re PR tree-optimization/93054 (ICE in gimple_set_lhs, at gimple.c:1820)

2020-01-09  Richard Biener  <rguenther@suse.de>

	PR middle-end/93054
	* gimplify.c (gimplify_expr): Deal with NOP definitions.

	* gcc.dg/pr93054.c: New testcase.

From-SVN: r280039

gcc/ChangeLog

 2020-01-09  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/93054
+	* gimplify.c (gimplify_expr): Deal with NOP definitions.
+
+2020-01-09  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/93040
 	* gimple-ssa-store-merging.c (find_bswap_or_nop): Raise search limit.
 

gcc/gimplify.c

@@ -14622,6 +14622,7 @@ gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 	{
 	  /* Avoid the extra copy if possible.  */
 	  *expr_p = create_tmp_reg (TREE_TYPE (name));
+	  if (!gimple_nop_p (SSA_NAME_DEF_STMT (name)))
 	    gimple_set_lhs (SSA_NAME_DEF_STMT (name), *expr_p);
 	  release_ssa_name (name);
 	}

gcc/testsuite/ChangeLog

 2020-01-09  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/93054
+	* gcc.dg/pr93054.c: New testcase.
+
+2020-01-09  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/93040
 	* gcc.dg/optimize-bswaphi-1.c: Amend.
 	* gcc.dg/optimize-bswapsi-2.c: Likewise.

gcc/testsuite/gcc.dg/pr93054.c

+/* { dg-do compile } */
+
+__attribute__ ((returns_twice)) int
+bp (int);
+
+__attribute__ ((noreturn)) int
+cb (void)
+{
+  return bp (cb ()); /* { dg-warning "declared .noreturn." } */
+}