attribu
 static bool ix86_function_ok_for_sibcall (tree, tree);
 static tree ix86_handle_cdecl_attribute (tree *, tree, tree, int, bool *);
 static tree ix86_handle_regparm_attribute (tree *, tree, tree, int, bool *);
-static int ix86_value_regno (enum machine_mode);
+static int ix86_value_regno (enum machine_mode, tree);
 static bool contains_128bit_aligned_vector_p (tree);
 static rtx ix86_struct_value_rtx (tree, int);
 static bool ix86_ms_bitfield_layout_p (tree);
@@ -1643,19 +1643,27 @@ const struct attribute_spec ix86_attribu
 static bool
 ix86_function_ok_for_sibcall (tree decl, tree exp)
 {
+  tree func;
+
   /* If we are generating position-independent code, we cannot sibcall
      optimize any indirect call, or a direct call to a global function,
      as the PLT requires %ebx be live.  */
   if (!TARGET_64BIT && flag_pic && (!decl || TREE_PUBLIC (decl)))
     return false;
 
+  if (decl)
+    func = decl;
+  else
+    func = NULL;
+
   /* If we are returning floats on the 80387 register stack, we cannot
      make a sibcall from a function that doesn't return a float to a
      function that does or, conversely, from a function that does return
      a float to a function that doesn't; the necessary stack adjustment
      would not be executed.  */
-  if (STACK_REG_P (ix86_function_value (TREE_TYPE (exp)))
-      != STACK_REG_P (ix86_function_value (TREE_TYPE (DECL_RESULT (cfun->decl)))))
+  if (STACK_REG_P (ix86_function_value (TREE_TYPE (exp), func))
+      != STACK_REG_P (ix86_function_value (TREE_TYPE (DECL_RESULT (cfun->decl)),
+					   cfun->decl)))
     return false;
 
   /* If this call is indirect, we'll need to be able to use a call-clobbered
@@ -3031,7 +3039,7 @@ ix86_function_value_regno_p (int regno)
    If the precise function being called is known, FUNC is its FUNCTION_DECL;
    otherwise, FUNC is 0.  */
 rtx
-ix86_function_value (tree valtype)
+ix86_function_value (tree valtype, tree func)
 {
   enum machine_mode natmode = type_natural_mode (valtype);
 
@@ -3047,7 +3055,7 @@ ix86_function_value (tree valtype)
       return ret;
     }
   else
-    return gen_rtx_REG (TYPE_MODE (valtype), ix86_value_regno (natmode));
+    return gen_rtx_REG (TYPE_MODE (valtype), ix86_value_regno (natmode, func));
 }
 
 /* Return false iff type is returned in memory.  */
@@ -3149,23 +3157,35 @@ ix86_libcall_value (enum machine_mode mo
 	}
     }
   else
-    return gen_rtx_REG (mode, ix86_value_regno (mode));
+    return gen_rtx_REG (mode, ix86_value_regno (mode, NULL));
 }
 
 /* Given a mode, return the register to use for a return value.  */
 
 static int
-ix86_value_regno (enum machine_mode mode)
+ix86_value_regno (enum machine_mode mode, tree func)
 {
-  /* Floating point return values in %st(0).  */
-  if (GET_MODE_CLASS (mode) == MODE_FLOAT && TARGET_FLOAT_RETURNS_IN_80387)
-    return FIRST_FLOAT_REG;
+  gcc_assert (!TARGET_64BIT);
+
   /* 16-byte vector modes in %xmm0.  See ix86_return_in_memory for where
      we prevent this case when sse is not available.  */
   if (mode == TImode || (VECTOR_MODE_P (mode) && GET_MODE_SIZE (mode) == 16))
     return FIRST_SSE_REG;
-  /* Everything else in %eax.  */
-  return 0;
+
+  /* Most things go in %eax, except (unless -mno-fp-ret-in-387) fp values.  */
+  if (GET_MODE_CLASS (mode) != MODE_FLOAT || !TARGET_FLOAT_RETURNS_IN_80387)
+    return 0;
+
+  /* Floating point return values in %st(0), except for local functions when
+     SSE math is enabled.  */
+  if (func && SSE_FLOAT_MODE_P (mode) && TARGET_SSE_MATH)
+    {
+      struct cgraph_local_info *i = cgraph_local_info (func);
+      if (k && i && i->local)
+        return FIRST_SSE_REG;
+    }
+
+  return FIRST_FLOAT_REG;
 }
 
 /* Create the va_list data type.  */
Index: i386.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/i386/i386.h,v
retrieving revision 1.419
diff -u -p -r1.419 i386.h
--- i386.h	20 Jan 2005 06:47:25 -0000	1.419
+++ i386.h	26 Jan 2005 14:48:19 -0000
@@ -1705,7 +1705,7 @@ enum reg_class
    If the precise function being called is known, FUNC is its FUNCTION_DECL;
    otherwise, FUNC is 0.  */
 #define FUNCTION_VALUE(VALTYPE, FUNC)  \
-   ix86_function_value (VALTYPE)
+   ix86_function_value (VALTYPE, FUNC)
 
