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[PATCH]: add folding of builtin modf

From: "Kaveh R. GHAZI" <ghazi at caip dot rutgers dot edu>
To: gcc-patches at gcc dot gnu dot org
Date: Sat, 24 Feb 2007 10:37:30 -0500 (EST)
Subject: [PATCH]: add folding of builtin modf
This patch adds folding of builtin modf when the first argument is a
constant.

Tested on sparc-sun-solaris2.10, no regressions.

Okay for mainline?

		Thanks,
		--Kaveh


2007-02-24  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>

	* builtins.c (fold_builtin_modf): New.
	(fold_builtin_2): Use it.

testsuite:
	* gcc.dg/torture/builtin-modf-1.c: New test.

diff -rup orig/egcc-SVN20070223/gcc/builtins.c egcc-SVN20070223/gcc/builtins.c
--- orig/egcc-SVN20070223/gcc/builtins.c	2007-02-23 09:49:47.000000000 -0500
+++ egcc-SVN20070223/gcc/builtins.c	2007-02-24 00:40:02.563843168 -0500
@@ -9214,6 +9214,62 @@ fold_builtin_load_exponent (tree arg0, t
   return NULL_TREE;
 }

+/* Fold a call to builtin modf.  */
+
+static tree
+fold_builtin_modf (tree arg0, tree arg1, tree rettype)
+{
+  if (! validate_arg (arg0, REAL_TYPE) || ! validate_arg (arg1, POINTER_TYPE))
+    return NULL_TREE;
+
+  STRIP_NOPS (arg0);
+
+  if (!(TREE_CODE (arg0) == REAL_CST && ! TREE_OVERFLOW (arg0)))
+    return NULL_TREE;
+
+  arg1 = build_fold_indirect_ref (arg1);
+
+  /* Proceed if a valid pointer type was passed in.  */
+  if (TYPE_MAIN_VARIANT (TREE_TYPE (arg1)) == TYPE_MAIN_VARIANT (rettype))
+    {
+      const REAL_VALUE_TYPE *const value = TREE_REAL_CST_PTR (arg0);
+      REAL_VALUE_TYPE trunc, frac;
+
+      switch (value->cl)
+      {
+      case rvc_nan:
+      case rvc_zero:
+	/* For +-NaN or +-0, return (*arg1 = arg0, arg0).  */
+	trunc = frac = *value;
+	break;
+      case rvc_inf:
+	/* For +-Inf, return (*arg1 = arg0, +-0).  */
+	frac = dconst0;
+	frac.sign = value->sign;
+	trunc = *value;
+	break;
+      case rvc_normal:
+	/* Return (*arg1 = trunc(arg0), arg0-trunc(arg0)).  */
+	real_trunc (&trunc, VOIDmode, value);
+	real_arithmetic (&frac, MINUS_EXPR, value, &trunc);
+	/* If the original number was negative and already
+	   integral, then the fractional part is -0.0.  */
+	if (value->sign && frac.cl == rvc_zero)
+	  frac.sign = value->sign;
+	break;
+      }
+
+      /* Create the COMPOUND_EXPR (*arg1 = trunc, frac). */
+      arg1 = fold_build2 (MODIFY_EXPR, rettype, arg1,
+			  build_real (rettype, trunc));
+      TREE_SIDE_EFFECTS (arg1) = 1;
+      return fold_build2 (COMPOUND_EXPR, rettype, arg1,
+			  build_real (rettype, frac));
+    }
+
+  return NULL_TREE;
+}
+
 /* Fold a call to __builtin_isnan(), __builtin_isinf, __builtin_finite.
    ARG is the argument for the call.  */

@@ -9690,6 +9746,9 @@ fold_builtin_2 (tree fndecl, tree arg0,
     CASE_FLT_FN (BUILT_IN_FREXP):
       return fold_builtin_frexp (arg0, arg1, type);

+    CASE_FLT_FN (BUILT_IN_MODF):
+      return fold_builtin_modf (arg0, arg1, type);
+
     case BUILT_IN_BZERO:
       return fold_builtin_bzero (arg0, arg1, ignore);

