Move pow folds to match.pd

Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.

gcc/
	* builtins.c (fold_builtin_pow): Delete in favor of...
	(fold_const_builtin_pow): ...this new function.  Only handle constant
	arguments.
	(fold_builtin_2): Update accordingly.
	* match.pd: Add rules previously handled by fold_builtin_pow.

gcc/testsuite/
	* gcc.dg/torture/builtin-math-1.c: Skip at -O0.

From-SVN: r229408

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 442cd85de9ce0c18cd07945fe704a541cc1ec214..f26ea3de501e7de8b4fa43f29f1683a5bc55fe92 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2015-10-27  Richard Sandiford  <richard.sandiford@arm.com>
+
+       * builtins.c (fold_builtin_pow): Delete in favor of...
+       (fold_const_builtin_pow): ...this new function.  Only handle constant
+       arguments.
+       (fold_builtin_2): Update accordingly.
+       * match.pd: Add rules previously handled by fold_builtin_pow.
+
 2015-10-27  Richard Sandiford  <richard.sandiford@arm.com>
 
        * builtins.c (fold_builtin_hypot): Delete.

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 64106a1d15028f6b549ebec88f6ee7b91c7e474f..88c0576edac6a0b9904c0d6c342d6cbf49899c66 100644 (file)
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -156,7 +156,6 @@ static tree rewrite_call_expr (location_t, tree, int, tree, int, ...);
 static bool validate_arg (const_tree, enum tree_code code);
 static rtx expand_builtin_fabs (tree, rtx, rtx);
 static rtx expand_builtin_signbit (tree, rtx);
-static tree fold_builtin_pow (location_t, tree, tree, tree, tree);
 static tree fold_builtin_powi (location_t, tree, tree, tree, tree);
 static tree fold_builtin_bitop (tree, tree);
 static tree fold_builtin_strchr (location_t, tree, tree, tree);
@@ -7478,7 +7477,7 @@ fold_builtin_bswap (tree fndecl, tree arg)
 /* Fold a builtin function call to pow, powf, or powl.  Return
    NULL_TREE if no simplification can be made.  */
 static tree
-fold_builtin_pow (location_t loc, tree fndecl, tree arg0, tree arg1, tree type)
+fold_const_builtin_pow (tree arg0, tree arg1, tree type)
 {
   tree res;
 
@@ -7490,127 +7489,28 @@ fold_builtin_pow (location_t loc, tree fndecl, tree arg0, tree arg1, tree type)
   if ((res = do_mpfr_arg2 (arg0, arg1, type, mpfr_pow)))
     return res;
 
