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[1/2] tree-optimization/97089 - fix bogus unsigned division replacement

Message ID nycvar.YFH.7.76.2009181002440.15251@elmra
State New
Headers show
Series [1/2] tree-optimization/97089 - fix bogus unsigned division replacement | expand

Commit Message

Richard Biener Sept. 18, 2020, 8:02 a.m. UTC 
This fixes bogus replacing of an unsigned (-x)/y division by
-(x/y).

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

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

	PR tree-optimization/97089
	* tree-ssa-sccvn.c (visit_nary_op): Do not replace unsigned
	divisions.
---
 gcc/tree-ssa-sccvn.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
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Patch

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))