diff mbox series

middle-end/108625 - wrong folding due to misinterpreted !

Message ID 20230202113351.B0D6E3858412@sourceware.org
State Committed
Commit 605d1297b91c2c7c23ccfe669e66dda5791d1f55
Headers
Series middle-end/108625 - wrong folding due to misinterpreted ! |

Commit Message

Richard Biener Feb. 2, 2023, 11:33 a.m. UTC 
  The following fixes a problem with ! handling in genmatch which isn't
conservative enough when intermediate simplifications push to the
sequence but the final operation appears to just pick an existing
(but in this case newly defined in the sequence) operand.  The easiest
fix is to disallow adding to the sequence when processing !.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR middle-end/108625
	* genmatch.cc (expr::gen_transform): Also disallow resimplification
	from pushing to lseq with force_leaf.
	(dt_simplify::gen_1): Likewise.

	* gcc.dg/pr108625.c: New testcase.
---
 gcc/genmatch.cc                 |  6 ++++--
 gcc/testsuite/gcc.dg/pr108625.c | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr108625.c
diff mbox series

Patch

diff --git a/gcc/genmatch.cc b/gcc/genmatch.cc
index e147ab9db7a..43bd0212d0e 100644
--- a/gcc/genmatch.cc
+++ b/gcc/genmatch.cc
@@ -2541,7 +2541,8 @@  expr::gen_transform (FILE *f, int indent, const char *dest, bool gimple,
       for (unsigned i = 0; i < ops.length (); ++i)
 	fprintf (f, ", _o%d[%u]", depth, i);
       fprintf (f, ");\n");
-      fprintf_indent (f, indent, "tem_op.resimplify (lseq, valueize);\n");
+      fprintf_indent (f, indent, "tem_op.resimplify (%s, valueize);\n",
+		      !force_leaf ? "lseq" : "NULL");
       fprintf_indent (f, indent,
 		      "_r%d = maybe_push_res_to_seq (&tem_op, %s);\n", depth,
 		      !force_leaf ? "lseq" : "NULL");
@@ -3451,7 +3452,8 @@  dt_simplify::gen_1 (FILE *f, int indent, bool gimple, operand *result)
 	  if (!is_predicate)
 	    {
 	      fprintf_indent (f, indent,
-			      "res_op->resimplify (lseq, valueize);\n");
+			      "res_op->resimplify (%s, valueize);\n",
+			      !e->force_leaf ? "lseq" : "NULL");
 	      if (e->force_leaf)
 		fprintf_indent (f, indent,
 				"if (!maybe_push_res_to_seq (res_op, NULL)) "
diff --git a/gcc/testsuite/gcc.dg/pr108625.c b/gcc/testsuite/gcc.dg/pr108625.c
new file mode 100644
index 00000000000..03fc2889c4f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr108625.c
@@ -0,0 +1,14 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-forwprop1 -fdump-tree-optimized" } */
+
+unsigned char foo(int x)
+{
+  int t = -x;
+  unsigned char t1 = t;
+  unsigned char t2 = t;
+  /* We may not rewrite this as (unsigned char)(t - x).  */
+  return t1 + t2;
+}
+
+/* { dg-final { scan-tree-dump-times "x_" 1 "forwprop1" } } */
+/* { dg-final { scan-tree-dump-times "x_" 1 "optimized" } } */