diff -rup orig/egcc-SVN20070223/gcc/testsuite/gcc.dg/torture/builtin-modf-1.c egcc-SVN20070223/gcc/testsuite/gcc.dg/torture/builtin-modf-1.c
--- orig/egcc-SVN20070223/gcc/testsuite/gcc.dg/torture/builtin-modf-1.c	2007-02-23 11:30:15.106672005 -0500
+++ egcc-SVN20070223/gcc/testsuite/gcc.dg/torture/builtin-modf-1.c	2007-02-24 01:08:14.114118356 -0500
@@ -0,0 +1,159 @@
+/* Copyright (C) 2007  Free Software Foundation.
+
+   Verify that built-in folding of modf is correctly performed by the
+   compiler.
+
+   Origin: Kaveh R. Ghazi,  February 23, 2007.  */
+
+/* { dg-do link } */
+
+extern void link_error(int);
+
+/* Return TRUE if the sign of X != sign of Y.  This is important when
+   comparing signed zeros.  */
+#define CKSGN_F(X,Y) \
+  (__builtin_copysignf(1.0F,(X)) != __builtin_copysignf(1.0F,(Y)))
+#define CKSGN(X,Y) \
+  (__builtin_copysign(1.0,(X)) != __builtin_copysign(1.0,(Y)))
+#define CKSGN_L(X,Y) \
+  (__builtin_copysignl(1.0L,(X)) != __builtin_copysignl(1.0L,(Y)))
+
+/* We use these macros if we can only check these when optimizing.  In
+   some cases we rely on other optimizations to propagate the value
+   and fold away certain constructs.  Likewise for the sign testing.
+   TRUE means an error occurred.  */
+#ifdef __OPTIMIZE__
+#define CKRES(X) (X)
+#define CKIPTR(X,Y) X != Y
+#define CKSGN_IPTR_F(X,Y) CKSGN_F(X,Y)
+#define CKSGN_IPTR(X,Y) CKSGN(X,Y)
+#define CKSGN_IPTR_L(X,Y) CKSGN_L(X,Y)
+#else
+#define CKRES(X) 0
+#define CKIPTR(X,Y) 0
+#define CKSGN_IPTR_F(X,Y) 0
+#define CKSGN_IPTR(X,Y) 0
+#define CKSGN_IPTR_L(X,Y) 0
+#endif
+
+/* Test that modf(ARG1,&iptr) == FRACRES && iptr == INTRES.  Check the
+   sign in case we get -0.0.  */
+#define TESTIT_MODF(ARG,INTRES,FRACRES) do { \
+  float iptrf = 0.5; double iptr = 0.5; long double iptrl = 0.5; \
+  if (__builtin_modff(ARG##f,&iptrf) != FRACRES##f \
+      || CKIPTR(iptrf,INTRES##f) \
+      || CKSGN_F(__builtin_modff(ARG##f,&iptrf),FRACRES##f) \
+      || CKSGN_IPTR_F(iptrf,INTRES##f)) \
+    link_error(__LINE__); \
+  if (__builtin_modf(ARG,&iptr) != FRACRES \
+      || CKIPTR(iptr,INTRES) \
+      || CKSGN(__builtin_modf(ARG,&iptr),FRACRES) \
+      || CKSGN_IPTR(iptr,INTRES)) \
+    link_error(__LINE__); \
+  if (__builtin_modfl(ARG##l,&iptrl) != FRACRES##l \
+      || CKIPTR(iptrl,INTRES##l) \
+      || CKSGN_L(__builtin_modfl(ARG##l,&iptrl),FRACRES##l) \
+      || CKSGN_IPTR_L(iptrl,INTRES##l)) \
+    link_error(__LINE__); \
+  } while (0)
+
+/* Test that modf(NEG FUNCARG(ARGARG, &iptr)) == FRACRES &&
+   FUNCRES(iptr) is true.  Check the sign of both as well.  This is
+   for checking an argument of Inf.  */
+#define TESTIT_MODF2(NEG,FUNCARG,ARGARG,FUNCRES,FRACRES) do { \
+  float iptrf = 0.5; double iptr = 0.5; long double iptrl = 0.5; \
+  if (__builtin_modff(NEG __builtin_##FUNCARG##f(ARGARG),&iptrf) != FRACRES##f \
+      || CKSGN_F(__builtin_modff(NEG __builtin_##FUNCARG##f(ARGARG),&iptrf), FRACRES##f) \
+      || CKIPTR(!__builtin_##FUNCRES##f(iptrf),0) \
+      || CKSGN_IPTR_F(iptrf,FRACRES##f)) \
+    link_error(__LINE__); \
+  if (__builtin_modf(NEG __builtin_##FUNCARG(ARGARG),&iptr) != FRACRES \
+      || CKSGN(__builtin_modf(NEG __builtin_##FUNCARG(ARGARG),&iptr), FRACRES) \
+      || CKIPTR(!__builtin_##FUNCRES(iptr),0) \
+      || CKSGN_IPTR(iptr,FRACRES)) \
+    link_error(__LINE__); \
+  if (__builtin_modfl(NEG __builtin_##FUNCARG##l(ARGARG),&iptrl) != FRACRES##l \
+      || CKSGN_L(__builtin_modfl(NEG __builtin_##FUNCARG##l(ARGARG),&iptrl), FRACRES##l) \