-  /* Optimize pow(1.0,y) = 1.0.  */
-  if (real_onep (arg0))
-    return omit_one_operand_loc (loc, type, build_real (type, dconst1), arg1);
-
-  if (TREE_CODE (arg1) == REAL_CST
+  /* Check for an integer exponent.  */
+  if (TREE_CODE (arg0) == REAL_CST
+      && !TREE_OVERFLOW (arg0)
+      && TREE_CODE (arg1) == REAL_CST
       && !TREE_OVERFLOW (arg1))
     {
-      REAL_VALUE_TYPE cint;
-      REAL_VALUE_TYPE c;
-      HOST_WIDE_INT n;
-
-      c = TREE_REAL_CST (arg1);
-
-      /* Optimize pow(x,0.0) = 1.0.  */
-      if (real_equal (&c, &dconst0))
-       return omit_one_operand_loc (loc, type, build_real (type, dconst1),
-                                arg0);
-
-      /* Optimize pow(x,1.0) = x.  */
-      if (real_equal (&c, &dconst1))
-       return arg0;
-
-      /* Optimize pow(x,-1.0) = 1.0/x.  */
-      if (real_equal (&c, &dconstm1))
-       return fold_build2_loc (loc, RDIV_EXPR, type,
-                           build_real (type, dconst1), arg0);
-
-      /* Optimize pow(x,0.5) = sqrt(x).  */
-      if (flag_unsafe_math_optimizations
-         && real_equal (&c, &dconsthalf))
+      REAL_VALUE_TYPE cint1;
+      const REAL_VALUE_TYPE *c0 = TREE_REAL_CST_PTR (arg0);
+      const REAL_VALUE_TYPE *c1 = TREE_REAL_CST_PTR (arg1);
+      HOST_WIDE_INT n1 = real_to_integer (c1);
+      real_from_integer (&cint1, VOIDmode, n1, SIGNED);
+      /* Attempt to evaluate pow at compile-time, unless this should
+        raise an exception.  */
+      if (real_identical (c1, &cint1)
+         && (n1 > 0
+             || (!flag_trapping_math && !flag_errno_math)
+             || !real_equal (c0, &dconst0)))
        {
-         tree sqrtfn = mathfn_built_in (type, BUILT_IN_SQRT);
-
-         if (sqrtfn != NULL_TREE)
-           return build_call_expr_loc (loc, sqrtfn, 1, arg0);
-       }
-
-      /* Optimize pow(x,1.0/3.0) = cbrt(x).  */
-      if (flag_unsafe_math_optimizations)
-       {
-         const REAL_VALUE_TYPE dconstroot
-           = real_value_truncate (TYPE_MODE (type), dconst_third ());
-
-         if (real_equal (&c, &dconstroot))
-           {
-             tree cbrtfn = mathfn_built_in (type, BUILT_IN_CBRT);
-             if (cbrtfn != NULL_TREE)
-               return build_call_expr_loc (loc, cbrtfn, 1, arg0);
-           }
-       }
-
-      /* Check for an integer exponent.  */
-      n = real_to_integer (&c);
-      real_from_integer (&cint, VOIDmode, n, SIGNED);
-      if (real_identical (&c, &cint))
-       {
-         /* Attempt to evaluate pow at compile-time, unless this should
-            raise an exception.  */
-         if (TREE_CODE (arg0) == REAL_CST
-             && !TREE_OVERFLOW (arg0)
-             && (n > 0
-                 || (!flag_trapping_math && !flag_errno_math)
-                 || !real_equal (&TREE_REAL_CST (arg0), &dconst0)))
-           {
-             REAL_VALUE_TYPE x;
-             bool inexact;
-
-             x = TREE_REAL_CST (arg0);
-             inexact = real_powi (&x, TYPE_MODE (type), &x, n);
-             if (flag_unsafe_math_optimizations || !inexact)
-               return build_real (type, x);
-           }
-       }
-    }
-
-  if (flag_unsafe_math_optimizations)
-    {
-      const enum built_in_function fcode = builtin_mathfn_code (arg0);
-
-      /* Optimize pow(expN(x),y) = expN(x*y).  */
-      if (BUILTIN_EXPONENT_P (fcode))
-       {
-         tree expfn = TREE_OPERAND (CALL_EXPR_FN (arg0), 0);
-         tree arg = CALL_EXPR_ARG (arg0, 0);
-         arg = fold_build2_loc (loc, MULT_EXPR, type, arg, arg1);
-         return build_call_expr_loc (loc, expfn, 1, arg);
-       }
-
-      /* Optimize pow(sqrt(x),y) = pow(x,y*0.5).  */
-      if (BUILTIN_SQRT_P (fcode))
-       {
-         tree narg0 = CALL_EXPR_ARG (arg0, 0);
-         tree narg1 = fold_build2_loc (loc, MULT_EXPR, type, arg1,
-                                   build_real (type, dconsthalf));
-         return build_call_expr_loc (loc, fndecl, 2, narg0, narg1);
-       }
-
-      /* Optimize pow(cbrt(x),y) = pow(x,y/3) iff x is nonnegative.  */
-      if (BUILTIN_CBRT_P (fcode))
-       {
-         tree arg = CALL_EXPR_ARG (arg0, 0);
-         if (tree_expr_nonnegative_p (arg))
-           {
-             tree c = build_real_truncate (type, dconst_third ());
-             tree narg1 = fold_build2_loc (loc, MULT_EXPR, type, arg1, c);
-             return build_call_expr_loc (loc, fndecl, 2, arg, narg1);
-           }
-       }
-
-      /* Optimize pow(pow(x,y),z) = pow(x,y*z) iff x is nonnegative.  */
-      if (fcode == BUILT_IN_POW
-         || fcode == BUILT_IN_POWF
-         || fcode == BUILT_IN_POWL)
-       {
-         tree arg00 = CALL_EXPR_ARG (arg0, 0);
-         if (tree_expr_nonnegative_p (arg00))
-           {
-             tree arg01 = CALL_EXPR_ARG (arg0, 1);
-             tree narg1 = fold_build2_loc (loc, MULT_EXPR, type, arg01, arg1);
-             return build_call_expr_loc (loc, fndecl, 2, arg00, narg1);
-           }
+         REAL_VALUE_TYPE x;
+         bool inexact = real_powi (&x, TYPE_MODE (type), c0, n1);
+         if (flag_unsafe_math_optimizations || !inexact)
+           return build_real (type, x);
        }
     }
 
@@ -9476,7 +9376,7 @@ fold_builtin_2 (location_t loc, tree fndecl, tree arg0, tree arg1)
       return fold_builtin_expect (loc, arg0, arg1, NULL_TREE);
 
     CASE_FLT_FN (BUILT_IN_POW):
-      return fold_builtin_pow (loc, fndecl, arg0, arg1, type);
+      return fold_const_builtin_pow (arg0, arg1, type);
 
