re PR fortran/25620 (Missed optimization with power)
2006-11-27 Richard Guenther <rguenther@suse.de> PR middle-end/25620 * builtins.c (expand_builtin_pow): Optimize non integer valued constant exponents using sqrt or cbrt if possible. Always fall back to expanding via optabs. * gcc.target/i386/pow-1.c: New testcase. * gcc.dg/builtins-58.c: Likewise. From-SVN: r119248
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Richard Guenther
Richard Biener
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4090db01e8
commit
9fca6f972d
@ -1,3 +1,10 @@
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2006-11-27 Richard Guenther <rguenther@suse.de>
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PR middle-end/25620
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* builtins.c (expand_builtin_pow): Optimize non integer valued
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constant exponents using sqrt or cbrt if possible. Always fall back
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to expanding via optabs.
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2006-11-27 Ira Rosen <irar@il.ibm.com>
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PR tree-optimization/22372
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125
gcc/builtins.c
125
gcc/builtins.c
@ -2601,8 +2601,13 @@ expand_powi (rtx x, enum machine_mode mode, HOST_WIDE_INT n)
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static rtx
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expand_builtin_pow (tree exp, rtx target, rtx subtarget)
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{
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tree arg0, arg1, fn, narg0, narglist;
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tree arglist = TREE_OPERAND (exp, 1);
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tree arg0, arg1;
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tree type = TREE_TYPE (exp);
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REAL_VALUE_TYPE cint, c, c2;
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HOST_WIDE_INT n;
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rtx op, op2;
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enum machine_mode mode = TYPE_MODE (type);
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if (! validate_arglist (arglist, REAL_TYPE, REAL_TYPE, VOID_TYPE))
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return 0;
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@ -2610,36 +2615,108 @@ expand_builtin_pow (tree exp, rtx target, rtx subtarget)
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arg0 = TREE_VALUE (arglist);
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arg1 = TREE_VALUE (TREE_CHAIN (arglist));
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if (TREE_CODE (arg1) == REAL_CST
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&& ! TREE_CONSTANT_OVERFLOW (arg1))
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{
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REAL_VALUE_TYPE cint;
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REAL_VALUE_TYPE c;
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HOST_WIDE_INT n;
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if (TREE_CODE (arg1) != REAL_CST
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|| TREE_CONSTANT_OVERFLOW (arg1))
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return expand_builtin_mathfn_2 (exp, target, subtarget);
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c = TREE_REAL_CST (arg1);
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n = real_to_integer (&c);
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real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0);
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if (real_identical (&c, &cint))
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/* Handle constant exponents. */
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/* For integer valued exponents we can expand to an optimal multiplication
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sequence using expand_powi. */
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c = TREE_REAL_CST (arg1);
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n = real_to_integer (&c);
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real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0);
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if (real_identical (&c, &cint)
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&& ((n >= -1 && n <= 2)
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|| (flag_unsafe_math_optimizations
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&& !optimize_size
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&& powi_cost (n) <= POWI_MAX_MULTS)))
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{
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op = expand_expr (arg0, subtarget, VOIDmode, 0);
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if (n != 1)
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{
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/* If the exponent is -1, 0, 1 or 2, then expand_powi is exact.
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Otherwise, check the number of multiplications required.
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Note that pow never sets errno for an integer exponent. */
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if ((n >= -1 && n <= 2)
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|| (flag_unsafe_math_optimizations
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&& ! optimize_size
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&& powi_cost (n) <= POWI_MAX_MULTS))
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op = force_reg (mode, op);
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op = expand_powi (op, mode, n);
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}
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return op;
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}
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narg0 = builtin_save_expr (arg0);
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narglist = build_tree_list (NULL_TREE, narg0);
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/* If the exponent is not integer valued, check if it is half of an integer.
