[gcc r14-5542] Only allow (copysign x, NEG_CONST) -> (fneg (fabs x)) simplification for constant folding [PR112483]

[gcc r14-5542] Only allow (copysign x, NEG_CONST) -> (fneg (fabs x)) simplification for constant folding [PR112483]

[Xi Ruoyao]

https://gcc.gnu.org/g:9e9279fadbd1c673c875b9d20261d2de0473f63f

commit r14-5542-g9e9279fadbd1c673c875b9d20261d2de0473f63f
Author: Andrew Pinski <pinskia@gmail.com>
Date:   Mon Nov 13 20:18:34 2023 +0000

    Only allow (copysign x, NEG_CONST) -> (fneg (fabs x)) simplification for constant folding [PR112483]
    
    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:
---
 gcc/simplify-rtx.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 2d2e5a3c1ca..f3745d86aea 100644
--- 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)