     CASE_FLT_FN (BUILT_IN_POWI):
       return fold_builtin_powi (loc, fndecl, arg0, arg1, type);

diff --git a/gcc/match.pd b/gcc/match.pd
index 583193ac8025b441c947844c202ad5bd99bc2c5e..a2f9405c4ac55ed087fd4b4ac0654911c5570fc7 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2480,6 +2480,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 
  (for sqrts (SQRT)
       cbrts (CBRT)
+      pows (POW)
       exps (EXP EXP2 EXP10 POW10)
   /* sqrt(expN(x)) -> expN(x*0.5).  */
   (simplify
@@ -2488,7 +2489,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   /* cbrt(expN(x)) -> expN(x/3).  */
   (simplify
    (cbrts (exps @0))
-   (exps (mult @0 { build_real_truncate (type, dconst_third ()); }))))
+   (exps (mult @0 { build_real_truncate (type, dconst_third ()); })))
+  /* pow(expN(x), y) -> expN(x*y).  */
+  (simplify
+   (pows (exps @0) @1)
+   (exps (mult @0 @1))))
 
  /* tan(atan(x)) -> x.  */
  (for tans (TAN)
@@ -2524,6 +2529,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (hypot:c @0 real_zerop@1)
  (abs @0))
 
+/* pow(1,x) -> 1.  */
+(simplify
+ (POW real_onep@0 @1)
+ @0)
+
 /* Canonicalization of sequences of math builtins.  These rules represent
    IL simplifications but are not necessarily optimizations.
 
@@ -2615,7 +2625,19 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   /* cbrt(pow(x,y)) -> pow(x,y/3), iff x is nonnegative.  */
   (simplify
    (cbrts (pows tree_expr_nonnegative_p@0 @1))
-   (pows @0 (mult @1 { build_real_truncate (type, dconst_third ()); }))))
+   (pows @0 (mult @1 { build_real_truncate (type, dconst_third ()); })))
+  /* pow(sqrt(x),y) -> pow(x,y*0.5).  */
+  (simplify
+   (pows (sqrts @0) @1)
+   (pows @0 (mult @1 { build_real (type, dconsthalf); })))
+  /* pow(cbrt(x),y) -> pow(x,y/3) iff x is nonnegative.  */
+  (simplify
+   (pows (cbrts tree_expr_nonnegative_p@0) @1)
+   (pows @0 (mult @1 { build_real_truncate (type, dconst_third ()); })))
+  /* pow(pow(x,y),z) -> pow(x,y*z) iff x is nonnegative.  */
+  (simplify
+   (pows (pows tree_expr_nonnegative_p@0 @1) @2)
+   (pows @0 (mult @1 @2))))
 
  /* cabs(x+xi) -> fabs(x)*sqrt(2).  */
  (simplify
@@ -2767,6 +2789,36 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (if (real_isinf (TREE_REAL_CST_PTR (@1)))
   { build_complex_inf (type, TREE_REAL_CST_PTR (@1)->sign); }))
 
+(for pows (POW)
+     sqrts (SQRT)
+     cbrts (CBRT)
+ (simplify
+  (pows @0 REAL_CST@1)
+  (with {
+    const REAL_VALUE_TYPE *value = TREE_REAL_CST_PTR (@1);
+    REAL_VALUE_TYPE tmp;
+   }
+   (switch
+    /* pow(x,0) -> 1.  */
+    (if (real_equal (value, &dconst0))
+     { build_real (type, dconst1); })
+    /* pow(x,1) -> x.  */
+    (if (real_equal (value, &dconst1))
+     @0)
+    /* pow(x,-1) -> 1/x.  */
+    (if (real_equal (value, &dconstm1))
+     (rdiv { build_real (type, dconst1); } @0))
+    /* pow(x,0.5) -> sqrt(x).  */
+    (if (flag_unsafe_math_optimizations
+        && canonicalize_math_p ()
+        && real_equal (value, &dconsthalf))
+     (sqrts @0))
+    /* pow(x,1/3) -> cbrt(x).  */
+    (if (flag_unsafe_math_optimizations
+        && canonicalize_math_p ()
+        && (tmp = real_value_truncate (TYPE_MODE (type), dconst_third ()),
+            real_equal (value, &tmp)))
+     (cbrts @0))))))
 
 /* Narrowing of arithmetic and logical operations. 
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e1cb93ca871d946c068c88192211fc15d82ca945..e808200ad42d66b9e1c42e1cd0e223245d54bd24 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2015-10-27  Richard Sandiford  <richard.sandiford@arm.com>
+
+       * gcc.dg/torture/builtin-math-1.c: Skip at -O0.
+
 2015-10-27  Thomas Schwinge  <thomas@codesourcery.com>
 
        PR c/64765

diff --git a/gcc/testsuite/gcc.dg/torture/builtin-math-1.c b/gcc/testsuite/gcc.dg/torture/builtin-math-1.c
index d052f5347bcdc840f3fc9723b82bad9cec26f857..4ecc98d5f5c350e8727c9586bc72dcc6d580df71 100644 (file)
--- a/gcc/testsuite/gcc.dg/torture/builtin-math-1.c
+++ b/gcc/testsuite/gcc.dg/torture/builtin-math-1.c
@@ -6,6 +6,7 @@
    Written by Roger Sayle, 16th August 2002.  */
 
 /* { dg-do link } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
 
 extern double atan (double);
 extern float atanf (float);