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In this case we can expand to sqrt (x) * x**(n/2). */
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fn = mathfn_built_in (type, BUILT_IN_SQRT);
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if (fn != NULL_TREE)
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{
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real_arithmetic (&c2, MULT_EXPR, &c, &dconst2);
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n = real_to_integer (&c2);
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real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0);
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if (real_identical (&c2, &cint)
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&& ((flag_unsafe_math_optimizations
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&& !optimize_size
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&& powi_cost (n/2) <= POWI_MAX_MULTS)
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|| n == 1))
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{
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tree call_expr = build_function_call_expr (fn, narglist);
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op = expand_builtin (call_expr, NULL_RTX, subtarget, mode, 0);
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if (n != 1)
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{
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enum machine_mode mode = TYPE_MODE (TREE_TYPE (exp));
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rtx op = expand_expr (arg0, subtarget, VOIDmode, 0);
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op = force_reg (mode, op);
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return expand_powi (op, mode, n);
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op2 = expand_expr (narg0, subtarget, VOIDmode, 0);
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op2 = force_reg (mode, op2);
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op2 = expand_powi (op2, mode, abs (n / 2));
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op = expand_simple_binop (mode, MULT, op, op2, NULL_RTX,
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0, OPTAB_LIB_WIDEN);
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/* If the original exponent was negative, reciprocate the
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result. */
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if (n < 0)
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op = expand_binop (mode, sdiv_optab, CONST1_RTX (mode),
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op, NULL_RTX, 0, OPTAB_LIB_WIDEN);
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}
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return op;
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}
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}
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if (! flag_unsafe_math_optimizations)
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return NULL_RTX;
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/* Try if the exponent is a third of an integer. In this case
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we can expand to x**(n/3) * cbrt(x)**(n%3). */
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fn = mathfn_built_in (type, BUILT_IN_CBRT);
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if (fn != NULL_TREE)
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{
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real_arithmetic (&c2, MULT_EXPR, &c, &dconst3);
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real_round (&c2, mode, &c2);
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n = real_to_integer (&c2);
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real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0);
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real_arithmetic (&c2, RDIV_EXPR, &cint, &dconst3);
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real_convert (&c2, mode, &c2);
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if (real_identical (&c2, &c)
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&& ((!optimize_size
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&& flag_unsafe_math_optimizations
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&& powi_cost (n/3) <= POWI_MAX_MULTS)
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|| n == 1))
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{
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tree call_expr = build_function_call_expr (fn, narglist);
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op = expand_builtin (call_expr, NULL_RTX, subtarget, mode, 0);
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if (abs (n) % 3 == 2)
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op = expand_simple_binop (mode, MULT, op, op, op,
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0, OPTAB_LIB_WIDEN);
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if (n != 1)
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{
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op2 = expand_expr (narg0, subtarget, VOIDmode, 0);
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op2 = force_reg (mode, op2);
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op2 = expand_powi (op2, mode, abs (n / 3));
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op = expand_simple_binop (mode, MULT, op, op2, NULL_RTX,
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0, OPTAB_LIB_WIDEN);
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/* If the original exponent was negative, reciprocate the
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result. */
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if (n < 0)
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op = expand_binop (mode, sdiv_optab, CONST1_RTX (mode),
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op, NULL_RTX, 0, OPTAB_LIB_WIDEN);
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}
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return op;
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}
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}
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/* Fall back to optab expansion. */
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return expand_builtin_mathfn_2 (exp, target, subtarget);
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}
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@ -1,3 +1,9 @@
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2006-11-27 Richard Guenther <rguenther@suse.de>
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PR middle-end/25620
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* gcc.target/i386/pow-1.c: New testcase.
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* gcc.dg/builtins-58.c: Likewise.
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2006-11-26 Mark Mitchell <mark@codesourcery.com>
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PR c++/29886
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33
gcc/testsuite/gcc.dg/builtins-58.c
Normal file
33
gcc/testsuite/gcc.dg/builtins-58.c
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@ -0,0 +1,33 @@
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/* { dg-do compile } */
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/* { dg-options "-O -ffast-math -std=c99" } */
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#include "builtins-config.h"
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#ifdef HAVE_C99_RUNTIME
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double test1 (double x)
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{
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return __builtin_pow (x, 1./3.);
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}
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double test2 (double x)
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{
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return __builtin_pow (x, 4./3.);
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}
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double test3a (double x)
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{
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return __builtin_pow (x, 5./3.);
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}
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double test3b (double x)
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{
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return __builtin_pow (x, -5./3.);
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}
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double test4 (double x)
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{
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return __builtin_pow (x, 7./3.);
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}
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#endif
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/* { dg-final { scan-assembler-not "pow" } } */
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24
gcc/testsuite/gcc.target/i386/pow-1.c
Normal file
24
gcc/testsuite/gcc.target/i386/pow-1.c
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/* { dg-do compile } */
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/* { dg-options "-O -ffast-math" } */
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double test1 (double x)
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{
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return __builtin_pow (x, 1./2.);
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}
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double test2 (double x)
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{
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return __builtin_pow (x, 3./2.);
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}
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double test3 (double x)
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{
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return __builtin_pow (x, 5./2.);
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}
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double test4 (double x)
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{
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return __builtin_pow (x, -5./2.);
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}
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/* { dg-final { scan-assembler-not "call" } } */
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