From: Alexandre Oliva <oliva@adacore.com>
Date: Thu, 7 Nov 2024 05:47:15 +0000 (-0300)
Subject: allow vuses in ifcombine blocks
X-Git-Tag: basepoints/gcc-16~4555
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8e6a25b01becf449d54154b7e83de5f4955cba37;p=thirdparty%2Fgcc.git

allow vuses in ifcombine blocks

Disallowing vuses in blocks for ifcombine is too strict, and it
prevents usefully moving fold_truth_andor into ifcombine.  That
tree-level folder has long ifcombined loads, absent other relevant
side effects.


for  gcc/ChangeLog

	* tree-ssa-ifcombine.c (bb_no_side_effects_p): Allow vuses,
	but not vdefs.
---

diff --git a/gcc/tree-ssa-ifcombine.cc b/gcc/tree-ssa-ifcombine.cc
index 39702929fc01..57b7e4b62f29 100644
--- a/gcc/tree-ssa-ifcombine.cc
+++ b/gcc/tree-ssa-ifcombine.cc
@@ -130,7 +130,7 @@ bb_no_side_effects_p (basic_block bb)
       enum tree_code rhs_code;
       if (gimple_has_side_effects (stmt)
 	  || gimple_could_trap_p (stmt)
-	  || gimple_vuse (stmt)
+	  || gimple_vdef (stmt)
 	  /* We need to rewrite stmts with undefined overflow to use
 	     unsigned arithmetic but cannot do so for signed division.  */
 	  || ((ass = dyn_cast <gassign *> (stmt))