From: Andrew Pinski <pinskia@gmail.com>
Date: Mon, 13 Nov 2023 20:18:34 +0000 (+0000)
Subject: Only allow (copysign x, NEG_CONST) -> (fneg (fabs x)) simplification for constant... 
X-Git-Tag: basepoints/gcc-15~4597
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9e9279fadbd1c673c875b9d20261d2de0473f63f;p=thirdparty%2Fgcc.git

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 --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 2d2e5a3c1ca6..f3745d86aeaa 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)