Only allow (copysign x, NEG_CONST) -> (fneg (fabs x)) simplification for constant...

On targets with native copysign instructions, (copysign x, -1) is
usually more efficient than (fneg (fabs x)).  Since r14-5284, in the
middle end we always optimize (fneg (fabs x)) to (copysign x, -1), not
vice versa.  If the target does not support native fcopysign,
expand_COPYSIGN will expand it as (fneg (fabs x)) anyway.

gcc/ChangeLog:

	PR rtl-optimization/112483
	* simplify-rtx.cc (simplify_binary_operation_1) <case COPYSIGN>:
	Call simplify_unary_operation for NEG instead of
	simplify_gen_unary.

diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 2d2e5a3c1ca67e279239e15aff0f1fb954e01f40..f3745d86aeaa6669ee23b00cb795a92baa06b0b4 100644 (file)
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -4392,7 +4392,7 @@ simplify_ashift:
          real_convert (&f1, mode, CONST_DOUBLE_REAL_VALUE (trueop1));
          rtx tmp = simplify_gen_unary (ABS, mode, op0, mode);
          if (REAL_VALUE_NEGATIVE (f1))
-           tmp = simplify_gen_unary (NEG, mode, tmp, mode);
+           tmp = simplify_unary_operation (NEG, mode, tmp, mode);
          return tmp;
        }
       if (GET_CODE (op0) == NEG || GET_CODE (op0) == ABS)