+      || CKIPTR(!__builtin_##FUNCRES##l(iptrl),0) \
+      || CKSGN_IPTR_L(iptrl,FRACRES##l)) \
+    link_error(__LINE__); \
+  } while (0)
+
+/* Test that FUNCRES(modf(NEG FUNCARG(ARGARG, &iptr))) is true &&
+   FUNCRES(iptr) is true.  Check the sign of both as well.  This is
+   for checking an argument of NaN.  */
+#define TESTIT_MODF3(NEG,FUNCARG,ARGARG,FUNCRES) do { \
+  float iptrf = 0.5; double iptr = 0.5; long double iptrl = 0.5; \
+  if (CKRES(!__builtin_##FUNCRES##f(__builtin_modff(NEG __builtin_##FUNCARG##f(ARGARG),&iptrf))) \
+      || CKSGN_F(__builtin_modff(NEG __builtin_##FUNCARG##f(ARGARG),&iptrf), NEG 1) \
+      || CKIPTR(!__builtin_##FUNCRES##f(iptrf),0) \
+      || CKSGN_IPTR_F(iptrf,NEG 1)) \
+    link_error(__LINE__); \
+  if (CKRES(!__builtin_##FUNCRES(__builtin_modf(NEG __builtin_##FUNCARG(ARGARG),&iptr))) \
+      || CKSGN(__builtin_modf(NEG __builtin_##FUNCARG(ARGARG),&iptr), NEG 1) \
+      || CKIPTR(!__builtin_##FUNCRES(iptr),0) \
+      || CKSGN_IPTR(iptr,NEG 1)) \
+    link_error(__LINE__); \
+  if (CKRES(!__builtin_##FUNCRES##l(__builtin_modfl(NEG __builtin_##FUNCARG##l(ARGARG),&iptrl))) \
+      || CKSGN_L(__builtin_modfl(NEG __builtin_##FUNCARG##l(ARGARG),&iptrl), NEG 1) \
+      || CKIPTR(!__builtin_##FUNCRES##l(iptrl),0) \
+      || CKSGN_IPTR_L(iptrl,NEG 1)) \
+    link_error(__LINE__); \
+  } while (0)
+
+void __attribute__ ((__noinline__))
+foo(void)
+{
+  /* Test that modf(ARG1,&iptr) -> ARG3 && iptr == ARG2.  */
+  TESTIT_MODF (0x1p10F+0.5, 0x1p10, 0.5);
+  TESTIT_MODF (0x1p10F+0x1p-10, 0x1p10, 0x1p-10);
+  TESTIT_MODF (12345678L/17.0, 726216.0, -726216L+12345678L/17.0);
+  TESTIT_MODF (555.555, 555.0, -555+555.555);
+  TESTIT_MODF (5000/11.0, 454.0, -454+5000/11.0);
+  TESTIT_MODF (1000/7.0, 142.0, -142+1000/7.0);
+  TESTIT_MODF (123/7.0, 17.0, -17+123/7.0);
+  TESTIT_MODF (117/7.0, 16.0, -16+117/7.0);
+  TESTIT_MODF (5.5, 5.0, 0.5);
+  TESTIT_MODF (1.5, 1.0, 0.5);
+  TESTIT_MODF (4/3.0, 1.0, -1+4/3.0);
+  TESTIT_MODF (1.0, 1.0, 0.0);
+  TESTIT_MODF (0.5, 0.0, 0.5);
+  TESTIT_MODF (4/9.0, 0.0, 4/9.0);
+  TESTIT_MODF (1/3.0, 0.0, 1/3.0);
+  TESTIT_MODF (1/9.0, 0.0, 1/9.0);
+  TESTIT_MODF (0.0, 0.0, 0.0);
+
+  TESTIT_MODF (-0.0, -0.0, -0.0);
+  TESTIT_MODF (-1/9.0, -0.0, -1/9.0);
+  TESTIT_MODF (-1/3.0, -0.0, -1/3.0);
+  TESTIT_MODF (-4/9.0, -0.0, -4/9.0);
+  TESTIT_MODF (-0.5, -0.0, -0.5);
+  TESTIT_MODF (-1.0, -1.0, -0.0);
+  TESTIT_MODF (-4/3.0, -1.0, 1-4/3.0);
+  TESTIT_MODF (-1.5, -1.0, -0.5);
+  TESTIT_MODF (-5.5, -5.0, -0.5);
+  TESTIT_MODF (-117/7.0, -16.0, 16-117/7.0);
+  TESTIT_MODF (-123/7.0, -17.0, 17-123/7.0);
+  TESTIT_MODF (-1000/7.0, -142.0, 142-1000/7.0);
+  TESTIT_MODF (-5000/11.0, -454.0, 454-5000/11.0);
+  TESTIT_MODF (-555.555, -555.0, 555-555.555);
+  TESTIT_MODF (-12345678L/17.0, -726216.0, 726216L-12345678L/17.0);
+  TESTIT_MODF (-0x1p10F-0x1p-10, -0x1p10, -0x1p-10);
+  TESTIT_MODF (-0x1p10F-0.5, -0x1p10, -0.5);
+
+
+  /* Test for modf(+-Inf,&i) -> (i=+-0.0, +-Inf).  */
+  TESTIT_MODF2 ( ,inf, , isinf, 0.0);
+  TESTIT_MODF2 (- ,inf, , isinf, -0.0);
+
+  /* Test for and modf(+-NaN,&i) -> (i=+-NaN, +-NaN).  */
+  TESTIT_MODF3 ( ,nan, "", isnan);
+  TESTIT_MODF3 (- ,nan, "", isnan);
+}
+
+int main()
+{
+  foo();
+
+  return 0;
+}
Follow-Ups:
- Re: [PATCH]: add folding of builtin modf
  - From: Richard Guenther
- Re: [PATCH]: add folding of builtin modf
  - From: Kaz Kojima
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