diff options
| author | jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4> | 2013-01-28 14:43:03 +0000 |
|---|---|---|
| committer | jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4> | 2013-01-28 14:43:03 +0000 |
| commit | 0190fe95747d19aff81809330c3dac92a8a0b7c7 (patch) | |
| tree | 2a2bfc3d290925073d4af913ae01b69cfbf1aa53 /gcc/tree-ssa-math-opts.c | |
| parent | d67dd34f10e3f78ad6cbcde4361bc3593570aad0 (diff) | |
| download | gcc-0190fe95747d19aff81809330c3dac92a8a0b7c7.tar.gz | |
PR tree-optimization/56125
* tree-ssa-math-opts.c (gimple_expand_builtin_pow): Don't optimize
pow(x,c) into sqrt(x) * powi(x, n/2) or
1.0 / (sqrt(x) * powi(x, abs(n/2))) if c is an integer or when
optimizing for size.
Don't optimize pow(x,c) into powi(x, n/3) * powi(cbrt(x), n%3) or
1.0 / (powi(x, abs(n)/3) * powi(cbrt(x), abs(n)%3)) if 2c is an
integer.
* gcc.dg/pr56125.c: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@195507 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/tree-ssa-math-opts.c')
| -rw-r--r-- | gcc/tree-ssa-math-opts.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c index fad3529a4d0..2140ced495b 100644 --- a/gcc/tree-ssa-math-opts.c +++ b/gcc/tree-ssa-math-opts.c @@ -1110,7 +1110,7 @@ gimple_expand_builtin_pow (gimple_stmt_iterator *gsi, location_t loc, HOST_WIDE_INT n; tree type, sqrtfn, cbrtfn, sqrt_arg0, sqrt_sqrt, result, cbrt_x, powi_cbrt_x; enum machine_mode mode; - bool hw_sqrt_exists; + bool hw_sqrt_exists, c_is_int, c2_is_int; /* If the exponent isn't a constant, there's nothing of interest to be done. */ @@ -1122,8 +1122,9 @@ gimple_expand_builtin_pow (gimple_stmt_iterator *gsi, location_t loc, c = TREE_REAL_CST (arg1); n = real_to_integer (&c); real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0); + c_is_int = real_identical (&c, &cint); - if (real_identical (&c, &cint) + if (c_is_int && ((n >= -1 && n <= 2) || (flag_unsafe_math_optimizations && optimize_insn_for_speed_p () @@ -1221,7 +1222,8 @@ gimple_expand_builtin_pow (gimple_stmt_iterator *gsi, location_t loc, return build_and_insert_call (gsi, loc, cbrtfn, sqrt_arg0); } - /* Optimize pow(x,c), where n = 2c for some nonzero integer n, into + /* Optimize pow(x,c), where n = 2c for some nonzero integer n + and c not an integer, into sqrt(x) * powi(x, n/2), n > 0; 1.0 / (sqrt(x) * powi(x, abs(n/2))), n < 0. @@ -1230,10 +1232,13 @@ gimple_expand_builtin_pow (gimple_stmt_iterator *gsi, location_t loc, real_arithmetic (&c2, MULT_EXPR, &c, &dconst2); n = real_to_integer (&c2); real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0); + c2_is_int = real_identical (&c2, &cint); if (flag_unsafe_math_optimizations && sqrtfn - && real_identical (&c2, &cint)) + && c2_is_int + && !c_is_int + && optimize_function_for_speed_p (cfun)) { tree powi_x_ndiv2 = NULL_TREE; @@ -1286,6 +1291,7 @@ gimple_expand_builtin_pow (gimple_stmt_iterator *gsi, location_t loc, && cbrtfn && (gimple_val_nonnegative_real_p (arg0) || !HONOR_NANS (mode)) && real_identical (&c2, &c) + && !c2_is_int && optimize_function_for_speed_p (cfun) && powi_cost (n / 3) <= POWI_MAX_MULTS) { |