From 605d1297b91c2c7c23ccfe669e66dda5791d1f55 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Thu, 2 Feb 2023 11:09:26 +0100 Subject: [PATCH] middle-end/108625 - wrong folding due to misinterpreted ! 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 !. 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 --git a/gcc/genmatch.cc b/gcc/genmatch.cc index e147ab9..43bd021 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 0000000..03fc288 --- /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" } } */ -- 2.7.4