From: Richard Biener <rguenther@suse.de>
Date: Fri, 18 Sep 2020 07:22:57 +0000 (+0200)
Subject: tree-optimization/97089 - fix bogus unsigned division replacement
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0f6150a5d368fc30540dac31e29f1d6d40f207d3;p=gcc.git

tree-optimization/97089 - fix bogus unsigned division replacement

This fixes bogus replacing of an unsigned (-x)/y division by
-(x/y).

2020-09-18  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/97089
	* tree-ssa-sccvn.c (visit_nary_op): Do not replace unsigned
	divisions.
---

diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index 64f1e8c9160..014b7bdfd01 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -4824,8 +4824,11 @@ visit_nary_op (tree lhs, gassign *stmt)
 	    }
 	}
       break;
-    case RDIV_EXPR:
     case TRUNC_DIV_EXPR:
+      if (TYPE_UNSIGNED (type))
+	break;
+      /* Fallthru.  */
+    case RDIV_EXPR:
     case MULT_EXPR:
       /* Match up ([-]a){/,*}([-])b with v=a{/,*}b, replacing it with -v.  */
       if (! HONOR_SIGN_DEPENDENT_ROUNDING (type))