tree-optimization/94163 constrain alignment set by PRE

This avoids HWI -> unsigned truncation to end up with zero alignment
which set_ptr_info_alignment ICEs on.

2020-03-13  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/94163
	* tree-ssa-pre.c (create_expression_by_pieces): Check
	whether alignment would be zero.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index bccc2a1a68d9d72ad05951e2644f67b8416c807a..db18605fbe4ef84bb3c353e6c8ddf9367607509f 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-13  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/94163
+       * tree-ssa-pre.c (create_expression_by_pieces): Check
+       whether alignment would be zero.
+
 2019-03-13  Eric Botcazou  <ebotcazou@adacore.com>
 
        PR rtl-optimization/94119

diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index 8bd17b82368b21bb34dd73f2acb10b59d07947bc..7b171bc4e8f986ecf613280b238abffe7a5a78ec 100644 (file)
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -2810,7 +2810,8 @@ create_expression_by_pieces (basic_block block, pre_expr expr,
              unsigned HOST_WIDE_INT hmisalign
                = args.length () == 3 ? tree_to_uhwi (args[2]) : 0;
              if ((halign & (halign - 1)) == 0
-                 && (hmisalign & ~(halign - 1)) == 0)
+                 && (hmisalign & ~(halign - 1)) == 0
+                 && (unsigned int)halign != 0)
                set_ptr_info_alignment (get_ptr_info (forcedname),
                                        halign, hmisalign);
            }