 #define FUNCTION_VALUE_REGNO_P(N) \
   ix86_function_value_regno_p (N)
Index: testsuite/gcc.dg/i386-ssefn-1.c
===================================================================
RCS file: testsuite/gcc.dg/i386-ssefn-1.c
diff -N testsuite/gcc.dg/i386-ssefn-1.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gcc.dg/i386-ssefn-1.c	26 Jan 2005 14:48:52 -0000
@@ -0,0 +1,30 @@
+/* Test argument passing with SSE and local functions
+   Written by Paolo Bonzini, 25 January 2005 */
+
+/* { dg-do compile { target i?86-*-* } } */
+/* { dg-final { scan-assembler "movss" } } */
+/* { dg-final { scan-assembler "mulss" } } */
+/* { dg-final { scan-assembler-not "movsd" } } */
+/* { dg-final { scan-assembler-not "mulsd" } } */
+/* { dg-options "-O2 -msse -mfpmath=sse -fno-inline" } */
+
+static float xs (void)
+{
+  return 3.14159265;
+}
+
+float ys (float a)
+{
+  return xs () * a;
+}
+
+static double xd (void)
+{
+  return 3.1415926535;
+}
+
+double yd (double a)
+{
+  return xd () * a;
+}
+
Index: testsuite/gcc.dg/i386-ssefn-2.c
===================================================================
RCS file: testsuite/gcc.dg/i386-ssefn-2.c
diff -N testsuite/gcc.dg/i386-ssefn-2.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gcc.dg/i386-ssefn-2.c	26 Jan 2005 14:48:52 -0000
@@ -0,0 +1,30 @@
+/* Test argument passing with SSE2 and local functions
+   Written by Paolo Bonzini, 25 January 2005 */
+
+/* { dg-do compile { target i?86-*-* } } */
+/* { dg-final { scan-assembler "movss" } } */
+/* { dg-final { scan-assembler "mulss" } } */
+/* { dg-final { scan-assembler "movsd" } } */
+/* { dg-final { scan-assembler "mulsd" } } */
+/* { dg-options "-O2 -msse2 -mfpmath=sse -fno-inline" } */
+
+static float xs (void)
+{
+  return 3.14159265;
+}
+
+float ys (float a)
+{
+  return xs () * a;
+}
+
+static double xd (void)
+{
+  return 3.1415926535;
+}
+
+double yd (double a)
+{
+  return xd () * a;
+}
+
Index: testsuite/gcc.dg/i386-ssefn-3.c
===================================================================
RCS file: testsuite/gcc.dg/i386-ssefn-3.c
diff -N testsuite/gcc.dg/i386-ssefn-3.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gcc.dg/i386-ssefn-3.c	26 Jan 2005 14:48:52 -0000
@@ -0,0 +1,42 @@
+/* Execution test for argument passing with SSE and local functions
+   Written by Paolo Bonzini, 25 January 2005 */
+
+/* { dg-do run { target i?86-*-* } } */
+/* { dg-options "-O2 -msse -mfpmath=sse" } */
+#include <assert.h>
+#include "i386-cpuid.h"
+
+static float xs (void)
+{
+  return 3.14159265;
+}
+
+float ys (float a)
+{
+  return xs () * a;
+}
+
+static double xd (void)
+{
+  return 3.1415926535;
+}
+
+double yd (double a)
+{
+  return xd () * a;
+}
+
+int main()
+{
+  unsigned long cpu_facilities;
+
+  cpu_facilities = i386_cpuid ();
+
+  if (cpu_facilities & bit_SSE)
+    {
+      assert (ys (1) == xs ());
+      assert (ys (2) == xs () * 2);
+      assert (yd (1) == xd ());
+      assert (yd (2) == xd () * 2);
+    }
+}
Index: testsuite/gcc.dg/i386-ssefn-4.c
===================================================================
RCS file: testsuite/gcc.dg/i386-ssefn-4.c
diff -N testsuite/gcc.dg/i386-ssefn-4.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gcc.dg/i386-ssefn-4.c	26 Jan 2005 14:48:52 -0000
@@ -0,0 +1,42 @@
+/* Execution test for argument passing with SSE2 and local functions
+   Written by Paolo Bonzini, 25 January 2005 */
+
+/* { dg-do run { target i?86-*-* } } */
+/* { dg-options "-O2 -msse2 -mfpmath=sse" } */
+#include <assert.h>
+#include "i386-cpuid.h"
+
+static float xs (void)
+{
+  return 3.14159265;
+}
+
+float ys (float a)
+{
+  return xs () * a;
+}
+
+static double xd (void)
+{
+  return 3.1415926535;
+}
+
+double yd (double a)
+{
+  return xd () * a;
+}
+
+int main()
+{
+  unsigned long cpu_facilities;
+
+  cpu_facilities = i386_cpuid ();
+
+  if (cpu_facilities & bit_SSE2)
+    {
+      assert (ys (1) == xs ());
+      assert (ys (2) == xs () * 2);
+      assert (yd (1) == xd ());
+      assert (yd (2) == xd () * 2);
+    }
+}

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